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*
Richard Cytowic (2003) explains synesthesia as “a stimulation of one sensory modality automatically triggers perception in a second modality in the absence of any direct stimulation to this second modality” in his article named “Synesthesia: A Union of Senses”. The individuals who are experiencing synesthesia are called synesthetes. (Cytowic, 2003) According to Deni Simon, a synesthete, interviewed by Cytowic, (2003) music causes audial waveforms visually. “Like oscilloscope configurations, lines moving in color, often metallic with height, width and, most importantly, depth. My favorite music has lines that extend horizontally beyond the screen area.” he mentions when explaining
his unique experience of synesthesia.
V OL U ME 1:
DISC L OSU RE ALI CAN IN A L YAN Z H ON G L I YU GE |3
September 2017
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Deepest thanks to Roberto Bottazzi and Kostas Grigoriadis, for their endless efforts and stimulating guidance.
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1
INTRODUCTION The Site 07 Introduction to Sound 11
2
E X C AVAT I N G T H E C U R R E N T S O U N D S C A P E Sound Data Visualisations 21 Correlations and Cross-Reading the Data 55 Nature of Sound (How Sound Propagates?) 62 Urban Sound Simulations 66
3
M AT E R I A L S T U D I E S Introduction to Sound/Matter Relationship 90 Initial Material Experiments 94 D.I.Y. Sound Absorbsion/Reflection Measuring Device 102 Digital Material Simulations 108
4
S O N I C C RY S TA L A R R AY S [A Metamaterial Approach to Sound] Introduction to Metamaterials 130 Sonic Crystal Arrays 132 Digital Sonic Crystal Array Simulations 134 D.I.Y. Sonic Crystal Array Testing Device 136
5
INITIAL PROPOSALS FOR AN URBAN INTERFACE Fluid Crystal Array 146 Sound Structures 175 Sound-driven Moving Panels 187 Modular Crystal Array 195
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VOLUME 1: DISCLOSURE
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1 I NT ROD U C T ION Our city is an enormous complex of all different kinds of information and data. The more effecient you use the data, the more you will understand about the city. In this project, sound is used as a method to explore the role of big data in urban design, and ananlyse the city environment, trying to redefine the relationship between urban spaces and sound.
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SITE
INTR O DUC TIO N
OVERALL Stratford is a district in the London Borough of Newham, in East London, England. Historically an agrarian settlement in the county of Essex, it was transformed into an industrial suburb following the introduction of the railway in 1839. The late 20th Century was a period of severe economic decline, eventually reversed by regeneration associated with the 2012 Summer Olympics, for which Stratford’s Queen Elizabeth Olympic Park was the principal venue. Stratford is now East London’s primary retail, cultural and leisure centre. It has also become the second most significant (after Canary Wharf) business location in the east of the capital. Queen Elizabeth Olympic Park aims to become a global centre of international distinction, a thriving new metropolitan district in London, and an anchor in the social and economic regeneration of east London. It will be a place unlike any other in London, offering the best in sporting and cultural amenities in world-class venues and parks, and at the same time creating places to live that are rooted in the ethos and fabric of east London’s diverse and vital communities. Hackney Wick is an area of east London in the London Borough of Hackney, adjacent to the boundary with Old Ford in the district of Bow in the London Borough of Tower Hamlets. It is an inner-city development situated 5 miles (8 km) northeast of Charing Cross. It is in the far east of the borough and at the southern tip of Hackney Marshes and includes part of 2012 Olympic Park west of the River Lea, (traditionally the boundary between Middlesex and Essex) and forms part of the Lower Lea Valley.
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S I T E
HI S TORY
1900-1990 Prosperity to Decline The Bow Back Rivers are a 16km (10mile) system of
In the early 1930s major investment was injected
waterways which feed into the River Lee Navigation and
into the Bow Backs to improve their ability to
the Thames in east London. The recorded history of the
accommodate both floodwaters and navigation.
rivers dates back to Alfred the Great and the invasion of
Waterworks River was significantly modified and two
the Danes when the River Lea was the border between
new locks constructed at City Mills and Carpenters
England and Danelaw.
Road.
Carpenters Road Lock
Three Mills Wall River
Old Ford Lock
1930s Stratford Plan
River Lee
City Mill River
1990-2005 ‘Remainder’ Waterways The potential importance of the Bow Backs began to be reognised in the early 1990s when regeneration initiatives around Stratford started to emerge. In particular, the establishment of the Channel Tunnel Rail Link began the transformation in people’s attitudes towards this little known part ofLondon.
Built environment at 2003
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Waterworks River
2005-2012 Creating World Class Waterways In a short six-year period between 2005 and 2012
The catalyst was the construction of a new lock and
more than ÂŁ50m of investment was made by various
water control structure at Three Mills which has
Government agencies to transform the waterways of prevented tidal inundation into the Park, turning a the Lower Lea Valley.
