Auditory Device Design Inspired by Nature by Su-young Song

Cover Image Source : http://media.web.britannica.com/eb-media/21/75121-050-6CBFE9B5.jpg ÂŠ Su young Song, Brunel University, 2014 2

â&#x20AC;&#x153;Nature does nothing in vain.â&#x20AC;? - Aristotle -

Acknowledgement Looking back, the year I spent in Brunel was a very unique and splendid time. I experienced unexpectedly generous interest, hospitality and support toward my projects and dissertation and I am very pleased to have had this opportunity to sincerely thank those who inspired and encouraged me throughout the period. First of all, I would like to express my deep gratitude toward Professor Richard Bonser, my first supervisor. Without his help, this dissertation would surely have lost its direction several times. His constant and faithful guidance and support spurred me on continuously to complete the work. Thanks to his reliable and generous attitude, I was able to tackle the previously unfamiliar study fields of biomimetics and sound physics in the direction I intended. Dr. Yanmeng Xu, my second supervisor, showed me unlimited trust. I canâ&#x20AC;&#x2122;t express how grateful I am for his belief. In order not to fail to live up to his expectations, I pushed myself harder to accomplish a successful project. I also would like to thank Mr. Stephen Green for his wise advice and friendly encouragement. He has always been a great motivator to me and it enabled me to feel the great potential of my project and he also enabled me to feel pride in it. I would also like to thank all interview respondents, and Dr. Rolf Mueller and Clair Hay who contributed to my dissertation so it could considerably contribute to knowledge in the field. Furthermore, without the help of Laith Al-Sadawi and Oliver Doyle, I wouldnâ&#x20AC;&#x2122;t have been able to succeed and complete this dissertation. Moreover, I am very grateful to my dearest friends who have always been supportive of me and given so much inspiration. Last of all, my sincerest gratitude goes to my parents who are always by my side even though we live apart.

Abstract This biomimetic project applies â&#x20AC;&#x2DC;bottom-up methodsâ&#x20AC;&#x2122; with the goal of identifying the optimum auditory device design. Beginning with diverse research into forms found in nature, this project seeks inventive and innovative ideas and solutions within the auditory industry to realise them. After extensive exploration into related sensory mechanisms within nature, bat ears were finally selected as a model to reproduce in design. There are more than 1,000 bat species in the world and their habitat and prey vary depending on the species. Due to the differences required in sensory tasks, each species has evolved distinctive ears and nose shape depending on its environment and food. As a result of the research it was identified that sound is definitely influenced by shape and my concept derives from this principle. Moreover, the trend in the audio market is increasingly about realisation of high quality sound and also individualisation of sound taste and devices. The concept behind the speaker design is to allow users to adjust sound by altering the shape of the speakerâ&#x20AC;&#x2122;s enclosure. Various approaches for shape transformation were tested, such as framefabric, origami and inflatable structures. Among these, frame and fabric structure were chosen for the working prototype in order to demonstrate the feasibility of the concept. After the sound examination of the shape-changing speaker in an anechoic chamber, results showed dissimilarities in noise-analysis graphs. To consolidate the concept, four suggestions relating to materials and structure were proposed for possible improvement.

Contents 1. Project Definition 1.1. Project Question 1.2. Objectives 1.3. Research Methodology 1.4. Dissertation Timeline

2. Literature Review 2.1. Sound principle 2.1.1. Definition of Sound 2.1.2. Three Elements of Sound 2.2. Speaker 2.2.1. History of Speaker 2.2.2. Structure of Speaker 2.2.3. Types of Speaker 2.2.4. Actuation Principle of Speaker 2.3. Natural sound 2.3.1. Four Mechanisms for Producing Sounds of Nature 2.3.2. cricket 2.3.3. cicada 2.3.4. bat 2.3.5. auditory space 2.3.6. marine animals 2.3.7. others 2.4. Sound and Environment 2.5. Target Users and Speaker Market Trends

3. Primary Research 3.1. Experts Interview 3.2. Online survey

4. Concept 4.1. Concept Ideations 4.1.1. Concept 1 : Alarming device design inspired by cricket 4.1.2. Concept 2 : Alarming device design inspired by cicada 4.1.3. Concept 3 : Microphone design inspired by bat 4.1.4. Concept 4 : Speaker design inspired by bat 4.1.5. Concept 5 : Sound scanner design inspired by bat 4.2. Concept evaluation

5. Design 5.1. Correlation between Sound and Shape 5.2. Preparation for Prototype 5.2.1. Sound inspection 5.2.2. Unit and network 5.3. Prototype Ideas 5.3.1. frame and fabric 5.3.2. Origami 5.3.3. inflatable structure 5.3.4. Comparison between the three design ideas 5.4. Material ideas 5.5. Prototyping Process

6. Evaluation 6.1. Equipment and sound source 6.2. Sound Experiment Process 6.3. Result

7. Conclusion Bibliography Appendix 7

Lizard, Cuba Photograph by Lee Daubney, Your Shot 8

I admire nature. I am dazzled by the mystique of the spiral shapes of chambered shells which have been interpreted through the Fibonacci number, to the splendid and gorgeous colours of a male peacock’s feathers and the beautiful solid structure of ice. Everything from the elegant yet rapid movement of a cheetah, the communication skills of dolphins, the fluid flutter of an eagle’s wings to the lizard’s ability to regenerate its own tail, enlightens me to how infinitive nature is. Up to now, how many transformations, and cycles of trial and error has nature been through? Everything we can see around us is a model of our planet’s best design as it represents the latest fruit in the struggle for survival. Biomimetics is the study of clues in nature to make the impossible possible. Many historic cases show that nature has been the inspiration for solving specific problems, from the Velcro inspired by a seed attached to a walking dog, to the birds which inspired the Wright brothers to invent an aeroplane. Inspiration from nature can be the catalyst for the rapid enhancing of our quality of life. The whole mechanism from the small molecules that cover our bodies to the solar system and entire universe is like an optimized pattern to tackle challenges. Therefore, the solutions we seek to our problems already exist around us. This is the premise of biomimetics. Why sound among the various design fields? Frankly speaking, sound is not an area I am familiar with. I am neither a collector who loves premium audio recordings, someone obsessed with a particular music genre or a player of a musical instrument; I am just a designer with normal ears. Completing the BFA for Industrial Design and working as a furniture designer, I have spent my life far from physics, electronics or biology. In this design project, which could be the last dissertation of my life, I wanted to challenge myself to explore this uncharted area I have never experienced before. In conclusion, the dissertation subject was chosen for auditory devices related to electronics, but which have no precedent in biomimetics.

1.1. Project Question What is an optimal design concept for an auditory device inspired by the advanced mechanisms evolved in nature?

1.2. Objectives - To comprehend various mechanisms in nature to deliver certain audio-functions. - To generate biomimetic concepts and approaches which are not found in conventional devices. - To create a prototype to prove the feasibility of the concept.

1.3. Research Methodology A variety of research methodologies were utilized to ensure this project led to an innovative example of biomimetic design. To establish the foundation of knowledge and to reach a plausible concept, secondary research was initially used. Following this primary research deepened understanding and insight, to be followed lastly by qualitative review, during which the design evaluation was carried out to ascertain the validity and utility of the design. - Secondary research: books, articles, papers - Primary research: expert interviews, online surveys, - Evaluation: design analysis - Experience prototype - Sound Experiment

1.4. Dissertation Timeline As always, well-made plans increase the chances of success. The dissertation milestones were set up in accordance with the 5Ds: Discovery, Definition, Design, Development, and Delivery from the Design Council. The crucial factor is that this study aims to make an actual prototype. Therefore, time management from research to evaluation should be efficient and regimented.

research about speakers

problems and user identification

biomimetics studies

MAY

concept ideation

JUNE

JULY expert interview

basic principle about sound

primary research online survey

Discovery

Definition

From the beginning, efforts to acquire

After the extensive background research

the broad knowledge needed for this

mostly for the literature review, finding

project necessitated understanding of the

the right direction to narrow down the

principles of sound, physics of waves, and

core issue was the following main task.

the structure and actuation principles of

The primary research and comprehension

auditory devices. Since this biomimetic

of contemporary music industry trends,

design follows a bottom-up approach

and hidden needs, will be continued at

using induction, a wide variety of natural

the definition stage. Application will

research related to sound is necessary.

be determined vaguely by whether it is relevant to the mechanism, or whether the material or shape is inspired by nature.

prototype planning prototype manufacturing DISERTATION VIVA

AUGUST

SEPTEMBER

finalise dissertation

concept determination prototype test finalize concept

Design

Development

Delivery

Next concept ideations are

After one solid concept

Evaluation of the sample and

suggested as inspired by the

is confirmed, prototype

concept feasibility will be the

integration of the research

manufacturing begins, by

final step for this project.

data and exploring all the

which time detailed plans

possible concepts. The whole

for sample making should be

concept evaluation should be

advanced.

done by Viva.

Rather than flat and linear, two dynamic diamonds (leaves) for the 5D design process model were adjusted for this project, and due to limited time, effective time management was crucial and a powerful guideline throughout. 13

Smithâ&#x20AC;&#x2122;s Green-Eyed Gecko Photograph by Anke Seidlitz 14

2.1. Sound Principles 2.1.1. The Definition of Sound

Physical quantity

Loudness

How can we recognize melody? Sound exists in the air. When waves are created through the air, it becomes a medium of moving energy

Pressure (sound intensity)

and enabling the wave to reach the human

Frequency

eardrum. This energy becomes an electronic

Spectrum (tone colour)

signal interpreted by the brain as music. The range of waves that humans can hear is called audible frequency. Frequency refers to how many times a sound wave vibrates in a second

Subjective quantity Pitch

Timbre

Figure. 2.1. Correlation between physical quantity and subjectvie quantity

and the unit of frequency is Hz (Hertz.). The

Tone colour is no different from timbre.

range of a healthy manâ&#x20AC;&#x2122;s audible frequency is

Pressure and loudness, and frequency and

from 20Hz to 20,000Hz (20 KHz).

pitch are different factors but are highly

Among the different kinds of sounds there are

relevant to each other.

small sounds, loud sounds, beautiful sounds, and noisy sounds. Whether a sound is high or low is defined by frequency. High frequency produces a high-pitched sound and the low frequency produces a low-pitched sound. Regardless of frequency, the loudness of sound depends on the amplitude of the signal. Higher amplitude leads to a louder sound and smaller amplitude makes a quieter sound (Lee, 2010).

Pressure and Loudness Both features indicate how powerful sound is but considering the criteria they are clearly different factors. When sound waves occur, there are changes in air density. It modifies air pressure and the fluctuation is called sound pressure. This pressure is proportional to the intensity of sound so the Sound Pressure Level (S.P.L) of the speaker shows the strength of sound the speaker can produce. The S.P.L

2.1.2. Three Elements of Sound

is a figure measuring the output of 1W within

Sound elements can be largely categorized

represented by a decibel (dB) which is the level

into two according to objective physical

difference compared to standard sounds.

stimuli and subjective sensual stimuli (Cha,

On the other hand, loudness is a psychological

2014). The three physical sound elements are

sound phenomenon. Perceived sound volume

sound intensity, frequency, and tone colour.

as sensed by human auditory stimuli equals

The other three sound factors concentrate

loudness. The units are phon and sone and

on the sensual aspects of loudness, pitch,

they are the quantified sound levels when a

and tone timbre. The table above shows the

human hears a 1 kHz tone from the front. Phon

interrelation between physical quantity and

refers to the level of sound which is perceived

subjective quantity.

to have the same pressure as standard sound.

1m distance. The physical sound intensity is

dB 30 40 50 60 70 80 90 100 110 120 phon 30

100 110

120

sone 0.5 1 2 4 8 16 32 64 128 2 Figure. 2.2. Relationship between sound pressure level (dB), phon, and sone

Sone is a unit of linearly scaled phon dB from

points out the high and low of sound.

40 to 100. They can be acquired from an equal loudness contour which is a graph of frequency dependence in compliance with loudness. 1 Phon is 1 dB at 1 kHz and 1 sone is 40 phon (Cha, 2014).

Timbre This is also called tone colour or spectrum. It is a distinct sound quality that distinguishes sounds even when they have the same

Frequency and Pitch

loudness and pitch. It usually refers to the

As described above, frequency indicates how

differences resulting from the mixture and

many times physical waves are repeated per

time difference of sound waves. Due to the

unit. Depending on the unit, frequency can

distinctness of sound components, sensual

be classified as temporal frequency (time) or

characteristics or acoustic impressions are

spatial frequency (space). What we use in the

different. In other words, subtle differences

acoustic field is temporal frequency. Within the

in sound waves or frequency shapes allow for

audible frequency range, the lower range is 20

the distinguishing of lion sounds, bird sounds

Hz to 200 Hz, the middle range is from 200 Hz

or human sounds (Lee, 2010). The better the

to 3,000 Hz, and the higher range is 3,000 Hz to

tone colour, the better the speaker. Taking

20,000 Hz. Some experts with well trained ears

tone colour into consideration, violin and cello

can even hear up to 26,000 Hz (Lee, 2010). Pitch

sound should be clearly distinguishable when

is a sense according to frequency. Namely, it

listening through a speaker.