5.6km length of steep-sided flood relief channel, with a tidal range between zero ordnance datum to over four metres, into a navigable watercourse integrated with the newly regenerated waterside, parklands, wetlands and wildlife areas.
Wetland plainting on the River Lee
Built environment at 2012
Construction of Three Mills Lock
Built environment at 2015
City Mill River and the River Lea
2012- London Olympic and Paralympic Games Millions of people visited the Park during the period of
From the moment David Beckham appeared on
the London 2012 Olympic and Paralympic Games which
board a speed boat on Waterworks River to hand
provided a valuable insight into how people used and
over the Olympic Torch as part of the Opening
enjoyed the Park and its waterways. The water clearly
Ceremony, to seeing how people made use of
had a magnetising effect not just on visitors but also on
the river towpaths and grassed banks to find a
those watching on television.
relaxing retreat from the crowded spaces around the sporting venues, it is clear to see how the waterways can play an important role in the future development and offer of the Park.
Waterworks River
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SO UND
INTR O DUC TIO N
Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an acoustician, while someone working in the field of acoustical engineering may be called an acoustical engineer. An audio engineer, on the other hand, is concerned with the recording, manipulation, mixing, and reproduction of sound. Hearing is one of the most crucial means of survival in the animal world, and speech is one of the most distinctive characteristics of human development and culture. Accordingly, the science of acoustics spreads across many facets of human society—music, medicine, architecture, industrial production, warfare and more. Likewise, animal species such as songbirds and frogs use sound and hearing as a key element of mating rituals or marking territories. Art, craft, science and technology have provoked one another to advance the whole, as in many other fields of knowledge.
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O V E R V I E W
From a very fundamental level, the acoustic environment can be broken down into three elements: the source, the path, and the receiver. The source is the thing which is producing sound- a human, a bird, a speaker, etc. The path is the medium though which the sound transmits- this may be the air or it could be the structure of a building. The reciever may be a listener or a microphone. If a sound source is considered undesirable, then the design objective is to reduce the ability for that the sound to reach the receiver. This may be accomplished by creating distance between source and reciever or manipulating the environment or path to attenuate or transfer the sound. If a sound source is considered desirable, such as music or speech, then the design objective is to maintain clarity or enhance the sound source so that it is clearly received and not distorted or degraded by the environment. In physical terms, a sound is mechanical wave that propagates through some medium ( solid, liquid, gas) by way of compression and rarefaction of molecules in
amplitude
that medium. In the air, the results in microscopic changes in the local atmospheric rarefaction
pressure. The rate of the changes in pressure in one second constituted the frequency, expressed in Hertz (Hz). The amount of change in pressure constitutes the amplitute, expressed using the logarithmic decibel (dB) scale. All sound possess these fundamental properties of frequency (what we my perceive as pitch) andamplitude (what we may perceove as loudness).
compression wavelength
SO UND
PROPERTI ES
Sound is a mechanical wave that propagates through air by way
FREQUENCY
of compression and rarefaction of molecules. The rate of change
An audio frequency (abbreviation: AF) or audible frequency is characterized as a
constitutes frequency [Hz]. The amount of change in pressure
periodic vibration whose frequency is audible to the average human. Frequency can
constitutes amplitude [dB].
be described in terms of wavelength, the spatial distance over which the wave’s shape repeats itself. The lowest frequency we can hear (20 Hz) has a wavelength of roughly 17 metres, whereas the highest frequency we can hear (20,000 Hz) has a wavelength of 0.02 metres, It is important to understand wavelength because the dgree to which an object or surface interacts with sound is dependent upon its dimensions in relation to wavelength. For example, absorption performance is directly related to the thickness
threshold of pain threshold pain
of material om relation to wavelength. Wavelength can be calculated using the
SOUND PRESSURE LEVEL [dB]
120
following simple equation: audible range of hearing
100
wavelength = speed of sound [c] / frequency [Hz] music
80
SOUND SPEED
60
The speed of sound is the distance travelled per unit time by a sound wave as it
speech
propagates through an elastic medium. The speed of sound varies dramatically according to the elasticity and density of the medium. In air, the speed of sound can
40
change according to tempreture and humidity but is generally considered to be around
20
343 metres per second (or 1125 feet per second). And the speed of sound varies from threshold of hearing
substance to substance: sound travels most slowly in gases; it travels faster in liquids;
0 20
50
100
200
500
1k
2k
5k
10k 20k
FREQUENCY [Hz]
and faster still in solids. For example, (as noted above), sound travels at 343 m/s in air; it travels at 1,484 m/s in water (4.3 times as fast as in air); and at 5,120 m/s in iron. In an exceptionally stiff material such as diamond, sound travels at 12,000 m/s; which is around the maximum speed that sound will travel under normal conditions. Sound
The audible range of hearing is shown overlaid with the typical
waves in solids are composed of compression waves (just as in gases and liquids), and
ranges for music and human speech sounds. The ear does not hear
a different type of sound wave called a shear wave, which occurs only in solids. Shear
all frequencies equally and si less sensitive to very low frequencies,
waves in solids usually travel at different speeds, as exhibited in seismology. The
below 100 Hz.
speed of compression waves in solids is determined by the medium's compressibility, shear modulus and density.