Figure. 2.3. Equal loudness contour

2.2. Speaker 2.2.1. History of Speaker

types of analogue were superseded by digital

The invention of audio devices allowed people

digital audio systems and the effort to achieve

to listen to good quality music at anytime,

realistic sound quality is still ongoing.

audio. This takes us to the origin of modern

anywhere. Since Thomas Edisonâ&#x20AC;&#x2122;s sound innovation in the late 19th Century there have been several developments in the history of acoustic devices. After the first invention of the phonograph, thanks to competition between Emile Berliner and Edison, the audio industry was able to prosper. At that time, a gramophone using a glass plate with wax was invented by Emile Berliner and this led to record copying. This catalysed the gramophone business and it upgraded products day by day until the Great Depression, much like the modern-day mobile phone industry. However, the direct cause of damage to the speaker business was

2.2.2. Structure of Speaker Speakers consist of three parts: the enclosure, unit, and cross-over network. The enclosure is a box that covers the unit and network. The unit is a diaphragm that enables the fluctuation of air pressure. The network functions as an interpreter and distributor of electric signals. The quality of the speaker is determined by the combination of the features of these three parts.

the advent of radio rather than the depression itself. The golden age of radio continued even after the World War 1, whereas speaker evolution slowed from 1925. Since dynamic speakers were developed by Chester Rice and Edward Kellogg, working with General Electric, the quality of speakers has accelerated rapidly. In 1948, a 30cm diameter record which can play for 23 minutes was invented by the CBS R&D center at Columbia Records. Inc. This long hour record (long play, LP) led to mass production of record players. New LPs opened the era of high-fidelity (hifi) reproduction as well and this facilitated more realistic record sounds. Practical stereo LPs were created by Decca Records of the UK in 1956 and stereophonic LP sounds made it possible to record the atmosphere of concert halls (Lee, 2010). Developing electronic technology led to the miniaturization of the speaker and methods of music playback by photoelectrons and 18

Figure. 2.4. Speaker enclosure, unit, and circuit

magnet structure

magnet

voice coil terminals

real spider suspension metal frame

dust cover

speaker cone

front surrond suspension

Figure. 2.5. Structure of speaker

Figure.2.5 illustrates the detailed parts of the

from amplification and separates them in

unit, which is divided into three parts: magnet

accordance with register. The standard that

structure, diaphragm, and support fixture.

divides the range is called the cross-over

The magnet structure consists of top plates,

frequency. The standard differs depending on

a magnet, and bottom plates. These are

the speaker manufacturer.

to convey electromagnetic energy to the diaphragm where the energy is transited into kinetic movement to make sound. The part is divided into voice coil, diaphragm (speaker

2.2.3. Types off Speaker

cone), real spider suspension, dust cover,

Regarding the types of parts, a variety of

and front surround suspension. The support

speakers can be combined. First of all, the

fixture prevents other parts popping out from

enclosure is just a box that is made of wood

the speaker due to vibration and it consists of

or steel. However, the impact the enclosure

a metal frame, gasket, and terminals (Roman,

has on the quality of speakers is enormous.

2005). The function of each part will be detailed

The enclosure can be largely divided into two

in later sections.

types, bass reflex and acoustic suspension

The crossover network is the brain of the

if structure is taken into consideration.

speaker. Most speakers have more than one

Concerning the shape and size, it can be

unit because it is hard for one unit to control

classified into three: floor standing, bookshelf,

all the register (Crane, 2014). Therefore, a

and tall-boy.

device which can distribute the sound roles

Bass reflex and acoustic suspension are

to each unit is necessary and that is the

distinguished by a duct, the hall of the speaker.

crossover network. It filters out all the signals

Speakers with a duct are bass reflex and 19

those without are acoustic suspension. The function of a duct is to push the inner air out of the enclosure to ease pressure and create

2.2.4. A ctuation Principle of Speaker

low sound. Moreover it is more accessible to

Though the structures of its parts look

loud sounds without a large output from the

complicated, the principle of how the speaker

amplifier. The acoustic suspension, on the other

works is quite simple. This is a combination of

hand, requires a large output but it produces

a magnet, a current formed by a voice coil, and a

more natural sounds (Park, 2010). Each has

cone. The electromagnetic energy is converted

different advantages and disadvantages so

to a simple back and forth movement which

they are recommended according to usersâ&#x20AC;&#x2122;

brings on changes in the air pressure and this

taste.

produces sound.

Speaker units produce sounds by moving the

The process starts from the coil, which is

diaphragm. In accordance with the sound

located in the middle of the magnetic structure.

When the current circulates along the copper

the highest range of sound, these are tweeter

coil, conflict between the positive pole of the

for upper register, midrange for middle register,

coil and the standing magnetic field creates

and woofer for low register. There is also a sub-

electromagnetic force to push the coil. When

woofer focusing exclusively on small audio

the current direction changes, the standing

ranges from 20 to 200 Hz. Similarly super-

magnetic field attracts the coil because the

tweeters manage the highest range of sound.

current is converted to the negative pole.

The two sub-woofers and super-tweeters are

Since the diaphragm is attached to the coil,

rarely used for simple music, being commonly

it moves back and forth simultaneously. This

used for movies. The size of the woofer for

movement vibrates the air in front of the

low ranges is big and for the tweeter for high

cone and the wave finally becomes acoustic

ranges it is small. It is common for a woofer to

energy which we know as sound. This

use the cone type and tweeters use the dorm

whole movement happens in a fraction of a

type (Park, 2010).

second. The alternation of current direction is very quick and the movement can repeat up to 26,000 times per second. The speed of movement differs and the interval created by time differences creates the rhythm and pitch (Crane, 2014). While the motion moves quickly, support fixtures are also crucial in enabling this whole energy conversion. The suspension and spider pull the diaphragm back when it moves forward so it can be kept in place, functioning as a spring to enable the cone to move in a

Figure. 2.5. (from right) bookshelf speaker, floorstanding speaker, and tallboy speaker

certain range while it remains sturdy. The frame is a structure that fixes the magnetic

Figure. 2.6. when standing and generated magnetic fields REPEL

structure and diaphragm. If this frame vibrates

the cross section greatly influences frequency

by means of a cone, it exercises a bad influence

properties. Besides the diaphragm, there are

on the sound quality. Therefore, the frame

other parts that impact on sound quality.

should be designed thick and heavy.

The dust cap prevents dirt coming inside the

Since the role of the diaphragm is key in

speaker and can alternate the high range sound

speaker operation, it determines 90% of the

according to its material and shape (Crane,

sound quality. The bigger the cone, the louder

2014). On the other hand, the spider suspension

the sound as there is more air to move. The

affects low-range sound when controlling the

cone material affects the sound quality and

driving power of the diaphragm.

tone colour, and the thickness and shape of

Figure. 2.7. when standing and generated magnetic fields ATTRACT

2.3. Natural sounds 2.3.1. Four Mechanisms for Producing Sounds of Nature

the insect can produce whirring or chirping

There are various methods by which nature

depending on the speed of the scrubbing file

produces sound and these can be largely

and scraper, with temperature also influencing

classified into four mechanistic categories:

output.

a drum-like membrane, file and scraper,

Inflating membranes can be seen in frogs,

inflating membrane, and hitting a substrate.

toads, and some birds. The organ that functions

These are easily found among manufactured

as a reed in a saxophone or clarinet is named

instruments as well.

differently in each animal. For example, it is

First of all, the drum-like membrane is a

called the syrinx in birds and the larynx in

mechanism which is fundamentally a drum. It

frogs. By pushing air through the membrane

uses an empty box and by hitting a membrane

from the lungs, the animal creates vibrations,

that is attached to the box, it creates vibration

while the frequency is controlled by tightening

among the air molecules. The vibration of air

and relaxing the muscles attached to the

pressure is amplified by the container. This

membrane.

mechanism is used by the cicada and the

The final method of hitting an object is used

membrane is called the tymbal.

by beavers, termites and woodpeckers. By

Like string instruments such as the violin,

slapping a body part towards a substrate, the

cello, and guitar, some insects have their own

animal produces sounds for various purposes.

files and scrapers. Crickets, grasshoppers

For instance, a beaver slaps its tail on the water

and some ants have protruding teeth on their

to alarm others. Flickers knock on hollow trees

bodies and the adjacent body part has a file-

to attract mates. Some termites hit their heads

like structure. By rubbing these two parts,

against hard objects to make an alarm sound.

sounds. This structure is called a stridulatory organ and the sound frequency can alter

Figure. 2.8. four Mechanisms for producing sounds of nature

It is hard to imagine the loudness of the sound

celebratory songs.

they make, but when done as a colony it is

The volume of music most crickets play is not

audible for several meters (Michael, 2001).

that high. Usually it goes up to 40dB from 5

Loudness has a strong association with

meters away and this is a normal sound level

size. The bigger the animal, the louder the

heard in an office (National Park Service, 2014).

sound produced. However, thanks to some

Some crickets are able to amplify the sounds

effective evolved mechanisms, some small-

they make, such as the mole cricket which

sized creatures have powerful vocal devices

digs its own burrow and sings in front of the

to overcome their limitation in size. Cicadas,

tunnel opening which resonates the sound

for example, make full use of their resonating

making it audible up to 100m away (Bennet-

structure which is a very efficient way to

clark, 1969). Considering the size of the mole

increase loudness. Crickets also utilize a

cricket, it is only around 40mm (Wildscreen

hollow membrane to amplify sound. These

Arkive, 2012), the mechanism is very effective

clever adaptations will be further explained in

to create a high amplitude. Bush crickets are

later chapters.

also known for creating a deafening sound. They can produce high volume and pitch up to 110 dB which is the same

2.3.2. Cricket

three feet away from (Gray, 2013). How

standing

a power saw can such a small

In the Disney animation Mulan, there is a scene illustrating how Mulanâ&#x20AC;&#x2122;s grandmother tests crickets for luck. In ancient China, it was believed that singing crickets in the house would bring luck to the family. Cricket sounds are utilized as relaxing music as well since it contributes to a calm atmosphere at night in countryside areas in the fresh air. However, crickets do not, of course, make chirping sounds for human pleasure. They sing for two main reasons: to attract a mate and to defend their territories against others. Since it is only male crickets that attract the opposite sex, female crickets do not sing. The calling sound can be heard up to a mile away so female crickets can locate the male from a distance. Once she approaches near enough, the male changes the courtship and sometimes males perform post-courtship

creature make

such a high volume? The answer

lies in the mechanism. Crickets use their wings as a musical instrument. They look like fragile flat vinyl sheets but if closely examined, there are hooked teeth on the Cubitus 2 vein (Cu2) and these teeth perform as files. On the contralateral forewing, the edge which is not a rigid continuation of the surface acts like a guitar plectrum. Since it is only connected at the end of the vein, it can rotate along the teeth of the contralateral wing (Bennet-clark, 1969). By rubbing those two wings, the catching and release of the opposite 23

flexible region

mirror cells

scraping is seen when the scraper gathers the teeth, and pushes the vein inwards and the middle of the harp upwards. When the scraper escapes from the teeth, the harp returns to its

media vein

harp

radius vein Cu2 vein subcosta vein

anal node plectrum

Cu1 vein

flexible region File on underside of Cu2 vein 5mm

Figure. 2.9. Drawing of the underside of the right forewing of a male Gryllus compestris.

original shape. This alternation in shape of the harp indicates that this thin layer reflects the sound wave to spread further outwards. There was an experiment which demonstrates the function of the harp area using Bailey’s actuator technique (1970). The researchers covered the harp with Evo-stik and they witnessed the volume of sound decrease significantly. From this experiment, it was confirmed that both harp wings influence the sound resonance. Without the harp area, the sound produced by the file and scraper would be erratic (Bennetclark and Winston, 2001) but also would not

teeth and the scraper generates the chirping

radiate enough to reach the female cricket.

sound. This act is called stridulation which refers to the act of “making harsh sounds” in Latin. The file is also called the stridulitrum or pars stridens. The act of engagement and relaxation is sometimes linked to a pendulum of a clock because during the ‘escapement’ stroke, each cycle of catch and release of the plectrum on the file is associated with a single cycle of the song waveform. There are also soft parts on the wing. The mirror cells and harp, shown as the hatched part in Fig.2.9, are plates that make the sound resonant. Especially the harp is a crucial area that enables amplification of the sound produced during the interaction of the wing closing. When the two forewings meet and the plectrum scratches the pars stridens, a force is created which changes the geometry of the harp area to a triangle and the convex vein becomes more convex. The cycle of the 24

Figure. 2.10. Illustration of the cricket’s mechanism of producing sound

2.3.3. Cicada The cicada is well-known for producing the

consideration of acoustic biomimetic studies, it

loudest sound among insects.

is indisputable that cicada sound mechanisms

The small insect is able to create a din up to 100dB (Hadley, 2012) which is equivalent to a lawn mower. The mechanism which enables the cicada to do this has attracted researchers’ attention. Though

are

very promising. Then, why does the cicada

produce such a sound? There are three purpose of the music, similar to crickets: to call a mate, to court females, and to sound an alarm.

I mentioned the cricket is

Much like the cricket, the

noted for its effective sound

male insect seeks a partner

production in accordance with

with a distinct mating call for

its size, this is restricted to a

each species to ensure they

few species of cricket, such as

find their own kind in densely

the bush cricket. Compared

populated areas. The sound of a

to cricket song which is often

single cicada is deafening but

used as comfort music, the

they even make a chorus when

cicada’s buzz harasses people

singing. The males aggregate

throughout the summer, and

their singing together and

its production is somewhat

fly away in the trees. This

a mystery. Various studies

explains why we can hear

have attempted to mimic the

the cicada song even through

sound mechanism of a cicada,

closed windows. Instead of

which seems to produce an

calling back, when female

extremely loud sound with low

cicadas want to reply to a male

energy input. For instance, at

cicada, she flicks her wings in

the 21st International Congress

coquetry (Hadley, 2012). Since

on Acoustics (ICA 2013), alongside

the male can both see and hear the

his colleagues, Derke Hughes, a research

snapping wings, he approaches her, softening

engineer at the Naval Undersea Warfare

his own sound. After the acoustic duet of the

Center in Newport, Rhode Island, presented

female’s wind flicking and the male’s clicking

research on underwater sonar device sensing

sound, he changes the song to the courtship

applying cicada mechanisms. Their work

call, not only producing the courtship song,

focuses on developing active sonar systems

but also the alarm sound. This is the sound a

which can emit sounds underwater to locate

cicada makes when it is caught. Even though

other vessels (Atherton, 2013). Existing sonar

the purpose of the song seems fairly simple

system devices are too large and complicated

the mechanism that enables the sound to be

for efficient systems so replicating the

so powerful has a little secret.

cicada seems inevitable for researchers. In 25

that the tymbal mechanism is designed to store the energy slowly and release it rapidly. The rubber-like resilin material captures the energy comparatively slowly and the sudden buckling of the ribs releases the energy rapidly (Hughes at el, 2008). The tymbal is a well-designed mechanism in terms of angle and the distance of force delivery. After various experiments attempting to discover the relationship between Figure. 2.11. The tymbal is located behind their wings and attached to the front part of the abdomen.