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SOUND DECIBEL The decibel is commonly used in acoustics as a unit of sound pressure level. The reference pressure for sound in air is set at the typical threshold of perception of an average human and there are common comparisons used to illustrate different levels of sound pressure. Sound pressure is a field quantity, therefore the field version of the unit definition is used:
Lp = 20 log10 (prms/pref) dB, where pref is the standard reference sound pressure of 20 micropascals in air or 1 micropascal in water. The human ear has a large dynamic range in sound reception. The ratio of the sound intensity that causes permanent damage during short exposure to that of the quietest sound that the ear can hear is greater than or equal to 1 trillion. Such large measurement ranges are conveniently expressed in logarithmic scale: the base-10 logarithm of 1012 is 12, which is expressed as a sound pressure level of 120 dB re 20 μPa. Since the human ear is not equally sensitive to all sound frequencies, noise levels at maximum human sensitivity, somewhere between 2 and 4 kHz, are factored more heavily into some measurements using frequency weighting.
130
(estimated)
120 110
Reverberation is the persistence of sound after a sound is produced. A reverberation,
100
or reverb, is created when a sound or signal is reflected causing a large number of
90
reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space – which could include furniture, people, and air. This is most noticeable when the sound source stops but the reflections continue, decreasing in amplitude, until they reach zero amplitude. Reverberation is frequency dependent: the length of the decay, or reverberation time, receives special consideration in the architectural design of spaces which need to have specific reverberation times to achieve optimum performance for their intended
Sound Pressure Level (dB SPL)
REVERBERATION
70 50
40
40 30
20
20 10
initial sound, reverberation is the occurrence of reflections that arrive in less than
-10
forests and other outdoor environments where reflection exists.
60
60
0
until it is reduced to zero. Reverberation is not limited to indoor spaces as it exists in
80
80
activity. In comparison to a distinct echo that is a minimum of 50 to 100 ms after the approximately 50 ms. As time passes, the amplitude of the reflections is reduced
100phon
(threshold)
10
100
1000
10k
100k
Equal-loudness contours (red) (from ISO 226: 2003 revision) Original ISO standard shown (blue) for 40-phons
Reverberation occurs naturally when a person sings, talks or plays an instrument acoustically in a hall or performance space with sound-reflective surfaces.The sound of reverberation is often electronically added to the vocals of singers in live sound systems and sound recordings by using effects units or digital delay effects.
This graph, courtesy of Lindosland, shows the 2003 data from the International Standards Organisation for curves of equal loudness determined experimentally. Plots of equal loudness as a function of frequency are often generically called Fletcher-Munson curves after the original work by Fletcher,
REVERBERATION TIME The metric 'reverberation time' (RT) is defined as the amount of time it takes for the
H. and Munson, W.A. (1933) J.Acoust.Soc.Am. 6:59. You can make your own curves using our hearing response site.
sound pressure level to decrease by 60 dB after the sound source has stopped. RT = k*V / A Reverberation time is related to the total volum of the room and the total absorption
RT = reverberation time (seconds)
in the room, which was discovered at the beginning of the 20th century by Wallace
k = constant (0.161 for metric; 0.049 for imperial)
Clement Sabine. The Sabine equation is still useful to this day for making rough
V = room volume (m3 or ft3)
predictions:
A = total surface absorption - the sum of the surface area of each material (m2 or ft2) multiplied by the material's absorption coefficient (α)
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The sound we hear are typically a complex mixture of many frequencies at different amplitudes which are varying over time. When taking acoustical measurements or conducting calculations, for the purpose of simplification, it is common to divide the frequency spectrum into 1/3 octave bands or 1/1 octave bands. Acoustic materials are commonly measured in 1/3 octave band resolution and then simplified into 1/1 octave
nd
bands or single number metrics.
so u
absorbed sound
re
fle
ct e
d
the complexity of texture may cause a sound to reflect more diffusely, while a flat,
angle of reflection angle of incidence
transmitted sound
di
In concert with material, sound is also influenced by form. At the scale of surface, monolithic surface will reflect specularly. This interaction is also dependent upon the sound's wavelength in ralation to the dimensions of the surface patterning. A diffuse reflection scatters the sound in various directions, avoiding repetitive reflections between parallel surfaces and resulting in a sound field that is more homogeneous.
re
ct
so
Baroque architecture, with ornate finishes and sculptures, often results in diffuse
un
d
sound environments. Smoth surfaces shaped into concave parabolic forms can focus sound into beams, amplifying and transmitting that sound a grater distance. This is often experienced in 'whisper-galleries' where the sound of a whisper seems to cling to theedge of a wall and reappear elsewhere. Smooth conves forms will scatter or diffuse sound reflections.
When sound strikes a material, a fraction of energy is absorbed, reflected, and transmitted through. Fpr flat surfaces, the angle of reflection will equal the angle of incidence.
RESONANCE Natural frequency is the frequency at which a system tends to oscillate in the absence of any driving or damping force. Free vibrations of an elastic body are called natural vibrations and occur at a frequency called the natural frequency. Natural vibrations are different from forced vibrations which happen at frequency of applied force (forced frequency). If forced frequency is equal to the natural frequency, the amplitude of vibration increases manyfold. This phenomenon is known as resonance. When surfaces come together to create a sense of enclosure, sound is supported, amplified, and filtered through the phenomenon of resonance. A resonance is a tendency for certain frequencies to be emphasized due to the volume, form, and material conditions of a space. Rsonances occur at various spatial scales. When we blow across the top of an empty glass bottle, we excite its resonant frequency. In small rooms, these resonances are often referred to as modes, which occur at very low frequencies. Room modes pose problems in recording studios because the resonances can cause some low frequencies to be unusually loud and others to be unusually quiet.
M AT ERI AL
A P P L I C AT I O N
Sound absorbing material can be used for a variety of practical applications, namely to reduce noise level in an enclosed space, to reduce reverberation, to eliminate echoes, and to improve speech intelligibility. These applications can dramatically influence our perception of our environments, which we may decribe as clear or muddy; lively or dead; bright or dark; dry or wet; intimate or spacious; rich or thin; coherent or incoherent; harmonious or discordant. The sound we perceive consist of both the direct sound from the source as well as the reflections from the objects and surfaces in our environment. When these sounds combine at our ears, they tell us not only about the source but also the environment Diagrams showing the different ways in which the form of a surface
or context with which the source and reciever are placed. The reflections from the
can cause influence sound reflection. Convex and ornate surfaces will
objects and materials in our environment is wht our voice sounds different singing in
cause sound to scatter, flat surfaces cause specular reflections, and
the shower compared to outdoors.
concave surfaces cause focusing.
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In a free-feild where there are no sound reflecting surfaces, only the direct sound is received and sound spreads out spherically from the source. In these conditions, the sound level will decrease by 6 dB for every doubling of distance between the source and receiver. In most environments, particularly indoors, there areobjects and surfaces which reflect sound and these reflections can add to the total sound level received. In a reverberant environment, sound may behave under free-feild conditions when very close to the sound source (typically less than 2 metres) but the reverberant field will dominate at greater distances, By adding sound absorption to a room, the reflections from the room surfaces can be reduced or eliminated so that primarily the direct sound is heard. The reflections that make up the reverberant field will add to the total level of sound. By adding absorptive materials to reverberant space, you can reduce the reverberant reflections and thereby reduce the overall sound levels within a space. For each doubling of the total amount of absorption in a room, the sound level can be reduced by 3 dB. The following simple formula can be used to predict the reverberant sound level reduction by comparing the total absorption in the room before and after absorbing materials have been added. noise reduction [dB] = 10*log total room absorption
total room absorption
after treatment [sabins] / before treatment [sabins] For the most situations, the upper limit of this noise reduction is 10 dB, which perceptually would sound like a 50 percent reduction in the total sound level. In noisy environments, humans tend to involuntarily increase their vocal effort to be heard over the background noise. This is referred to as the Lombard Effect and can be experienced first hand in any loud restaurant or bar. Reducing reverberant noise can helo avoid situations where the Lombard Effect occurs. Reducing sound reflections is desirable for a number of other reasons: reflections can make speech unintelligible, they can make it difficult to locate where sounds are coming from, and they can make music sound muddy. On the other hand, if there aren't enough reflections, a space can feel too dry, quiet or dead, so delicate balance must be achieved. The intelligibility of speech is dependent upon a number of factors that include the distance between the source and reciever, the loudness of the sounrce compared to the background noise level,and the amount of reverberation in the environment. Reverberation impacts intelligibility in two ways, it raises the overall background noise level and the late arriving reflections cause language to become distorted or blurred. Sound absorbing materials are used in all manner of spaces where speech intelligibility is crucial: classrooms,courtrooms, lecture halls, and public spaces where announcements from emergency and public address systems must be clearly understood. Sound absorbing materials are also used to address very specifc types of sound reflections which are often problematic, such as focusing that occurs from a concave surface or echoes, which are reflections delayed in time and perceived as separate from the original sound source. Echoes can occur from flat surfaces located 15 metres or more from the sound source.