The musical instrument of the cicada is called the tymbal. As shown in figure. 2.11,

the force and distance of the tymbal, BennetClark and Daws confirmed that the membrane is engineered to maximize the amount of energy (Bennet-Clark and Daws, 1999).

the tymbal is a white exoskeleton which can be found beneath the wings and it is the key structure that produces the buckling sound.

axial push resilin pad

The tymbal consists of three parts: a tymbal plate, four ribs and a resilin pad. To put it simply, the membrane vibrates by extracting

long ribs

probe rod apodeme pit

and releasing the muscle attached to the resilin hinge

ribs of the tymbal so it buckles inwards and outwards. This cycle of pulling and releasing

tymbal plate

the muscles repeats 300-400 times per second and the sound produced from the membrane resonates and is amplified in the hollow abdomen attached to the ribbed membrane functioning like an empty drum box. The thick resilin pad at the dorsal end of the tymbal is a crucial elastic muscle that determines the resonant properties of the tymbal. The inward movement can be influenced by the stiffness

2 mm Figure. 2.9. The anatomical drawing of the tymbal of Cyclochila australasiae

of the resilin pad. The clicking sounds are maximized mostly by

Even though the process looks simple, due

the speed of the movement and the abdomen.

to the dissonance of sound and the physics

The frequency a cicada makes is almost

of force delivery, the vibration can be unique.

singular and it decays right away. One of the

Such nonlinear acoustics are a great challenge

interesting features enabling such a loud sound

and also an opportunity for many researchers

is that the sound is nonlinear, and it becomes

to replicate the true acoustic technique of the

more linear as the pulse decays. This indicates

cicada. The other difficulty they face is that

the two tymbals donâ&#x20AC;&#x2122;t vibrate in tandem with each other so the un-uniformed sound created can have millions of variations of sound phenomenon (Acoustical Society of America, 2013). Despite the challenges, transduction of sound from mechanical energy into acoustic energy is worth extensive research as the transduction stages are fairly small and also the efficiency rate of transduction is very high. According to Bennet-Clark and Daws (1999), the mean energy of buckling all the tymbal ribs is 45.1MJ and the mean energy in a pulse of the calling song is 21.8 MJ. The variations of these values are about Âą35%. Comparing the mechanical energy released by buckling (45.1MJ) and the energy per pulse of the calling song (21.8MJ), the efficiency rate of transduction energy is close to 50%. Considering the fact that energy efficiency for the Gryllotalpa australis and Teleogryllus commodus crickets is only 1.05% and 0.05% respectively (Bennet-Clark and Daws, 1999), the effectiveness of acoustic energy transduction is much higher than in other reported animals. This is why the cicada is one of the most interesting and successful examples of acoustic sensory design.

people h a v e negative

opinions

of bats because of

bats

flying

of our image menacingly

night,

their seemingly demonic faces and, of course, vampire bats actually do feed on blood. In fact, just two tablespoons of blood are enough to feed vampire bats per day, nowhere near enough to kill a large animal such as a cow (Harris, 2011). Except vampire bats, the species are actually very beneficial species for humans as they are great insect-eaters and eliminate many agricultural pests. All things considered, the most curious and thought-provoking feature of the bat is their sensory capability. It is well-known that bats use sound waves to locate their prey and see the environment. As they have poor eyesight,

2.3.4. Bat

only being active at night, and as most of their prey is small fast-moving insects, they without

have evolved sonar navigation abilities to

considering echolocation. They are the only

survive. The principal of this ability, known as

mammal that can fly. They are one of the few

echolocation, is that a bat measures the time

creatures numbering more than 1,000 species

difference between when it emits a sound and

on the planet. They usually hang upside down

when the sound returns (Harris, 2011). After

for most of their lives and are mostly active

that it measures how far the object is from

only at night. There have been lots of fictional

the bat. Like hearing your echo when you

legends attached to bats, especially with

shout somewhere which reverberates sound,

respect to the vampire legend. It is true that

such as a cave or valley, bats are able to hear

Bats are

very

interesting even

their emitted sound return as it is deflected by other objects. This indicates that the bats brain is able to measure time as precise as an advanced stopwatch and process all the necessary information about an air wave’s speed. If you know how fast sound waves move in certain areas, as soon as a sound is emitted click the stopwatch and when it comes back click again. By using the obtained time and the speed of air pressure, calculate the distance

Figure. 2.10. The principle of bat’s echolocation

from the speed-time-distance equation. That

This sensory navigation exploiting echo pitch

is how bats use sound to build an image of the

can be applied to moving objects as well. When

environment around them.

insects move towards a bat, the returning

How they emit sounds is not very different

wave will have a higher pitch. When the prey is

from humans. They use vocal chords that

going in the opposite direction, the fluctuation

vibrate the air pressure to produce air

will be lower. This is due to the Doppler Effect

fluctuation. However, they can use high-pitch

which is a physical phenomenon suggested by

sounds which are of a frequency not audible

Christian Doppler in 1892. This phenomenon

to humans. The system is like laser-navigation

explains that wavelengths of moving sound

which is used for monitoring at night or in

can be perceived differently from actual

deep water. It is astonishing how incredibly

wavelengths (physica, 2014). An example

enhanced this sensory device is and it helps

illustrating this is a moving siren. When you

bats figure out not only the distance of an

are listening to the siren of an ambulance

insect but also the size and direction in which

while standing on the street, you can sense

it moves. The subtle changes in air pressure

the sound going up while it is moving towards

reflected back, indicating size and direction,

you and on the contrary, it goes down when it

are all detected by the bat’s ears. The bigger

passes by you and fades away. Therefore, bats’

the object is, the bigger the echo that returns

ears are almost as powerful for navigation as

because it will hit more air waves. Of course if

human eyes. Instead of size and colour which

the substance is small, the air wave fluctuation

are the main source of information for human

that returns is also small. The bat also depends

eyes in interpreting distance and direction,

on which ear hears the returning sound first

bats take advantage of the various features of

and if the sound comes to the left ear first then

sound waves.

the object is obviously to the left of the bat.

How bats are able to the make instant and

There are special complex folds in bats’ ears

accurate sensory computation has long been

which aid them in pointing out the exact angle

a mystery for researchers. Many engineers

of the target (Harris, 2011). When the air hits the

have studied and experimented with the

folds at a certain position, automatically the

baffle shapes of bats’ ears and noses. Some

angle and direction are computed and drawn

bats make sounds with their mouth but others

in a bat’s brain like a surveillance radar.

emit sound through their nose. It is not fully

understood yet but the evidence seems to

various habitats and prey evolved different

suggest that the specific nose structure of

nose and ear shapes across different species

bats facilitates accurate pin-pointing of prey

due to different sensory tasks. Since there

(Harris, 2011). Noseleaves are parts of the skin

are more than 1,000 types of bat and they are

which protrude leaf-like on some bat species

dispersed all over the world from desert to

and they have attracted many scientists’

rainforest, their food naturally varies by habitat

attention, particularly their combination with

and species. Like Vampire bats, some feed

the ear folds as an influential element in

on blood, some pursue fruits and vegetables,

sonar interpretation. According to researchers

some pursue only insects, while others feed

at Mueller’s Bio-inspired Technology (BIT)

on fish, reptiles, birds, and mammals. For

Laboratory,

diffracted

example, it was suggested that the horsehoe

depending on the geometry of ear shapes,

bat, whose nose is twice as long as the nose

the frequency, and the direction of sound

of other bats, can emit a highly concentrated

movement (2011).

sonar beam. Another finding of Muellers

An interesting fact arising from research

revealed that the tragus in the big brown bat

into bats is that such versatile adaptability to

has a crucial function in the sidelobes. This

ultrasonic

can

Figure. 2.11. Clockwise from top left: Thomas’s fruit-eating bat (ARTIBEUS WATSONI), Buffy flower bat (EROPHYLLA SEZEKORNI), Cuban flower bat (PHYLLONYCTERIS POEYI), Leach’s long-tongued bat (MONOPHYLLUS REDMANI), orange nectar bat (LONCHOPHYLLA ROBUSTA), Geoffroy’s tailless bat (ANOURA GEOFFROYI)

responsible for almost half of the information about the direction of the target according to information-theoretic

analysis

(Blanchard,

2011). Virtual removal of the tragus causes the elimination of an entire set of sidelobes. This indicates that the shape is not just that way by coincidence, but it has evolved to be most suitable for sonar analysis. Intriguing experiments of Muellerâ&#x20AC;&#x2122;s employ physical models resembling bat ears to explore the varying beam patterns in compliance with different pinna shapes. The engineers collected geometries of pinna samples from 59 different bat species utilizing high resolution Fig.2.12. The digitized shape of average bat pinna

micro-computer

tomography.

The

final

digitized sample has an obliquely truncated tragus extrudes from the ear and can be found

horn (Fig.2.12) Among various bat structures,

in most mammalian ears as well. Sidelobes

three parts â&#x20AC;&#x201C; the vertical ridge, pinna rim,

are regarded as quite useless to humans as

and antitragus â&#x20AC;&#x201C; were selected according to

sonar devices. However for bats, they are

the potential sensory impact of the baffles. A

very important sonar sources which are

pan-tilt unit device was used to measure beam

Fig.2.13. Comparison of deformation and beam pattern difference between real pinna and prototype.

pattern changes

according

different baffle shapes. They discovered that even the parsimonious shape model shows that sonar diffraction occurs as the transformation of the ear proceeded (Mueller, 2012). This whole experiment and the data gathered about bats’ sonar localizing systems suggest that their mechanism is a result of understanding the full features of sound travel and the utmost utilization of such features. If the correlation between the shape and sound is identified, it will definitely lead to a significant technological leap.

engineering the

shape

the space, a variety of resonating frameworks can be realised. For instance, an anechoic chamber is the world’s quietest room and it absorbs every resonant sound. People who experience the anechoic chamber for more than a few minutes can even hear sound bouncing inside of the body (BBC, 2013). Even though it is an artificial environment, it is definitely an intriguing subject because it resembles the universe in terms of having no returning sound. Caves are a representative example of a space

2.3.5. Auditory space

that resonates sound well. Even water drops

Not only living organisms, but environmental

that caverns are dim, dark and mysterious

features

acoustic

places. From ancient times, caves were used

resonance were also investigated for this

for auditory purposes. Music and dance were

project. The sound experience humans have

important in rituals and paintings left in some

relates to fluctuation in air pressure as well

caves confirm that music was performed there.

as substances which reflect waves. Aiming

Images are sometimes clustered in certain

to enhance the general quality of auditory

areas and acoustics expert Iegor Reznikoff of

experience for humans, even though the ‘space’

the University of Paris suggests that “there

is not living, auditory space is important in

might be a relationship between the location of

biomimetic design idea.

the painting and the quality of the resonance

Some spaces qualify as more suitable acoustic

in the place (Than, 2008).” This study was not

environments while others provide unique

fully confirmed, but other experts agree that

experiences as if sound resonance did not

there seem to be sensory reasons for clustered

exist. This is because the reverberation time

images in caves.

varies depending on the characteristics of

Some caverns are still in use for acoustic

the room and the material surrounding the

purposes. Cathedral chamber in St. Michael’s

space. By adjusting different materials and

Cave, located in the British Overseas Territory

enabling

particular

can be heard clearly adding to the perception

of Gibraltar, currently serves as an auditorium.

Cathedral chambers musical properties allow

This place is utilized as a venue for various

for the blending of tones into well-organised

art purposes such as pop concerts, dramas,

sounds (Costasur, 2005). To measure what

orchestras and operas. According to experts,

determines suitable musical venues, some of

Table 1

Table 2

Table 3

Table 4

Table 5

Table 6

Table 7

Table 8

Table 9

Table 10

Table 11

Table 12

Figure. 2.14. These tables show the musical properties of each cave. Tables 1-3, Pertosa caves. Tables 4-9, Castelcivita caves. Tables 10-12, Castellana caves.

the criteria were tested to assess the quality. Innace and Trematerra, researchers in the

2.3.6. Marine animals

department of Architecture and Industrial

It is hard to imagine underwater animals also

Design at the Second University of Naples

listening to sound. Because our eardrum is

conducted comparative analysis between

not designed to vibrate sonar waves through

three

Castelcivita

water, we cannot hear sound in water. However,

caves, and Castellana caves all in southern

auditory mechanisms in marine animals are

Italy. Among the three, the Pertosa caves and

more developed than land animals. It is not

Castelcivita caves were used as sites for plays

only bats that can use sound for navigation,

and shows. T30, EDT, C80, D50, and Rasti were

so do whales and dolphins. Since light is

measured after exploding balloons in certain

scattered and weakens after only a few

area of the caves and then recordings were

hundred meters depth underwater, marine

made by GRAS 40 AR ½’’ microphones. As seen

animals’ eyesight cannot rely on it for sight. On

in the tables on the left, the reverberation times

the other hand, sound travels much faster in

in the three caves were not excessive. Though

the water than the air, so it is more challenging

Rasti values indicate they were not perfect

to understand signals from the same species

for human speech, the C80 values are in the

or from a predator because all sounds mix

intermediate range for optimum symphony

together. For this reason marine animals

or classical music concerts (-2 dB < C80 <

have more elaborate sensory mechanisms

2dB). This reveals that parts of the natural

not only for alarm calls and courtship but also

environment are ready-made for musical

for human-like communication and finding

amusement.

prey, or for finding members of their species,

caves;

Pertosa

caves,

such as a school or pod. Considering that bats have evolved ears to survive when vision is restricted, it is natural for marine animals to make

better use of sound in order to survive as

sonar waves are more effective than light

Fish also make sounds. There are three

waves in a marine environment.

types of sounds produced by fish: drumming,

How they produce sound is not much different

stridulation and hydrodynamics. Drumming

from land animals. Marine mammals like

can be compared to the tymbal of the cicada.

sea lions or seals use vocal folds to vibrate

By contracting and releasing sonic muscles

air moved from the lungs much like humans.

in a fraction of a second, the swim bladder

Some others slap parts of their bodies on the

attached to the muscle creates a drumming

surface of the water or slap body parts together

sound. In addition to the sonic medium there is

to produce distinct sounds. Cetaceans such

the ribbed membrane for cicada and muscles

as dolphins or whales use different methods

for fish, and these are similar mechanisms.

rather than vocal folds. In their nasal system

Stridulation, as it means literally, is also the

there are several air sacs and plugs that open

same method used by a cricket. By rubbing

and close so the air moves from one air sac to

or gnashing bones or teeth together, they

another. This movement causes vibration and

frighten invaders into their territory. Normally

reverberation of the fat in the melon, part of the

stridulation can produce higher pitch sounds

nasal system and which accounts for a great

than drumming. Last of all, hydrodynamics

portion of a whaleâ&#x20AC;&#x2122;s body. For instance, the

are not intentional sounds like the others

head of a sperm whale weighs more than 30%

as they are created by the rapid changes in

of the whole body and 25% of the total length

direction or velocity of the animal in the water.

(Sons demar, 2004). The hollow melon in the

However, this hydrodynamic is very important

head, covered by wax, plays an important role

as the noise created gives predators and prey

in sonar resonance and after passing through

information about animals in the vicinity

to the water, the air wave transforms into

(Discovery of Sound in the Sea, 2010).

clicking sounds. Not only clicking sounds, but there are also various forms of miscellaneous vocalization created by marine animals that are indecipherable to us including warbles,

2.3.7. Ormia ochracea

whistles, and bell-like sounds, all of which play

Ormia ochracea is a kind of fly and a

an important role in signaling.

parasitoid of crickets. Ronald Miles, professor of Mechanical Engineering at Binghamton University, says its special hearing ability facilitates a female fly to locate a male cricket by its chirping sound so it can leave the ormia ochraceaâ&#x20AC;&#x2122;s larva. The larva grows up inside the cricket eating the hostâ&#x20AC;&#x2122;s body. Neal Hall, an assistant professor of electrical and computer engineering at the University of Texas, reports that one reason for their capability is that their ear is so small (Manke, 2014). Unlike humans

Figure. 2.15.The nasal complex of the sperm whale

sensing the direction of the sound source by

difference between the ears, sounds

reach

both

as possible to natural sound. The hearing

ears at the same

mechanism of this fly can also adjust to a

time because its

directional hearing aid, yet as the microphone

head is so small.

uses a battery, loss of energy has always been

To overcome this

an issue. The new mechanism imitating the

challenge,

the

fly

unique

rigid

connection

which

acts

evolved

the microphone user to experience as close

teeter-totter mechanism is believed to solve this problem.

like a see-saw connecting ears. This amplifies small

There are numerous, and even unlimited

differences in arrival time so flies can hear

living things and natural substances that are

more clearly and detect sound direction with

intriguing enough to explore. However, six

ease.

creatures and one substance were chosen here

This finding has been applied to many

to discover the mystery of audible devices

acoustic devices. For instance, Hall published

and interaction with sound waves and other

his work on microphones imitating the

creatures. From crickets and cicadas, the

teeter-totter vmechanism in Applied Physics

efficiency of sound volume compared to size

Letters. Through this application, more energy

proves that a small size doesnâ&#x20AC;&#x2122;t necessarily

efficiency can be achieved with a simpler

correlate to weakness. Bats suggest that

method than current designs (Manke, 2014).

there is a relationship between shape and

Effective sound delivery is important for

sound and these are even able to transform

enjoyable listening but reducing background

their body shape to make full use of sound.

noise outside of the key sounds is also

Auditory space is not negligible at all because

essential. Many auditory device business

it is a factor that determines the quality of

producing speakers, earphones and headsets

sound. Marine animals are specialists and

have faced this problem and tried to enhance

have survived where sonar energy is utilized

the technology to eliminate such white noise

as powerful tool. Last of all, Ormia ochracea is

generated by the movement of electrons

an example of something that conquers the

inside the conductor. Another imitation of

obstacle of size with many unique methods.

directional hearing is seen by Miles who

What I have learned from these examples is

discovered a way to minimize adverse noise

that they are really similar to our own musical

effects in microphones. Milesâ&#x20AC;&#x2122;s microphone

instruments. Of course, their mechanisms

achieved a noise floor of 17 dB lower than

are distinct from other tools; however, during

conventional

this study, it was tempting to assume that

the two

hearing

aid

microphones floor

somehow our ancestors had also been inspired

indicating the microphone is sensitive to

by the animals around them in nature. That is

the quietest sounds. Getting rid of passive

how humans evolved throughout history â&#x20AC;&#x201C; by

damping makes the diaphragm vibrate at

learning and absorbing technologies from our

its natural frequency and this feature allows

surroundings.

specializing

minimising

noise

2.4. Sound and Environment It is generally believed that it is enough to have a good audio system in order to listen to good quality music. Some experts assert that the listening environment is also a crucial factor in determining premium sound quality. Young-dong Lee, audio critic and manager of Audio Information and Culture Lab, says depending on the location and methods of audio installation, sound can change greatly (2010). Usually the audio system is located in a living room but it can become merely a decoration due to poor installation. To listen to music effectively, reverberation time must be considered. Reverberation refers to the time that sounds remain after occurring, also known as standing wave. For instance, while walking in high heels in a quite hall, the sound made stays in the hall for a while due to the structure and materials of the building. This is because the sound energy remains within the building due to acoustic wave reflection. Places without reverberation time are not appropriate for listening to music. There are certain factors that determine the reverberation time of a space. Hard and solid materials reflect sounds well, such as concrete and rock, whereas soft and cushiony materials like curtains or carpets absorb sounds. By mixing up soundreflective material and sound-absorbing materials properly, the desired reverberation time can be reached. The structure of the room is an important factor too. Between flat parallel walls, sounds reflected from each wall can meet at the intermediate location and create sound interference. If the two waves meet in phases it can increase the frequency, which is called constructive interference. On the other hand, destructive interference is a dead spot made when the waves are out of phase and the waves die (Nave, 2009). So, box shaped venues are not recommended for enjoying sounds and that is why many halls are fan-shaped. Wall textures also influence sound waves with flat walls not spreading the waves out evenly and creating an out-of-tune echo back like when a speech is heard on wide ground. Making stair-like walls or wave-formed walls helps to prevent this phenomenon and balconies in concert halls are thus not only there for aesthetic purposes, but for sound diffusion too (Woo, 2013). It is also possible to control standing waves by allocating different furniture (Lee, 2010). The preferable

Fig.2.16. Fan type (left) and shoebox type (right)

reverberation time differs according to the music genre so it is better to understand what the most effective standing wave is for each music type.

Fig.2.17. Palau de la MĂşsica Catalana Complicated decoration of wall disperse sound and provide more naturally and abundantly.

2.5. Target Users and Speaker Market Trends Hundreds of new designs are released into the market every year. Even if an idea is innovative, it is quite rare to see it become a real product and even rarer a market leader. If people accept every new idea generated by designers, the world would be full of useless trash. The reason for market failures could be a lack of creativity, falling out of fashion, or low functionality. Some skilled designers often witness designs similar to their own original ideas, which died out long time ago, suddenly reappear and take the spotlight. This can happen because the technology the initial idea was dependent on was not fully developed at the time, or didnâ&#x20AC;&#x2122;t match the needs of the market at that time. Therefore, ingenious ideas which donâ&#x20AC;&#x2122;t meet human needs cannot qualify as successful design. With this in mind, research into the marvelous acoustic mechanisms of more than 6 living organisms and the natural environment will be useless for successful design if user need is neglected. This section will provide a basic introduction to the speaker 37

industry and current market trends to identify the potential areas for effective design. The research allowed for the refinement of potential design areas and among the many possible auditory devices – speakers, amplifiers, equalizers, recorders, CD players, microphones, earphones, and headsets – the speaker market is highlighted for its popularity and representativeness among all acoustic devices. One of the hardest areas of business to get right is in appealing to the subjective emotions and five senses of the customer. It is not easy to find the best speaker design because the standard for such varies depending on an individual’s emotional tastes. Some people have a preference for mellow and soft sounds, others value sound accuracy, whereas others might enjoy dynamic music genres such as metal rock, and the power of amplification will be important for this. Tastes also differ by country and for someone with no knowledge of audio devices, seeking recommendations for speakers online is as hard as buying stocks without any knowledge of the stock market. It is even hard to find agreement on good brands or specific types. Take the mobile phone industry, for example, and Apple and Samsung are likely to come to mind due to the power of the brand over consumers so even the market looks like an oligopoly. On the other hand, the audio market is much more diverse in order to fulfill the needs of various listeners. There could be some people claiming that the cheapest speaker is the best whereas some audiophiles look for multifunctional speakers and are never satisfied with any type of speaker. They collect different types of audio system nevertheless and this often threatens to deprive them of their savings until they find the perfect partner for audible amusement. In South Korea, there is even a joke that the three hobbies that destroy men include cars, cameras, and speakers. Not content with collecting audio devices, some even produce their own DIY speakers. Kim-cheon Lee is a Korean artist who created his own speakers from recycled paper and wood, and they even look like distinctive works of art compared to conventional speakers. The motivation behind them was simply that he didn’t have his own audio capable of a high volume in a temple where he was working. As audio is a prerequisite for his work, he started to make speakers for fun and this fun became a work of art (Goo, 2006). As the number of people fascinated by audio is increasing, the market of high 38

Fig.2.18. The artist, Kim-cheon Lee with his speaker

quality sound is getting broader. According to BillboardBiz, the need for premium audio and high-res audio is growing and it is turning into a major trend from CES 2014. Especially the premium headphone market now accounts for 40% of the $2billion U.S. headphone market, growing exponentially from 2012. Unit sales grew 61% in 2012 compared to 2011 and sales growth continued until 2013 when sales growth was 37% stronger than it had been in 2012. From November 24th to December 21st 2013, unit sales of headphones over $100 by Beats Electronics and Bose peaked, recording a 96% growth in sales (Pham, 2014). Furthermore, high resolution audio is getting more limelight from audiophiles after being unnoticed for a long time because of the popular MP3 format. High resolution has not yet been fully defined but it commonly refers to audio with higher sampling frequency than CDs. How much sample is recorded per second when the acoustic sound wave is converted into digital is called sampling frequency. CDs usually have sampling frequency of 44.1 kHz at 16-bit whereas high-res audio files is 24-bit / 96 kHz or 192 kHz. The more bits there are the closer the sound is to natural analogue sound (Phillips, 2014). There are various file formats such as ALAC, AIFF, DSD but the representative formats are WAC and FLAC. Thanks to the development of acoustic energy digitalization techniques, we can access lossless music sources for free. Many big enterprises such as Sony Corp, Universal Music Group and Warner Music Group have announced their support for the enhancement of the high-res audio. Some surveys suggest that 60% of consumers with a medium level of interest in audio say they are willing to pay for high quality audio digital. Likewise, there are various listeners and the world of acoustics is profound. From normal consumers to audiophiles, there are many areas to be considered in order to achieve a successful auditory design for sound preference diversity. The trend is toward more natural sounds without distortion and the need for premium quality is increasing. How to reconcile this with inspiration from nature is a key objective of this project.

Panther, Tampaâ&#x20AC;&#x2122;s Lowry Park Zoo Photograph by Joel Sartore 40

During the deep research into articles and papers, I was inspired in various ways for acoustic design development. However, in order to turn these vague inspirations into more feasible concepts, more specific and accurate information was needed. In this process, expert interviews and online surveys were implemented to grasp the profound information and solidify these initial inspirations.

3.1. Expert Interviews One of the most intriguing but also inaccessible areas of knowledge I was especially eager to achieve was related to bat research. It was obvious that there are abundant studies I could access through the internet but many essential questions for my research were left unanswered despite the numerous existing sources. From the list of papers and researchers from the â&#x20AC;&#x153;166th Meeting: Acoustical Society of America,â&#x20AC;? I obtained contact information for researchers involved in bat ear projects. After sending several emails to these experts, I managed to arrange an interview with Dr. Rolf Mueller, an associate professor at Virginia Tech College who is referenced in bat ear and nose studies. The interview

Fig.3.1. Dr. Rolf Mueller An associate professor at Virginia Tech College

was via Skype and was held on July 3rd while he was in China for field research. The questions total 9 and the interview took approximately 35 minutes and the edited answers are below.

1. Are there several biomimetic devices depending on your project aims to draw a specific result or just one? What types of methods do you apply? If you consider normal auditory tools which are the ears and nose, there are two types of devices that are artificial emitters and artificial receivers. Other than that we do not have anything more specific since we are working on the fundamental science. What we do is to take parts off from bats and see how those parts work.

2. In your paper, “Design of a Dynamic Sensor Inspired by Bat Ears”, you describe how the geometry of the ear was sampled. Could you describe to me in more detail how this works and explain why micro-computer tomography was better to utilize instead of biological morphometrics? The process is only used for bat specimens. When we are ready with, for instance, a big brown bat specimen, we dissect the body and have the ears and noseleaves or head itself out of the body. These parts are placed in a CT machine. This is like a medical CT but a smaller version with higher resolution though the image scale is smaller. We can get transmission and X-ray images from many different directions and angles from the machine. These collected images are combined together to create cross sections of tissue in 3D dimension. Depending on the density of the data and whether it is lower or higher than a certain density, we sort them out as air or tissue. There are certain different reasons for choosing tomography or morphometric. If you have enough time and didn’t decide what should be measured without any concentration on a specific subject, tomography is preferable. However when you have a certain aim to accomplish, morphometric methods are more often used. That is the difference. 2.1. Could you name the CT device? It is called the Skyscan 1172 from Bruker brand.

3. In your paper, I was impressed with baffle prototyping and the impact of beam pattern changes in relation to dynamic shape. Do you know any other similar experiments or studies for prototyping about different shapes of animal acoustic baffle? Yes. There is also a study about antenna design inspired by bat ears. The researcher’s name is James Flint and the title of his article is “IEEE Antennas and Wireless Propagation Letters.” The antenna uses electromagnetic waves and that is the one I am aware of in relation to acoustic baffles.

4. Bats unique noses and ears seem to be specifically adapted to their different habitats and food sources. Do you have accumulated data for the correlation between the shape of the ears or nose with prey or habitat? Or, are you able to conclude that a particular feature allows a bat to adapt to specific circumstances?

Not yet. What we are able to observe is to get the sound beams with different species in the same family tree. As you found from the paper, there are clear differences in beam patterns according to changes in ear shapes. Of course they are relevant to different sensory tasks for their prey and habitat. But we didn’t figure out yet what changes the beams and how those sound waves are connected to particular interpretations. 4.1. Are you focusing on the bat ears only or are there any other subjects you are working on? Now not only ears but we are also study flying and swimming behavior of bats and we are attempting to inspect the relationship of sonar to their behaviors.