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SP E C T R O G R A M A spectrogram is a visual representation of the spectrum of frequencies in a sound or other signal as they vary with time or some other variable. Spectrograms are sometimes called spectral waterfalls, voiceprints, or voicegrams. Spectrograms can be used to identify spoken words phonetically, and to analyse the various calls of animals. They are used extensively in the development of the fields of music, sonar, radar, and speech processing, seismology, etc.
8
A common format is a graph with two geometric dimensions: the horizontal axis
There are many variations of format: sometimes the vertical and horizontal axes are switched, so time runs up and down; sometimes the amplitude is represented as the height of a 3D surface instead of color or intensity. The frequency and amplitude axes can be either linear or logarithmic, depending on what the graph is being used for. Audio would usually be represented with a logarithmic amplitude axis (probably in decibels, or dB), and frequency would be linear to emphasize harmonic relationships, or logarithmic to emphasize musical, tonal relationships.
Frequency (kHz)
or color of each point in the image.
-10
6
represents time or rpm, the vertical axis is frequency; a third dimension indicating the amplitude of a particular frequency at a particular time is represented by the intensity
+0
7
FORMAT
-20
5
-30
4
-40
3
-50
2
-60 1 DC
0 2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Time(s)
Spectrograms are usually created in one of two ways: approximated as a filterbank that results from a series of band-pass filters (this was the only way before the advent of modern digital signal processing), or calculated from the time signal using the Fourier transform. These two methods actually form two different time–frequency representations, but are equivalent under some conditions. The bandpass filters method usually uses analog processing to divide the input signal into frequency bands; the magnitude of each filter's output controls a transducer that records the spectrogram as an image on paper.
GENERATION Creating a spectrogram using the FFT is a digital process. Digitally sampled data, in the time domain, is broken up into chunks, which usually overlap, and Fourier transformed to calculate the magnitude of the frequency spectrum for each chunk. Each chunk then corresponds to a vertical line in the image; a measurement of magnitude versus frequency for a specific moment in time (the midpoint of the chunk). These spectrums or time plots are then "laid side by side" to form the image or a
Spectrogram of this recording of a violin playing. Note the harmonics
three-dimensional surface, or slightly overlapped in various ways, i.e. windowing. This
occurring at whole-number multiples of the fundamental frequency. Note
process essentially corresponds to computing the squared magnitude of the short-
the fourteen draws of the bow, and the visual differences in the tones.
time Fourier transform (STFT) of the signal s(t) — that is, for a window width w, spectrogram(t, w) = | STFT (T,W) |2
APPLICATION Early analog spectrograms were applied to a wide range of areas including the study of bird calls (such as that of the great tit), with current research continuing using modern digital equipment and applied to all animal sounds. Contemporary use of the digital spectrogram is especially useful for studying frequency modulation (FM) in animal calls. Specifically, the distinguishing characteristics of FM chirps, broadband clicks, and social harmonizing are most easily visualized with the spectrogram. Spectrograms are useful in assisting in overcoming speech defects and in speech training for the portion of the population that is profoundly deaf. The studies of phonetics and speech synthesis are often facilitated through the use of spectrograms.
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3D surface spectrogram of a part from a music piece.Â
-70 dBFS
EXAMPLE RT CALCULATION An example reverberation time(RT) calclulation using the Sabine equation iS Presented here for two simple scenarios: a highIy reverberation room (gypsum,concrete and glass finishes) and the same room with fibreglass added to the ceiling and thin carpet added to the floor.The room is 5 metres long, 4 metres Wide, and 3 metres tall, resultlng in a total room Volume of 60 m3. For each room, tables are provided with the absoption coefficients for each surface material in octave bands. The surface area of the material is then multiplied by the absorption coefficient and this is summed together to give the total absorption within the room. In the last row, the RT is then calculated for each octave band. If this room were being designed as a conference room,the criteria chart on the preceding page would suggest that a room of 60 m3 should have a reverberation time of around 0.5 seconds at 500 Hz.The untreated room is indicating a reverberation time of 2.9 seconds at 500 Hz. Once fibreglass and thin carpet are added to the room, the reverberation time drops significantly. Using the formula presented in the preceding section, it is also possible to estimate the anticipated noise reduction due to the addition of absorptive materials. This formula compares the total absorption of the before and after conditions. For example, looking at the 500 Hz octave band, the before condition had a total sabins value of 3.4 and after adding absorption that value increased to 24.2. The reverberant noise reduction is anticipated to be 8.5 dB. noise reduction [dB] = 10 * log (24.2/3.4) = 8.5 dB It is interedting to note that the untreated room has very short reverbretion times at low frequencies (less than 1 second at 125 Hz). This occurs because gypsum and glass
3 metres
are somewhat absoptive at 125 Hz.
es
etr
4m
5 metres An untreated, 60 m3 reverberant room with concrete floor, and ceiling, 3 gypsum walls, and 1 glass wall. Using the Sabine
3 metres
equation, the reverberation time at 500 Hz is 2.9 seconds.
s
tre
e 4m
5 metres When fibreglass panels are mounted to the ceiling and thin carpet is installed on the floor of the same 60 m3 room, the reverberation time at 500 Hz drops to 0.4 seconds.