5. According to research, there are four types of sounds produced in nature: 1. vibrating a drum-like membrane (ex. Cicada); 2. Using file and scrapers like crickets; 3. Vibrating a membrane such as frogs; and, 4. Hitting a substrate like a beaver. For bats, the nostril holes are the ones emitting sonar. How do they produce the sound? Although bats emit sounds using their nostrils, it is pretty much like human speech. Its vocal folds vibrate and regulate the air pressure when it opens and closes. So, it is same principle as the human voice but what is not specified is how they can produce such high frequencies and amplitude.

6. What is the most significant part of the bats’ sensory organs (both nose and ears)? Or, what are the main functions of each part? All the three parts of horseshoe bats’ noseleaves integrate to deliver the electric acoustic function which works like a megaphone deafer rather than each part having separate functions.

7. There are more than 1,100 bat species in the world. What type of bat is the most adaptable to various habitats and what characteristics enable them to adjust? What are their features of the nose and ears? I am not aware of the most versatile one for various environments. There is one that can live in both nature and artificial environments. But it is still difficult for them to live in cities since the different sonar set will change their boosting habits and tasks. I don’t think versatility has small things to do with other parts of the lifecycle. The 44

more interesting fact about their sonar sensing is that they can get into very dense environments. The echoes bring all the sound effects such as amplifications of tweaks and side lobes and how they can manage all the mixed dynamic sounds is amazing feature that bats have.

8. Many sound application inventions were inspired by natural echolocation systems such as submarines detecting enemies or analysing topographic maps. What else can be further applied in accordance with selective features of bat sensory evolution? One of the applications I am interested in is to minimize a sonar device. For instance, submarines have a microphone which can emit a large sound amplitude of 6-700 microphone or hydrophone reaching up to 7-9 meters and this device is huge that fills the entire cross section of the submarine. I am looking for a solution that will minimize the size of the sonar beam system. Considering the fact that sound waves move slower in the air than in the water, the application mimicking bat noses produces more effective devices which can actually become 5 times smaller than conventional ones. This will bring a huge convenience and efficiency for the sonar detection technology. The other interesting application area in regard to utilization of acoustic localization is the bio-medical area. Doctors can use sound to see parts of the inner body to find what exactly causes problems. This technology has been developing for years and it is still a very promising area.

What I initially expect to learn from this interview is how to figure out whether there are certain relationships between shapes and sounds and how batsâ&#x20AC;&#x2122; behavior of changing their ears can connect to different computations of sonar information. From this point of view, question 4 was the most important one. Most inquiries concentrate on different approaches to sensory tasks and biomimetic methodologies. New information about examples of sensory application inspired by bat ears, detailed processes of digital tomography, and other application cases were obtained from the interview. Even though the beam pattern required for individual sensory tasks was not revealed yet, I could confirm that various pieces of research regarding bat biomimetics were ongoing.

3.2. Online Survey The online research not only struggled to identify batsâ&#x20AC;&#x2122; sensory capabilities, it was also not disclosed what people actually want when they are involved in acoustic activities. Therefore, online surveys through the Facebook social network were undertaken to identify what people want from auditory devices. The survey was conducted over around 7 days from July 14th and a total of 36 people from various countries, mostly in their 20s and 30s, took part. The questions were 10 and dealt with common sound experiences.

1. How much time do you listen to music per a day?

More than 1 hour 15 / 42%

30 minutes to 1 hour 9 / 25%

Less than 10 minutes 2 / 6%

10 minutes to 30 mins 6 / 17%

Not at all 4 / 11%

More than 40% of participants said they listen to music more than 1 hour per a day. It is clearly seen that people spare a lot of time for listening to music and it is a vital part of our everyday lives because more than 70% responded that they listen more than 30 minutes.

2. When do you usually listen to music? (choose two)

Other 4 / 5% In the shower 4 / 5%

On the move 22 / 30%

Chilling out alone 16 / 22%

During work 14 / 19%

Before sleep 6 / 8% Hanging out with friends 7 / 10%

This is a multiple choice question because people can listen to music in various situations. The majority of listening time is on the move. With portable audio devices such as headsets, earphones, and mini speakers, they enjoy their music during travel. Relaxing alone and working are the following answers accounting for 22% and 19% respectively. Regarding the fact that more than half of respondents are students majoring in the design area, it is not surprising that almost one in five uses music during work. Some people also said they always have music on throughout their daily lives, so all of them are included. The other answers were driving and preparing to go out. 46

3. What is the main reason you listen to music?

To relieve boredom 14 / 39%

To change the mood or feeling 12 / 33%

To avoid noise 6 / 17%

To enjoy music itself 4 / 11%

Almost 40% of people surveyed listened to music to relieve boredom. When considered with the fact that 30% of people listen to music on the move, as per Question 2, this is arguably expected. The second highest reason to listen to music is to change the mood or feeling. The percentage of people relaxing and hanging out with friends in Question 2 aggregates to 32% and this also shows a high correlation between how and when they utilize music. Avoidance of noise and pleasure of music itself account for 17% and 11% respectively.

4. How many times have you changed auditory devices in your lifetime?

More than 5 times 11 / 31%

1-2 times 11 / 31%

None 8 / 22%

3-4 times 6 / 17%

Considering the respondentsâ&#x20AC;&#x2122; age, in their 20s and 30s, the fact that a third of them have experienced changing auditory devices more than 5 times was unexpectedly high. Also, it was unanticipated that 3-4 times was the lowest number among them. From further question 6, what can be drawn is that if someone cares about the quality of the music experience, they tend to change devices more than people articulating their insensitivity to sound (see Question 6).

5. If you answered â&#x20AC;&#x153;more than one timeâ&#x20AC;? in Question 4, why did you change the auditory device?

Malfunction 17 / 47%

Not suitable for interior 1 / 3%

Not satisfied with quality 9 / 25%

Never changed 7 / 19%

Get bored 2 / 6%

Among people who answered more than one time for Question 4, half replied that it was because of malfunction and a quarter of them changed because of discontentment with sound quality. The option “never changed” corresponds to the answer “none” in Question 4 and has a similar percentage. A minority of people chose boredom and mismatched with the interior for changing devices.

6. Do you consider yourself sensitive to tone or sound? Please grade your sensitivity from 1 (very insensitive) to 5 (very sensitive).

Average rating 3.56

The average sensitivity to sound on a scale of 1 to 5 was 3.56 which can be elucidated as slightly higher than intermediate sensitivity. 60% of respondents chose 3 and 5 stars whereas 20% chose 1 and 2 stars. These results also associate with other questions such as 4, 7, 8, and 10. The more they are keen to sound, the more likely they have more interest in acoustic devices and are more likely to have more acute and specific needs.

7. What is your favourite music genre? (multiple choice)

Pop 22 / 25%

Rock 16 / 18%

Electronic 13 / 15%

Classic 12 / 14%

Other 2 / 2%

Hip hop 12 / 14%

Jazz 11 / 13%

One in four loves to listen to pop songs and the next most popular preference is rock which accounts for 18%. The other genres such as electronics, classic, hip-hop, and jazz are from 15% to 13% so apart from pop, the other music genre preferences are distributed quite evenly. Other than those, funk, old school hip hop, and chanson were clarified as other genres.

8. Which describes your sound preference the best?

Well-balanced 11 / 31%

Dynamic 9 / 25%

Calm and relaxing 8 / 22%

Focus on vocal or specific instruments 8 / 22%

This question connects with Questions 6 and 7 as among respondents that chose 5 for sound sensitivity, 6 of 11 prefer dynamic music. These people have stronger preference for rock, hip-hop and electronics over jazz and pop, whereas others who choose the preference indicators (dynamic, calm and relaxing, and focusing on specific sounds) prefer mostly pop. Among the most sensitive to sound (5 stars), the only option not chosen was well-balanced. This is quite interesting considering well-balanced is overall the most chosen answer. Even though pop was selected the most among the three indicators, the second genre preference rate is highly related to the sound preference: well-balanced with classic, calm and relaxing with jazz, and focus on vocal or specific instruments with rock.

9. Do you have any preference for audio/headset brands? What is your favorite brand and why? If you have none, please write down N/A. Headphone brands

Both

Speaker brands

This question aimed to identify brand recognition for auditory devices. Almost twothirds of people say they do not have any preference for audio or headsets brands. Most of the other 15 respondents said more than two brands so a total 12 brands for speakers, headphones or both. Brands given with both speaker and headphone referred were Klipsch and Sony. Amongst the brands with the most votes is Sennheiser, a headphone company. The reason for their selection is design and good quality. The other headset companies such as Monster DNA, Audio Technical, House of Marley, Apple (Beats), Urbanear, and Shure got one vote each which implies that market share is fairly welldistributed. An intriguing reason for selection of House of Marley is that the brand is known for sustainable design. Among speaker brands, Bose had the highest votes and Bang & Olufsen, and Teufel follow in sequence. Good quality was most often given as the reason for speaker preference. This brand recognition distribution suggests that the market is not an oligopolistic industry, nor is it strongly influenced by branding.

10. What is the most inconvenient thing you experience when using auditory devices? EQ balancing 1 / 3% expensiveness 1 / 3%

Unbalanced sound 7 / 19%

Noise 7 / 19%

Volume 7 / 19%

Cable 4 / 11%

Design 4 / 11%

poor compativility 2 / 5% malfunction (earphone) 4 / 11%

According to responses, there are three most common problems experienced with auditory devices: unbalanced sound, white noise, and low volume (18.9% each). Other issues include cables, poor design and malfunction (10.8% each). Other than those, some stated poor incompatibility for software, inconvenience for sound equalizing and high price. Most of the problems offered relate to sound quality over other features such as design or software.

From this online survey, the first thing to conclude is that music is an integral part of peopleâ&#x20AC;&#x2122;s everyday lives. Moreover, the responses to Questions 4, 5, and 10 suggest that people care about sound quality and are willing to change devices for better quality. Thirdly, there is a profound interrelationship between individualâ&#x20AC;&#x2122;s favourite music genres and their sound preferences. This proves that people have their own tastes and they do know what they want from devices, and can distinguish the subtle differences. Last of all, compared to other markets, the audio market is relatively free from big brand control. This corresponds with peopleâ&#x20AC;&#x2122;s tastes being diverse and the fact there are almost unlimited ways to create sounds to cater to diverse tastes.

Verreauxâ&#x20AC;&#x2122;s Sifaka, Madagascar Photograph by Robyn Gianni 52

The bottom-up method is a research approach by which broad sets of data are collected and from those theories are drawn and coherent conclusions reached. In previous chapters, diverse information was collected from the principle of sound and speakers to creatures existing in nature that have outstanding hearing and sound abilities. To combine these and drive them into one consolidated concept successfully, some steps are needed.

4.1. Concepts Ideations 4.1.1. C oncept 1: Alarm device design inspired by the cricket

4.1.2. Concept 2: An alarm device design inspired by the cicada

Concepts 1 and 2 are actually the same

Concept 2, as stated before, is an alarm device

application

sound

inspired by the tymbal from the cicada. It is

effectiveness with a small size. Concepts 1

expected to be more challenging to mimic

and 2 will be the design of an alarm device

than Concept 1 since the tymbal is a complex

for self-defense or disasters. These are the

and elaborate outcome of various mechanic

simplest ideas among the 5 and were inspired

features that maximize loud sounds. Imitation

by crickets and cicadas. Concept 1 will imitate

of the cicada mechanism is still in progress

the sound production mechanism of cricket

in many other areas such as sonar radar for

wings, stridulation. It will include files and a

underwater surveillance and other classified

scraper like a guitar and also there will be small

projects. Therefore to proceed on this concept,

areas functioning like a harp on their wings to

cooperation with mechanical engineers will

resonate sound. This will be a fully mechanical

be essential as how well the mechanism of

approach revealing how efficiently such a

storing and releasing energy at high speed is

small-sized instrument can produce powerful

replicated will be the key to success.

sounds.

The reason other auditory devices such as

the

premise

speakers or headphones were not considered

microphone will be experimented with to figure

for Concepts 1 and 2 is because there is no

out the best sound quality. Transformability

spectrum to create more than one sound such

will be applied to test sound differences by

as a guitar or drum. To do so would require

different shapes. But that is not the priority for

enlarging, which would take the device

this concept as the device is for recording and

away from the original concept. Also, there

therefore sound differences will be difficult to

are numerous small speakers already in the

pinpoint. However, more analysis is needed

market due to the development of mobile and

into any problems using the microphone.

mp3 player technology.

4.1.3. Concept 3: Microphone design inspired by the ear of the bat

4.1.4. Concept 4: Speaker design inspired by the ear of the bat

Concepts 1 and 2 are relevant to size and

In contrast to Concept 3, the design for 4 is

sound, whereas Concepts 3, 4, and 5 are driven

an emitter device, a speaker. One objective of

by curiosity about the relationship between

this concept is to enable the user to adjust the

shape and sound. From the research into

sound by changing the shape of the speaker.

bats using sonar beams to ascertain shapes

Even though it does not directly duplicate the

and the location of moving food, and the

structure of the bat ear, it is inspired by the

fact their ears and noses evolved to perform

principle of the sound and shape. Some might

particular sensory tasks, it was revealed

question whether this concept can be truly

that their acoustic organ shapes change

called biomimetic, but I would argue that it is

according to sound and they are also movable

undeniable that it was inspired by bats and

to adjust to sound waves. So, Concepts 3, 4,

also displays indirect replication by utilizing

and 5 are inspired by bats, especially the ears.

the batâ&#x20AC;&#x2122;s sound computation. Thus, this can be

Since ears are receivers not transmitters,

seen as the next step after direct inspiration

Concept 3 focuses on the design of a receiver

from nature.

mechanism similar to the bat ear mechanism

Concepts 4 and 5 are personally interesting

and for that reason a microphone was chosen

ideas

for the design. In this case, various shapes of

compliance to market needs. According to

with

regard

innovation

and

market research and online surveys, people

inspection. This also relates to auditory space

have various tastes in sound and the market

because this is much like a sound inspector

for high-res audio and premium audio is also

using sound and light. By projecting light

broadening. The rapid growth of technology

which moves in accordance with sound

will also lead to consumers in term being more

waves, Concept 5 is inspired by both bats and

sophisticated about audio products. However,

acoustic space and the proposed device allows

as more and more consumers becoming

the user to visually see how waves move in

knowledgeable and particular about their own

a confined space. Technicians and sound

audio products, it will accordingly become

engineers working in concert halls or venues

more difficult to reach niche markets. There

must seriously consider the reverberation of

is no speaker whose enclosure acts like an

sound according to the architecture, wall shape

equalizer. Therefore, if this theory – there is an

and materials as they all greatly impact the

interrelationship between sound and shape- is

quality of music and experience of the listener.

proved to be right, it will be first speaker design

Moreover, everyday listeners are not aware of

that actually fulfill all the needs of adjusting

how improper installation of audio systems

sound according to customers’ tastes. This

can impact on their listening experience, so

could potential be a powerful blue ocean

this will enable them to enjoy the best quality

in the speaker market. The characteristics

of music by inspecting sound reverberation

of form changeability are also expected to

with their eyes instead of ears.

provide possibilities for aesthetic diversity

In terms of feasibility, there are abundant

which would make it more reflexive to market

examples from art of sound and light

needs, making Concept 4 very marketable and

interaction and from these there are many

appealing.

existing technologies available. For instance, the

art

installation

“Repetition

Distance” by artist Gabey Tjon shows blue

4.1.5. Concept 5: Sound scanner inspired by the bat

light movement according to sound (Hosmer, 2013). The 16 rotating blue light wires dance by the interpretation of sound waves. Also the art installation “Resonate”, exhibited at ZKM_Cube, gave viewers different sensations of resonating sounds with giant strings which when twanged like a guitar created new sounds and the light was also emitted (ZKM, 2013). Regarding these interactive installations, the proposed concept has potential to develop new products fulfilling the hidden needs of consumers. However, again this seems to be

If Concepts 3 and 4 are inspired by bat ears

quite far from the direct “imitation” of nature,

and the principle is applicable to sound and

even more so than Concept 4. There is thus a

shape, then Concept 5 is inspired by the

concern that this concept might not strictly be

bat’s computation process of sound-space

considered biomimetics.

4.2. Concept Evaluation Correspondent with market needs

Creative

Feasible

Concept 1 Concept 2 Concept 3 Concept 4 Concept 5 Imitative (more imitative :5, less imitative : 1)

Four indicators are used to evaluate the 5 concepts: creativity, feasibility, imitation of nature and correspondence with market needs. Creativity factors indicate how innovative the idea is and because there are no perfect biomimetic acoustic devices currently in use, all of them register over 2. Feasibility is taken into consideration due to the limited timescale after the viva (July 17) and restricted access to cuttingedge technology. Furthermore, for Concepts 4 and 5, it was not fully proven that the principle really works in real products so many experiments and prototyping would be necessary. This is why they get the highest rank. The imitation index is to illustrate how closely the idea imitates nature. It doesnâ&#x20AC;&#x2122;t necessarily imply that the highest is the best but it also indicates how directly the concept was inspired by nature. Some of the concepts require more thorough market research before making definitive statements regarding correspondence with market needs, so they have few marks in that area. 57

Aim To adjust the Concept 1

mechanism of the cricket to the device

Challenges 1. How can sound be amplified? 2. How can more diverse sounds be created?. 3. What is the exact user need behind the application? 1. H ow can the energy-storing and release

To adjust the Concept 2

mechanism of the cicada be recreated?

mechanism of the

2. How can more diverse sounds be created?.

cicada to the device

3. What is the exact user need behind the application? 1. What is the best quality for sound

To create a microphone which Concept 3

can sense and convert sound at the highest quality

To manufacture a Concept 4

speaker that acts as an equalizer by changing its shape

To scan empty space Concept 5

in order to ascertain the acoustic suitability of a room.

2. How similarly can the shape of bat ears be mimicked and how will this affect performance? 3. What is the exact user need behind the application? 1. How will this be visually delivered? 2. Can I get access to the necessary technical tools? 3. How can changes in sound quality by speaker shape be measured? 1. H ow can technology be used to represent sound waves by light beams? 2. How can light be made to be projected at the same speed as sound? 3. Where can the prototype scanner be made?

Fig.4.1. Aim and challenges for each concept

Creativity and imitation indicators seem to go in the opposite direction, as is the case with feasibility. On the other hand, correspondence with market needs is in tandem with creativity. Considering the timescale and success rate of the project, Concepts 1 and 2 seem safer and more appropriate. Concept 3 is quite moderate as it has the most average grades among the 5 ideas. Concepts 4 and 5 are the most challenging ideas but are also very intriguing concepts due to the possibility of exciting design. As a designer myself, chasing the most creative and best idea despite a lack of time and resources 58

is appealing. Therefore Concept 4, the speaker design inspired by the bat was finally selected to proceed on to the next stage. Both Concepts 4 and 5 are interesting and innovative, but Concept 5 is a bit off the track for this project. It neither really imitates nature nor does the device directly interact with only our vocal or hearing senses. The main reason for the selection is not only for the great potential, but also as it addresses all the project objectives. More detailed research had not yet been carried out to improve speaker design feasibility before deciding on Concept 4. The prototype planning and confirmation for expertsâ&#x20AC;&#x2122; support in sound test should be delivered after the viva as well. After that information was collected, speaker design was finally able to progress.

Peacock, Florida Photograph by Lorenzo Cassina, Your Shot 60

5.1. Correlations between sound and shape It is true that there is no existing work which thoroughly examines the interrelationship between sound waves with different shapes or materials. However, there are some studies in progress which seek to clarify the relationship between properties of boxes and sound variation. The Sounding Object Project (The SOb Project), which is part of the Disappearing Computer initiatives Future and Emerging Technologies (FET) of Information Society Technology (IST), aims to Figure out the physical properties of sound. According to their book, they implement some interesting experiments to discover how well and differently individuals can perceive the shape of enclosed spaces by sound. It was demonstrated that there are clear differences in pitch depending on the enclosure shape and Figure 5.1 shows the result of frequencies measured in a sphere with a diameter of 36 cm and a cube with the same volume which shows these explicit differences. What can we say about those listening? Are they also able to perceive the shape of a box by sound alone? The experiment proceeded with a sensory set consisting of 10 sound variations using snare drum patterns. 19 volunteers had to listen to the stimuli set 10 times each so they listened to almost 100 songs. The participants were asked whether each song came from a spherical or a cubic enclosure. The diameter of the spheres ranged between 100cm, 90cm, 70cm, 50cm and 30cm. The subjects were encouraged to have a

Fig.5.1. Low-frequency spectra of the responses of a ball (diameter = 36 cm, solid line) and a box (dashed line) at the same volume.

training phase as many times as they wanted and this was necessary for more precise results as humans tend to rely on other senses, especially sight more than hearing. The results showed that accuracy in distinguishing shapes by sound was more than 60% among average listeners only when the diameter was larger than 50cm. The answer distribution graph is shown in Figure 5.2. As it shows, the bigger the sphere and cube, the more likely the subject will answer accurately. Spheres were more constantly classified than cubes, although this sensory perception can vary depending on the listener. Sound experts can analyse the pitch and frequency range when they listen so it is obvious that they tend to be more sensitive in the series of experiments. Three conclusions arise from the experiment, firstly that the bigger the enclosure is, the easier listeners perceive differences. Secondly, the bigger the volume, like the size of the box, the clearer the distinction between sounds. Lastly, when subjects were asked about the qualitative features of sound, they often said that sounds from spheres are brighter than from cubes. Sounds are often described as ‘bright’ when they are high-frequency. On the other hand, ‘warm sound’ is more often low frequency. They conducted another 62

analysis of spectral patterns in relation to sound characteristics and

shape

perception.

While

measuring the brightness of the impulse response, they figured out the frequency at the centroid of wooden cubes and spheres is 5570 Hz and 5760 Hz respectively. This might be because spheres have smaller areas than cubes. Therefore, differences in sound are produced as it moves through Figure. 5.2. Results of the shape classification

cavities and people can sense these.

The SOb project also exploited correlograms by calculating the impulse responses. The correlograms of sound are depicted with time, frequency and periodicity. Figure 5.3 displays the correlograms for cubes with an edge of 0.5m and sphere. From this, it can be identified that cubes have one more vertical dash line than the sphere, which indicates the peak. So, in theory sound experts can hear one more pitch of sound from a cubic cavity (Rocchesso, 2003). Their methods of using correlograms to verify the sound is what I needed to inspect the feasibility of for my speaker design. How it was inspired and delivered will be explained in further chapters.

Figure. 5.3. Correlograms for the cube (edge 0.5m) and for the sphere at the same volume.

5.2. Preparation for the prototype 5.2.1. Sound inspection

like size or qualification. 3 speakers which

One of the tasks to be done before embarking

and 1 speaker that was reasonably priced

on the design visualization and prototype

for the experiment were not suitable due to

was to confirm where the technical sound

malfunctions, the huge size of the network,

support could be found to test the speaker. If

poor quality sound or lack of adaptor. The final

I couldnâ&#x20AC;&#x2122;t demonstrate the feasibility of this

choice for the unit and network parts was the

concept, the project would not be completed

2.0 multimedia speaker E-01A and E-02A from

properly. I held a simple interview with Clair

Cenos Technology. This speaker is powered

Hay, a sound engineer at AJM Productions.

via USB connection from a computer so the

I asked her two basic questions about sound

network is extremely small. That is why the

adjustment methods in the industry and

cone and network were chosen.

accessed

mechanical

sound

were given to the researcher by chance

inspection

devices. According to Clair, sound tone is

Speaker specification:

adjusted by EQ (graphic equalisers) by adding/

Powered via USB

removing certain bands of frequencies. This is

Pure and clear quality sound

all done at the mastering stage of production,

Compact and lightweight design

either electronically or using an analogue

Ultra sleek cube design

mixing desk. There are pieces of electronic

Built in active amplifier

equipment that can create reverberation to be

Extreme bass and clear treble

recorded onto music. For classical music, the

Includes 3.5mm stereo plug and USB cables

venues are usually selected because of their

Approximate size: 68(L)x68(H)x72(W)mm

acoustics, so only a very small amount of EQ

Speaker power: 3W each

or reverberation will need to be added. For the second question, I was advised to get in touch with the physics, acoustics and engineering departments of my university to access equipment. Since Brunel University has a BA in Sonic Arts program, it was not difficult to request access to those devices and receive technical advice.

5.2.2. Unit and network It is wiser to reuse the unit and network from conventional speakers as the objectives of this project donâ&#x20AC;&#x2122;t require sound experiments through electronic trials. A total of 5 speakers were disassembled to check the specifications 64

Figure. 5.4. USB Portable laptop speakers

5.2. Preparation for the prototype Many ideas for visualization were reviewed for the sake of improved design. It is basically a transformable enclosure design combined with a unit and network from another speaker so â&#x20AC;&#x153;enabling shapingâ&#x20AC;? was the key issue for the project. Among various possibilities, three design concepts were selected: frame and fabric, origami, and inflatable structure. These will be introduced below with design examples and images.

5.3.1. frame and fabric The first method that I came up with for

renowned for his spherical creations which

altering the shape was an umbrella. With a few

have an isokinetic structure and are able to

thin metal frames and a sheet of fabric, the

expand and contract by scissor-like joints. His

structure is flexible enough for extreme size

various approaches to apply transformable

alternation. There are abundant examples for

design provide many tips on how to deliver

applying this frame and fabric which are often

the speaker design in real working model.

seen in architecture, especially mobile and

Another groundbreaking approach is seen

prefabricated buildings such as tents.

in the application of minimal structures and

One enlightening and inspiring example is

skin found in the BMW concept car, GINA. By

Chuck Hobermanâ&#x20AC;&#x2122;s temporary and permanent

maximizing the elasticity of spandex fabric,

installation. He is an architectural engineer

it succeeded in bringing innovative aesthetic

and founder of Hoberman Associates. Inc and

beauty to conventional concepts of the car and manufacturing processes.

Figure. 5.5. The transformable design works by Chuck Hoberman (above) BMW Concept Car, GINA (below)

Figure. 5.6. Inspiration images

Moreover, from a biomimetic point of view,

from their wings.

the frame structure is similar to human joints

and bat wings. Like cartilage and ligaments

(NURBS) in the CAD programs, the initial idea

in our bones, sticks can allow different

started from several rotating joints adhering

maneuverability

joint

to the skin. In theory, if the frame rotates

properties. Bat wings resemble human arms

and moves around, the fabric should follow

except for the membrane skin called patagium

the movement due to the attachment to the

which extends between hand and body (Harris,

joints. This will facilitate swiftness in shape

2011). They are very flexible in comparison

adaptation from a box to a tube. There are

with bird wings which mostly move by

several issues to check for the mechanism.

muscle. Bat wings have more than two dozen

Firstly, the first row and last row should be

joints which are capable of separate degrees

at the same height or at the same grade. As

of control (Swartz et al, 2007). Thanks to the

first the raw will be attached and fixed to the

unique structure they can swim through air by

plate holding the cone; however, if the last raw

deforming their wings adaptively. If this idea

doesnâ&#x20AC;&#x2122;t fix to the same raw a supporting pillar

of frame and fabric is used, this biomimetic

will be required inside the structure to prevent

study does not only end up with sensory

all the frames spreading out without constraint

inspiration, but also body frame inspiration

and this inhibits regular form. Even if a pipe

depending

the

Non-Uniform

Rational

B-spline

Figure. 5.7. Rough sketches

is used to hold the last dots of the structure, the mechanism that enables them to go up and down will be complicated and it is not certain that the spandex fabric will expand so randomly. That is why the last raw should be fixed by one frame. The Second issue is where to install the circuit. It is useless dangling the circuit even if the shape is atypical. Lastly, the rotation’s degree of restraint should be resolved; it could be a ball hinge, a simple rotating hinge, in multiple steps or unlimited. Because it is also influenced by the elasticity of the fabric, the details were confirmed during

5.3.2. Origami Thanks to its uniqueness and aesthetics, origami is widely utilized in various products and applications. Depending on how and where the paper is folded, it can produce unlimited shapes and forms. In terms of design, fashion in particularly fully utilizes origami patterns to express various feelings such as cubic effects or clear textures as seen in the work of Issey Miyake, a Japanese fashion designer well-known for his origami-inspired fashion. Not only fashion, but daily items including furniture, lamps, shelter design and even science, have been influenced by this paper-folding art. In addition, there are many master craftsmen including Yoshi, a paper artist from Venezuela, and Paul Jackson, who wrote ‘Folding Techniques for Designers from Sheet to Form’ and other books on origami and folding which provide useful models for artists. The books provide excellent guidelines for folding skills and provided me with lots of inspiration.