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2 EX CAVAT ING
T H E
C U RRE NT S OU ND S C APE Sound as a invisible element is usually used to be ignored by people, but sound affects a lot in daily life imperceptibly. Using the way of computational simulation, sound could be easier to eveluate. In this section, points are selected to measure the decibel and frequency level, and it could be helpful to understand the sound environments at the site.
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SO UND
DATA
V ISUA L IZATI ON
Sound as a invisible element is usually used to be ignored by people, but sound affects a lot in daily life imperceptibly. Using the way of computational simulation, sound could be easier to eveluate. In this section, 429 points, 200x200 grid, recording each point for 1 minute, are selected to measure the decibel and frequency level, and it could be helpful to understand the sound environments at the site. In this part, Adobe Audition, which is used to analyzed the sound decibel and frequency, also generates the spectrogram. The spectrogram shows the sound environments in a clear way by using various colours. And space syntax also makes sense in elevating the accessibilities about site. Real flow simulates the sound particle in a smaller scale.
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P O I N T
BA S E D
ON - S I TE
R E C O R DING S
AVERAGE FREQUENCY MAP On-site recordings were made in 420 individual points within the Queen Elizabeth Olympic Park. The primary outcome of the recordings were decibel and frequency values, which will be the basic datas to lead the research to further phase. Frequency particularly, is the key value to understand the physical nature of sound. Therefore, the topography created from the frequency map is the primer phase of an actual visible sound environment.
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AVERAGE DECINELS MAP On-site recordings were made in 420 individual points within the Queen Elizabeth Olympic Park. The primary outcome of the recordings were decibel and frequency values, which will be the basic datas to lead the research to further phase. The average decibels map clearly reveals the relationship between noise sources and their impact ranges. Also it distinctly creats further potentials of research and design.
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MAXIMUM DECIBELS MAP On-site recordings were made in 420 individual points within the Queen Elizabeth Olympic Park. The primary outcome of the recordings were decibel and frequency values, which will be the basic datas to lead the research to further phase. The maximum decibels map clearly reveals the ranges of noise sources and their impact bounds. Also it distinctly creats further potentials of research and design.
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MINIMUM DECIBELS MAP The minimum decibels map clearly reveals the ranges of noise sources and their impact bounds. Also it distinctly creats further potentials of research and design.
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SP E C T R O GR A M FULL-SITE SPECTROGRAM The diagram shows all the spectrogram which comes from 429 points in site.
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3D SPECTROGRAM FOR FIVE RECORDING POINTS
The 3d spectrograms show sound environments about 6 points, T42, U42, V42, T43, U43, V43.
FRONT VIEW
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SIDE VIEW
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SO U N D C I T Y If the sound is visible in daily, how it will look like. The sound waves look like the mountains, and also could be considered as habitat.
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ROA D S
A N D
AC CE S S I BI L I T Y
SPACE SYNTAX Space syntax shows the accessibilities of the site.
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INTEGRATION R1600
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R O A D N O I S E A N A LY S I S The road noise maps reveal the noise level in day and night time.
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3D SOUND MODEL
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SOUND DECIBEL ZONES
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CR O S S
C OR R E LAT I ON S
MAXIMUM/MINIMUM AMPLITUDE RANGE Through the search of induvidual focus areas, both the minimum ans maximum amplitude values were used to determine high range decibel differences in the site. These sites have unstablenoise patterns and rough changes in the peak and button decibel flows.
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DECIBEL STRATUMS Through the search of induvidual focus areas, both the minimum ans maximum amplitude values were used to determine high range decibel differences in the site. These sites have unstablenoise patterns and rough changes in the peak and button decibel flows.
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NATURE OF SOUND (HOW SOUND PROPAGATES)
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LO C A L
S I M U L AT I ON S
ANATHOMY OF A POINT
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SOUND PROPAGATION IN LIQUIDS
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SOUND PROPAGATION IN LIQUIDS
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SOFAR CHANNEL
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INTE R I O R
S OU N D S CA P E S
The sound visualization system could be applied even is our daily life. this is a try-out in the studios of Bartlett School of Architecture.