Figure. 5.8. Origami technique applied in fashion (Issey Miyake, above) Paul Jackson’s book ‘ Folding Techniques for Designers from sheet to Form’ (below)

Figure. 5.9. Inspiration images

Figure. 5.9. Waterbomb structure and shape variables

There are two possible approaches to origami

triangle pieces by Studio Elisa Strozyk. The

techniques. The first is simple folding with

blanket is the combination of wooden sheets

thick paper. After learning several patterns

and fabric which thus provides both rigid and

from the origami manuals, you can then

flexible parts, and by mixing these opposites,

create new designs mixing different patterns.

unexpected shapes are built. Figure 5.11 is the

Since many foldable structures are simple

sample prototype with fabric and wooden tiles.

repetitions of the water bomb base, once the

Without any support material, it can morph

base is mastered, producing a whole structure

specifically in the pattern made by the wooden

is only a matter of time. The other strategy is

sheets. If this idea is used, identifying right

inspired by the technique applied in wooden

pattern design will be the most vital challenge.

textiles, a blanket covered with small wooden

Figure. 5.10. Wooden textile by Studio Elisa Strozyk

5.3.3. Inflatable Structure One of the most frequently used methods for shape alternation is injecting air. From swimming tubes to architecture, using this technique can achieve very dramatic changes in shape. However due to inaccessibility to manufacturing and rubber materials, as well as the limited shape transformation, it was determined that this idea should be discarded.

Figure. 5.11. Sample origami prototype Fabric + wood sheets combination

Figure. 5.12. Inspiration images

5.3.4. C omparison among the three design ideas Strengths

Weaknesses 1. L imited access to metal workshop and

Frame and fabric

Gives most

materials (hinges)

variations in

2. Flexibility of fabric

transformation

3. Aesthetic concerns 4. Sound dampening material - fabric

Origami

Easy to make and assured aesthetics

1. Structure lacks solidity (too improvised) 2. One-directional changes (size) 3. Common origami design 1. L ack of know-how in making customized

Inflatable structure

tubes 2. Restrictions in possible shapes for inflatable structures Fig.5.13. Strenghts and weakness for each ideas

Among the three ideas, the final inflatable

expanding and contracting, it is restricted in

mechanism was abandoned because of the

allowing many enclosure variations. Even

restrictions. The other two are both very strong

though it is possible to control only part of it,

and interesting designs. However, despite the

due to the insecure rigidity it would require

strong advantage that origami could bring to

too many trials to reach the most appropriate.

the design, the frame and fabric mechanism

Therefore, the first idea, frame and fabric, was

was selected for the freedom it gives in diverse

finally chosen to make a speaker prototype.

shape alternation. Because origami is only for

5.4. Material Ideas It is no exaggeration that Colour, Material, and Finishing (CMF) determine the quality of design. Especially from the concept of â&#x20AC;&#x2DC;frame and fabricâ&#x20AC;&#x2122;, the appropriateness of the material chosen and also how well it is applied are measures of the success of the project. The frame material should be stiff and strong enough to hold the structure and the fabric should be elastic and flexible but also have rigidness since soft fabric tends to absorb sound too readily. Many materials were discussed to facilitate the required elasticity and rigidity and, for instance, an air muscle was discussed as a potential material that stretches out and contracts easily. This is a pneumatic device which resembles a biological muscle and it is used in various areas such as robotics, biorobotics, biomechanics, and industry. However, it was not suitable for diverse alternation needed for this speaker. The other alternative was the robotic octopus, an artificial rubber composite. It was found through a biomimetic study into skin artefacts for the robotic octopus, which is a knitted structure of silicon rubber with nylon fabric. This knitted fabric of two different materials possesses both optimized stiffness and extensibility. If sound reflection is taken into account, however, soft materials like fabric are not really a wise choice for a speaker, as, such as in Figure 5.11, it is better to have an element of partial stiffness. Polymer-polymer composite is another option that is both rigid and soft and by heating and solid-state drawing, layers can be created with different properties allowing both: elasticity and stiffness (Alcock et al, 2010). The crucial factor to consider was accessibility and materials like rubber artefacts and polymer-polymer composite are unfortunately not very usable. One of the strong features of knitted fabric like stockings is elasticity and for my design it is the essential factor to facilitate shape transformation. However, the more powerfully it returns to its original shape, the more difficult it is to fix the shape after alternation. Therefore, it is not only about the fabric materials but also the frame and structure should have enough strength to hold form. Nevertheless, for the sake of time management and restricted access to materials, the prototype focused on how well the speaker could transform in order to examine the correlation between shape and sound. The frame material was made from 3D printed plastic and Lycra spandex was chosen for the fabric.

Fig.5.14. Air muscle (left) and Lycra spandex (right)

5.5. Prototype Process 1

pipe_octahedron. prt frame_small.prt frame_big.prt

pipe_octahedron_small.prt

1. Make a set of sample frames to confirm the

2. Create a CAD for the frame structure. Parts

details for the rotating hinge.

are Frame_big.prt, Frame_small.prt, Pipe_

After changing the material from metal to

octahedron,prt, Pipe_octahedron_small.prt.

plastic, some alternations were made. Two

In order to break the uniformity of the shape,

types of frame were produced from the 3D

the bottom pipe frame is one-fourth the size

printer at first and after that the first type was

of the top pipe frame. When all the frames are

finally selected because it had more stiffness

extended fully, it becomes a conical shape.

and stability.

Laser cut the plastic cover for the top and

Take apart the unit and circuit from the

bottom of the speaker as well as other parts

conventional speaker.

for the circuit

From the Cenos Technology speaker selected,

A 2mm-thick plastic sheet was laser cut for the

the parts were detached for use in the

covers of the speaker. The hole in the middle

enclosure. The wire connection was very

of the top cover locates the speaker cone. The

unstable so it needed extra care.

reason for it resembling a toothed wheel is to avoid overlapping the frames. The other parts are three small squares for an open box. 74

3. Check the constraints among frames and

4. Combine all the four frames in order and

convert the files into STL. File for 3D print.

complete the frame set with two pipes.

The difference between frame_big.prt and

After trying varied combinations of big frames

frame_small part is the part of the extrusion

and small frames, the order of the frames were

at the end of the frame. More extrusion allows

decided thus: big frame, small frame, big frame,

for bigger angles for rotatation. Depending on

and small frame from the top. The frames are

the limitation of the joint rotation angle and

connected by 2mm diameter rubber tubing

the location of these frames, various shape

through the halls at the end. To prevent them

formations are possible.

sticking out of the frames they were slightly fixed with super glue at the end.

Make an open box to put the circuit in it and

Make the pattern of the fabric cover.

paste the box under the top cover.

Although it is spandex material, the fabric was

The box is located near the centre while not

not springy enough as it had to be big enough

covering the hole. This is because it might

for the frames to be horizontally extended

interrupt the movement of the frame if it is too

to its limit. Two pieces of fabric were drawn

close to the edge.

for the conical shape and to prevent sound dampening, folded paper was placed over on the inside of fabric.

Sew up the fabric to make clothes for the

Fix the cone to top cover and put the circuit

frame and fasten them to the structure.

inside of box.

Through a hole in the middle of the frames and

It was important to fix the circuit inside the box

another made by connecting the two frames,

since the wire connections were very fragile.

the fabric is fixed firmly to the structure.

Fig.5.15. Completed prototype model

Attach two covers to the frame structure. Blocking the two holes in the fabric-frame structure is the final step. It was sewn through the fabric as superglue was not efficient for the spandex.

Although the prototyping process for the fabric and frame looks fairly simple, it underwent a great deal of trial and error. The plastic material chosen for the frame was not stiff enough to hold the fabric so some of it was broken during the construction process. After more than 5 pattern trials, the final pattern facilitated a wide range of rotation. The fabric did not stretch as much as expected so it became hard to anticipate the natural beauty of the curve attained by extreme stretching of the fabric. The circuit of the speaker was very unstable so the wires detached several times. With help of technicians from the electronics lab in Brunel University, soldering of the circuit board was conducted. Despite the many obstacles, the main objective of the design was achieved, which was to enable diverse shape variations. The speaker can make more than six alternations unlike the other patterns which enable only two or three. The next step, therefore, is to demonstrate the feasibility of the concept.

Alligator, Okefenokee Swamp Photograph by Melissa Farlow 78

6.1. Equipment and sound source In order to verify the practicality of the concept, an appropriate sound test was required. Fortunately, I could get considerable and helpful advice about the testing environment, devices and sound sources from Oliver Doyle, a technical operations assistant in the School of Arts at Brunel University. Since sound waves always interact with their environment, place selection is crucial. If accurate measurement of sound in relation to shape alternation is taken into account, an anechoic chamber is the optimum room for the test. Such a chamber is located in the Mechanical Engineering Department in Tower C of the university. With the help of Laith Al-Sawadi, a PhD student from the School of Engineering Design, I could use the Pre-polarized microphone installed in the chamber and noise analysis program to produce graphs of each speakerâ&#x20AC;&#x2122;s correlation between frequency and sound intensity. For the sound analysis software, Spear, sinusoidal partial editing analysis and resynthesis program and iZotope RX4, audio repair and enhancement programs were discussed first for the sound analysis program. However, both programs illustrate frequency and sound intensity fluctuations according to time sequence so differences in the graphs produced by these programs are unclear. On the other hand, LabView program and Matlab code program installed in the anechoic chamber simply describes the relationship between frequency and decibels, although it is visually more convenient to make comparisons between the different shapes.

Fig.6.1. LabView program (left) and Metlab code program (right)

For sound sources, pink noise was recommended because normal music does not include the whole frequency range; however, it was not very desirable for testing. To explain what pink noise is, it is better to define white noise first. White noise is sound that has the same intensity at every frequency. It has an impact of suppression for all other noises. Human ears are more sensitive to low frequencies such as 2-5kHz, so white noise can be annoying. Pink noise is a modified version of white noise in consideration of the nature of human ears. Pink noise has a slightly stronger intensity at a low frequency and a weaker intensity at a high frequency. People regard noise as very annoying and unmusical, yet some noise like white or pink noise can beneficial 80

as it kills other noise and stabilizes the human body and mind. The noises are similar to the sound that a fetus hears in the mother’s womb. Everyday sounds similar to white or pink noise are waves, rain, and waterfalls. Also, music such as ‘Summer 78’, OST of ‘Goodbye Lenin’ was chosen to see whether it there were any differences from the pink noise. Fig.6.2. Pink noise

6.1. Equipment and sound source Beforehand the necessary items for the test were a conventional speaker, prototype speaker, microphone, noise analysis program, and sound sources (pink noise and general music). Some of the rules were made to make the process swifter and more accurate. First of all, there were to be no changes in volume. Second, the location and direction of each cone had to be the same. Third, the conventional speaker and prototype speaker parts were the same in order to examine the differences between them (only the enclosures differed). Fourth, shape alternations had to be in order as there could not be any confusion with shapes. Fifth, each prototype speaker shape was named by case: 1, 2, 3, 4, and 5. Sixth, since the computers connected to the microphone were outside the anechoic chamber, I knocked a metal instrument in the chamber to signal to Laith, the operator, who then recorded the test. Except for the metal, there were no other acoustic options to send a signal to him. Lastly, the recording had to start 10 seconds after the music had actually started to prevent any additional delay. Because I had to hold the speaker to record its exact location, the time interval allowed me to get ready to send a signal. The sound experiment process is described below.

1. Place the speaker where the cone is centered, at the same vertical as the microphone and also 70cm away from it. 2. Connect the conventional speaker first and turn on the pink noise.

3. After 10 seconds, knock the metal instrument to tell Laith to start the recording. 4. Create the analysis for 60 seconds and switch speakers to the prototype. 5. Make the comparison graphs for both. 6. Do the same from 2 to 4 for 10 second recordings and confirm the differences between 60 seconds and 10 seconds. 7. After the experiments, it was decided to do the 10-second analysis since there were no dissimilarities between 10 seconds and 60 seconds. 8. Changed the prototype shape from 1-5 in order and recorded the sound through the pre-polarized Microphone. 9. After completing the analysis for each form, comparison graphs were drawn up for six cases (including the conventional speaker.) 10. The sound source was changed from pink noise to general music and the process was repeated from 3 to 7. The 10-second experiments were also used because there were no noticeable differences between the two tests. 11. All the information was collated and analytic graphs were drawn.

case 1 : cone

case 3 : long diamond

case 2 : hat

case 4 : two diamonds Fig.6.3. Shape variation from 1 to 5

case 5 : vase

Fig.6.4. In anechoic chamber

case 1 : cone

case 3 : long diamond

case 2 : hat

case 4 : two diamonds

case 5 : vase

Fig.6.5. Shape variation from 1 to 5

6.3. Result All the results of mutual relations between frequency and sound intensity are illustrated in Figure 6.6. When all the cases were overlapped in one graph, it was identified that it is hard to distinguish each case except the conventional speaker. It might be due to the graph containing too broad a range of information or it could be because there was very little distinctiveness between cases. Taking a closer look at the graph 2, the differences between the two speakers are very clear. At least it demonstrates that different enclosures can have a huge impact on sound since there are no changes other than that. The biggest gap between those two is almost over 15dB. Especially in the section from 260Hz to 750Hz, and 4,200Hz to 6,200Hz, the original speaker records higher noise than case 1, whereas in midrange from 750Hz to 4,200Hz case 1 has a higher noise than the other.

Figure 6.6. Comparison graphs using pink noise for original speakers and 5 shape variations. The first graph shows all the cases in one graph although it is not easy to see the differences. Therefore the other graphs provide comparisons with the original speaker and the case respectively.

JUST NOTICABLE DIFFERENCE - dB

1.6

1.0 70 Hz

200 Hz

1000 Hz

0.4

100

SOUND PRESSURE LEVEL - DECIBELS Figure 6.7. Just noticeable difference in sound pressure level for three frequencies.