PERSPECTIVE VIEW
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SIDE VIEW
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PERSPECTIVE VIEW
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PERSPECTIVE VIEW
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AL E RT I N G
PAVI L I ON
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3 MAT E RIAL S T U D IE S When a conceptual design comes out, a particular material is an enssitial element to be found out especially for the sound which is a type of invisible components. A plethora of materials can be transformed into sound absorbed by the simple act of perforation - woods, plastics, metals, and stones. While perforation has been understood for many decades, there continues to be room for innovation and digital fabrication technologies are making the process of customization, prototyping, and fabrication easier, more costeffective, streamlined, and elaborate.
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MATE R IA L
STUDIE S
When a conceptual design comes out, a particular material is an enssitial element to be found out especially for the sound which is a type of invisible components. A plethora of materials can be transformed into sound absorbed by the simple act of perforation - woods, plastics, metals, and stones. While perforation has been understood for many decades, there continues to be room for innovation and digital fabrication technologies are making the process of customization, prototyping, and fabrication easier, more costeffective, streamlined, and elaborate. The material studies could definitely make the design progress and during the material studies wax, foam, steel, concrete, etc have been experimented with the influence of sound. Moreover, except the physical experiments the computational simulations have been carried out at the same time. All of these studies promote the proposal in the following urban interface section.
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INTR ODUC T I ON
PHYSICS
floors, and ceilings. Such chambers are often built as spring
In amplifier and loudspeaker design electrical impedances,
There are three fundamental interactions when a sound
supported isolated rooms within a larger building. Research
mechanical impedances, and acoustic impedances of the
impinges upon a material: some energy is reflected back, some
Council in Canada has a modern anechoic chamber, and has
system have to be balanced such that the frequency and phase
energy is absorbed into the material (converted into a small
posted a video on the Web, noting these as well as other
response least alter the reproduced sound across a very
amount of heat), and some energy my be transmitted through
constructional details. Doors must be specially made, sealing
broad spectrum whilst still producing adequate sound levels
the material to the other side. All material absorb, reflect and
for them must be acoustically complete (no leaks around the
for the listener. Modelling acoustical systems using the same
transmit sound in their own particular way.
edges), ventilation (if any) carefully managed, and lighting
(or similar) techniques long used in electrical circuits gave
chosen to be silent.
acoustical designers a new and powerful design tool. Modelling acoustical systems using the same (or similar) techniques long
Reflection: When a longitudinal sound wave strikes a flat surface, sound is
The second requirement follows in part from the first and
used in electrical circuits gave acoustical designers a new and
reflected in a coherent manner provided that the dimension of
from the necessity of preventing reverberation inside the
powerful design tool.
the reflective surface is large compared to the wavelength of
room from, say, a sound source being tested. Preventing
the sound.
echoes is almost always done with absorptive foam wedges
Soundproofing is any means of reducing the sound pressure
on walls, floors and ceilings, and if they are to be effective at
with respect to a specified sound source and receptor. There
Absorption (Attenuation) Coefficient:
low frequencies, these must be physically large; the lower
are several basic approaches to reducing sound: increasing the
describes the extent to which the radiant flux of a beam is
the frequencies to be absorbed, the larger they must be.
distance between source and receiver, using noise barriers to reflect or absorb the energy of the sound waves, using damping
reduced as it passes through a specific material. An anechoic chamber must therefore be large to
structures such as sound baffles, or using active antinoise
Absoption Class:
accommodate those absorbers and isolation schemes, but
sound generators.
categorizes absorption performances into five classes, where
still allow for space for experimental apparatus and units
Class A has the highest performance.
under test.
Acoustic absorption refers to the process by which a material,
Communication and Concentration in balance:
the sound within a room (See anechoic chamber), and reduce
structure, or object takes in sound energy when sound
Employees are an important company asset and the
sound leakage to/from adjacent rooms or outdoors. Acoustic
waves are encountered, as opposed to reflecting the energy.
provision of a comfortable, attractive working environment
quieting, noise mitigation, and noise control can be used to
Part of the absorbed energy is transformed into heat and
is very important. Acoustically, areas should allow effective
limit unwanted noise. Soundproofing can suppress unwanted
part is transmitted through the absorbing body. The energy
communication between co-workers without being intrusive,
indirect sound waves such as reflections that cause echoes
transformed into heat is said to have been ‘lost’.
a balance between communica- tion and concentration.
and resonances that cause reverberation. Soundproofing can
OWAtecta® ceilings can be used as a key element in the
reduce the transmission of unwanted direct sound waves
When sound from a loudspeaker collides with the walls
design of an efficient workspace providing acoustic control,
from the source to an involuntary listener through the use of
of a room part of the sound’s energy is reflected, part is
a range of versatile systems and the ability to integrate
distance and intervening objects in the sound path.
transmitted, and part is absorbed into the walls. As the waves
services within the ceiling plane. As an introduction we
travel through the wall they deform the material thereof (just
explain below some of the acoustic terms you may encounter.