The just noticeable difference (JND) for amplitude is generally from 0.5dB to 1dB (Errede, 2014). It varies depending on the frequency as well as the sound pressure level. Figure 6.7 demonstrates the JND in accordance with two variables. Taking into consideration this JND theory, there are certain changes that should be noticeable through shape alternation because there are some sections indicating a more than 4 dB gap between the two speakers. Case 2 and Case 1 should have the largest differences in theory since they are opposite shapes: 1 is vertically extended and 2 is horizontally extended. Even though the lines seem parallel to each other in the graph 4, there is some fluctuation detected especially in the range of 4,200Hz to 8,500Hz. Case 3, a diamond shape, is very similar to the default (Case 1), and the graph shows the most similarity comparing with Case 1. Case 4, the two diamonds, also resembles Cases 1 and 3 but there are more apparent dissimilarities in the range 870 to 5,500Hz. On the other hand, Case 5, which has a similar shape to Case 2, looks like a combination of the graphs for Cases 2 and 4. The other analysis with the music â&#x20AC;&#x2DC;Summer 78â&#x20AC;? was carried out as well. The results were not very different from pink noise other than the different aspects of the graphs. The biggest differences were found in the comparison with the original speaker and the other cases. Among the comparisons with Case 1, 10dB was the largest gap between cases at 200Hz. Throughout the analysis, what can be said for sure is that the fluctuations between cases should be larger to utilise the shape as an equalizer. The concept is feasible because there are still changes discovered at least more than 1dB in each line and it was also very obvious that the different enclosures greatly influence the quality of sound. However, to solidify the concept, diverse approaches and methods should be investigated more thoroughly for this concept. One of the factors of great 86

influence for the sound alternation is material. According to the SOb project, there has been a series of material recognition tests and the results of Gaverâ&#x20AC;&#x2122;s test describe the performance discriminating between wood and iron bars was almost perfect at 96% to 99% (1988). Moreover, Kunkler-Peck et al (2000)â&#x20AC;&#x2122;s examination of shape and material recognition in struck plates revealed that they succeeded in material distinction almost perfectly. But is material alternation possible with shape simultaneously? As it relates to density of material, if it were a dense variable like polymer-polymer composite, there might be changes. The soft fabric used for the prototype is a dampening material. This affected the results as well. To prevent sound absorbance, thick paper pieces were supplemented but it could lead to unexpected barriers for the experiment since they donâ&#x20AC;&#x2122;t follow the fabric exactly as it moves. This indicates that the outer shape and inner shape are dissimilar so it was not appropriate to detect exact correlations between shape and sound. One of the interesting features that should be not overlooked is that the noise analysis graph with pink noise should have a diagonal line decreasing as it goes to higher frequencies. This might be because of the specifications of the cone and unit since they were not perfect to handle the whole frequency range. The size of the cone is similar to a tweeter type which usually deals with a high frequency range. The other reason for this unexpected graph could be due to the microphone as well. The methods from prototype and post prototype - sound inspection - are very crucial for this project. In theory, people should recognize the sound differences according to prototype variations if JND of sound is taken into consideration. However, to consolidate the concept, it should be developed with feedback from actual listeners not machines. There are four factors to be examined to enhance this project as described above. Because this is just the first trial for the concept, and barriers are inspected, I am convinced that the removal of them will lead to a higher possibility of success for the concept.

Boy and Ox, Vietnam Photograph by Tiong Wee Wong, Your Shot 88

I must confess. I knew little about biomimetics until this year. I had an inkling of how beautiful designs inspired by nature could be after wandering around the ingenious buildings designed by the great architect, Antoni Gaudi in Barcelona, Spain. Even when I chose my dissertation topic, the lasting impression of Gaudi was my main motivation. However the more I explored and dug into biomimetics, the more I realized I was gripped by the field and deeply touched by the fact that our environment is full of infinite wonder. Janine Benyus, an American science writer, innovation consultant and conservationist, says in her 2005 TED talk that biomimicry is an application that mimics an idea from nature and is different from bio-assisted technology using organisms of nature themselves (Benyus, 2007). Even though we have achieved enormous technological advancements, we usually end up with unexpected by-products against circular model of nature and these can become terrifying boomerangs, negatively affecting not only our lives but also those of many other creatures. This is not attributed to a lack of information. This is due to a lack of integration (Janine, 2005.) Nature has already settled on an algorithm suitable for the planet and we just havenâ&#x20AC;&#x2122;t fully appreciated this yet, looking for alternative ways. If all the artificial creations destroying nature could be altered to be environmentally friendly and efficient through biomimetics, and still fulfil all human needs with minimal energy use, the field could accomplish the true meaning of sustainable design. Therefore, it is worth focusing on various areas such as biology, engineering, and design. My biomimetic design is about sensory devices inspired by nature. Following bottomup methods, it begins with extensive research into the work of experts and specialists in auditory design found in nature such as in crickets, cicadas, marine animals and bats. Among these natural precedents I settled on bat ears for their sound interpretation abilities. From the bat studies, it was found that more than 1,000 species are spread over a multitude of environments and each species has evolved ears and noses specially adapted for sensory tasks in particular environments for finding food and other objectives. From the premise that the shape of the receiver pertains to sound function, the concept for the auditory device was created. From market and customer research, it was discovered that the need for high quality audio is generally increasing and sound tastes are just as diverse as people and cultures. Though it started as a mere sound receiver, to meet customer needs and various tastes, the application design concept became a speaker, a sound emitter in which the enclosure acts like an equaliser through shape transformation. After making the working model and the final sound inspection, results showed fluctuations. This suggests that if the four factors of materials, structure, appropriate inner parts like unit, and sound are optimised, the concept can be successfully developed to become a shape equaliser without any complex electric mechanism.

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22.http://www.warrenphotographic.co.uk/photography/bigs/26149-Long-eared-bat-whitebackground.jpg 23. https://askabiologist.asu.edu/sites/default/files/echolocation.jpg 24. http://ngm.nationalgeographic.com/2014/03/bat-echo/img/06-nectar-bats-composite-670.jpg 25. http://iopscience.iop.org/0964-1726/21/9/094025 26. http://iopscience.iop.org/0964-1726/21/9/094025 27. http://www.wondermondo.com/Images/NAmerica/LesserAntilles/Aruba/GuadirikiriCave2.jpg 28. http://www.sciencedirect.com/science/article/pii/S0003682X14001480# 29. http://www.warrenphotographic.co.uk/photography/bigs/04838-Siamese-fighting-fish-whitebackground.jpg 30. http://media.npr.org/assets/img/2014/07/21/ormia-ochracea-fly_slide-2b1ffe803b42fca2be697 372c90339094512779d.jpg 31. http://news.koita.or.kr/rb/files/2014/03/17/ccc72a9fa64861f9c8ce6328a0aea66c150050.jpg 3 2 . h t t p : // i m g 0 1 . l a v a n g u a r d i a . c o m / 2 0 1 2 / 1 2 / 1 1 / P a l a u - d e - l a - M u s i c a - C a t a l a na_54357207493_54028874188_960_639.jpg 33. http://img.hani.co.kr/imgdb/resize/2006/0519/03250480_20060519.JPG 34.http://anthonymbiotask3.wikispaces.com/file/view/Sperm_whale_sound_production. jpg/77267283/293x185/Sperm_whale_sound_production.jpg 3. Primary Research 01. http://www.esm.vt.edu/people/affiliate/r-mueller/S_esm-med-muller.jpg 4. Concept 01. http://www.warrenphotographic.co.uk/photography/bigs/13498-Meadow-Grasshopper-whitebackground.jpg 02.http://cdn.c.photoshelter.com/img-get/I0000ZxJcHYZMaeI/s/880/880/AH-Cicada-BorneoCutout-8999.jpg 03.http://www.warrenphotographic.co.uk/photography/bigs/26149-Long-eared-bat-whitebackground.jpg 04.http://www.sportswarehouse.co.uk/product_images/q/955/rucanor_metal_whistle__30035_ zoom.jpg

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05.http://www.image-tmart.com/images/E/E01138/Emergency-Security-Alarm-LED-StrobeFlashing-Light-Red-02.gif 06. http://www.creativecomputing.net/images/microphone.jpg 07. http://media.engadget.com/img/product/28/m8q/beolab-2-2gfo.jpg 08.http://www.arcor.de/iimages/gimages/VUPbWzbrpUOx53wjRHGEALdyaUnnbg07Sw_ mOPL7Kgo_yJ+xC17i21knDZ+rG_Esjlvg4jtKMO5889bCsWmp_g==.jpg 5. Design 01. http://www.soundobject.org/SObBook/SObBook_JUL03.pdf 02. http://www.soundobject.org/SObBook/SObBook_JUL03.pdf 03. http://www.soundobject.org/SObBook/SObBook_JUL03.pdf 04. http://i.ebayimg.com/00/s/NjAwWDYwMA==/z/WtgAAOxyUrZS3HIL/$_12.JPG 05. http://www.azuremagazine.com/wp-content/uploads/2013/05/Archaeology-Digital-13.jpg 06. http://www.abitare.it/en/wp-content/uploads/2010/11/gina_side2_Gal700px.jpg 07. http://blog.designaffairs.com/wp-content/uploads/2008/07/bmw-gina-light-visionary-model09-lg.jpg 08. https://lh6.ggpht.com/z42uX0rixM_w5qhB1Z-zCLg8R7WhenV7O9CEawWQWmIUe6ia8yL9SD 09ixL_BU7cTOHR_ac=s168 09. http://www.fabricarchitect.com/uploads/2/8/1/0/2810283/2506493_orig.jpg 10. https://armijos.files.wordpress.com/2010/03/as-venafro3.jpg 11. http://www.shelter-systems.com/images/f22.jpeg 12. http://elreta.files.wordpress.com/2011/08/wpid-photo-16082011-21232.jpg 13. http://media-cache-ak0.pinimg.com/236x/b5/3b/aa/b53baa71befd8d7b27671d3d7a643fa9.jpg 14. http://image.architonic.com/imgTre/07_11/textil-snohetta-1.jpg 15.http://www.groschmedaljen.no/sites/default/files/tubaloon_kongsberg_jazzfestival_robert_ sannes.jpg 16. http://static.panoramio.com/photos/large/4637913.jpg 17. http://image.architonic.com/imgTre/07_11/textil-VenPav-2.jpg 18. http://edelscope.files.wordpress.com/2012/06/16.jpg

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19.http://www.laurenceking.com/media/catalog/product/cache/2/image/500x/9df78eab33525d08 d6e5fb8d27136e95/F/o/FoldingTechniques.png 20. http://i1.wp.com/farm1.static.flickr.com/148/430564620_f3127b7005_o_d.jpg?w=450 21. http://3.bp.blogspot.com/-6W9IVKKJt7Y/Tq73bk20hzI/AAAAAAAAAMQ/0c0QCkdo-FE/s1600/ origami-tessellation-1.jpg 22. http://bryantyee.files.wordpress.com/2011/01/dsc_0294.jpg?w=620 23. http://bryantyee.files.wordpress.com/2011/01/dsc_0295.jpg?w=620 24. http://bryantyee.files.wordpress.com/2011/01/dsc_0299.jpg?w=620 25. http://bryantyee.files.wordpress.com/2011/01/dsc_0301.jpg?w=620 26. http://bryantyee.files.wordpress.com/2011/01/dsc_0303.jpg?w=620 27. http://bryantyee.files.wordpress.com/2011/01/dsc_0305.jpg?w=620 28. http://b.fastcompany.net/multisite_files/codesign/slides/in-ei-tr-011-by-issey-miyake-realitylab-6.jpg 29.https://jewellerychina.files.wordpress.com/2012/10/inherence-in-nature-collection2. png?w=580&h=197 30. https://jewellerychina.files.wordpress.com/2012/10/kaleido-7.png?w=580&h=198 31. http://www.patternpeople.com/wp-content/uploads/2013/04/origami-01.jpg 32. http://www.elisastrozyk.de/bilder/woodtex/textiles/woodentextile7.jpg 33. http://www.elisastrozyk.de/bilder/woodtex/textiles/woodentextile13.jpg 34. http://n0-brainer.de/nobrainerblog/wp-content/uploads/2012/08/helmet.jpg 35. http://www.ufunk.net/wp-content/uploads/2012/11/ufunk-selection-du-week-end-9-17.jpg 36. http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/490AAOxyF0pThiga/$_57.JPG 37. http://cdn.instructables.com/F7J/FH9O/F5Y3YRHB/F7JFH9OF5Y3YRHB.MEDIUM.jpg 6. Evaluation 01. http://www.glkinst.com/cmetersoftware/LabVIEWScreenShots/image001.png 02. http://www.mathworks.com/help/rptgen/ug/figloop_tut_mfile.gif 03. http://mansquito.com/storyimages/pinkNoiseGraph.png

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Semi cover images from National Geographic 01.http://images.nationalgeographic.com/wpf/media-live/photos/000/589/cache/lizard-parkcuba_58927_990x742.jpg 02.http://images.nationalgeographic.com/wpf/media-live/photos/000/086/cache/smiths-greeneyed-gecko_8627_990x742.jpg 03.http://images.nationalgeographic.com/wpf/media-live/photos/000/720/cache/panther-zooflorida-sartore_72061_990x742.jpg 04.http://images.nationalgeographic.com/wpf/media-live/photos/000/456/cache/verreauxsifaka-madagascar_45685_990x742.jpg 05.http://images.nationalgeographic.com/wpf/media-live/photos/000/565/cache/peacockfeathers-florida_56547_990x742.jpg 06.http://images.nationalgeographic.com/wpf/media-live/photos/000/720/overrides/alligatorokefenokee-swamp-farlow_72098_990x742.jpg 07.http://images.nationalgeographic.com/wpf/media-live/photos/000/199/cache/boy-oxvietnam_19998_990x742.jpg

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APPENDIX Viva Presentation (17. 07. 2014)

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Shape Variations through CAD

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Drawings for prototype structure

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Frame Variations

A type

B type

Two frame shapes were 3d printed before making whole structures. Since A type has more strengths than B type, A type was finally chosen.

Diverse Pattern Trials

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Sound test result with music ‘Summer 78’

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