Two distinct soundproofing problems may need to be considered when designing acoustic treatments - to improve
like they deformed the air before). This deformation causes mechanical losses via conversion of part of the sound energy
The energy dissipated within a medium as sound travels
into heat, resulting in acoustic attenuation, mostly due to the
through it is analogous to the energy dissipated in electrical
wall’s viscosity. Similar attenuation mechanisms apply for the
resistors or that dissipated in mechanical dampers for
air and any other medium through which sound travels.
mechanical motion transmission systems. All three are
The fraction of sound absorbed is governed by the acoustic
equivalent to the resistive part of a system of resistive and
impedances of both media and is a function of frequency and
reactive elements. The resistive elements dissipate energy
the incident angle.[1] Size and shape can influence the sound
(irreversibly into heat) and the reactive elements store and
wave’s behavior if they interact with its wavelength, giving rise
release energy (reversibly, neglecting small losses). The
to wave phenomena such as standing waves and diffraction.
reactive parts of an acoustic medium are determined by its bulk modulus and its density, analogous to respectively an
Acoustic absorption is of particular interest in soundproofing.
electrical capacitor and an electrical inductor, and analogous
Soundproofing aims to absorb as much sound energy (often in
to, respectively, a mechanical spring attached to a mass.
particular frequencies) as possible converting it into heat or transmitting it away from a certain location.
Note that since dissipation solely relies on the resistive element it is independent of frequency. In practice however
In general, soft, pliable, or porous materials (like cloths) serve
the resistive element varies with frequency. For instance,
as good acoustic insulators - absorbing most sound, whereas
vibrations of most materials change their physical structure
dense, hard, impenetrable materials (such as metals) reflect
and so their physical properties; the result is a change
most.
in the ‘resistance’ equivalence. Additionally, the cycle of compression and rarefaction exhibits hysteresis of pressure
An acoustic anechoic chamber is a room designed to absorb
waves in most materials which is a function of frequency, so
as much sound as possible. The walls consist of a number of
for every compression there is a rarefaction, and the total
baffles with highly absorptive material arranged in such a way
amount of energy dissipated due to hysteresis changes with
that the fraction of sound they do reflect is directed towards
frequency. Furthermore some materials behave in a non-
another baffle instead of back into the room. This makes the
Newtonian way, which causes their viscosity to change with
chamber almost devoid of echos which is useful for measuring
the rate of shear strain experienced during compression
the sound pressure level of a source and for various other
and rarefaction; again, this varies with frequency. Gasses
experiments and measurements.
and liquids generally exhibit less hysteresis than solid materials (eg, sound waves cause adiabatic compression and
Anechoic chambers are expensive for several reasons and are
rarefaction) and behave in a, mostly, Newtonian way.
therefore not common. Combined, the resistive and reactive properties of an acoustic They must be isolated from outside influences (eg, planes,
medium form the acoustic impedance. The behaviour of
trains, automobiles, snowmobiles, elevators, pumps, ...; indeed
sound waves encountering a different medium is dictated
any source of sound which may interfere with measurements
by the differing acoustic impedances. As with electrical
inside the chamber) and they must be physically large. The
impedances, there are matches and mismatches and energy
first, environmental isolation, requires in most cases specially
will be transferred for certain frequencies (up to nearly 100%)
constructed, nearly always massive, and likewise thick, walls,
whereas for others it could be mostly reflected.
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FOAM
FOAL AND STEEL
Foam: A foam is a substance that is formed by trapping pockets of gas in a liquid or solid. Foam can be categorized as either open-cell or closed-cell strutures. With closed-cell foams, the gas forms discrete pockets that are fully surrounded by material. In opencell foams, the gas pockets create an interconnected network of cavities. FOAM
AND
PLASTIC
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Wax: Waxes are a diverse class of organic compounds that are hydrophobic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to give low viscosity liquids. Waxes are organic compounds that characteristically consist of long alkyl chains. They may also include various functional groups such as fatty acids, primary and secondary long chain alcohols, unsaturated bonds, aromatics, amides, ketones, and aldehydes.
WAX
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CO N CR ETE
A N D
WA X
Concrete: Concrete is a composite material composed of coarse aggregate bonded together with a fluid cement that hardens over time. Most concretes used are lime-based concretes such as Portland cement concrete or concretes made with other hydraulic cements, such as ciment fondu. However, asphalt concrete, which is frequently used for road surfaces, is also a type of concrete, where the cement material is bitumen, and polymer concretes are sometimes used where the cementing material is a polymer.
CO N CR ETE
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E A R LY
E X P ER I M E N T S
PRIMARY PHASE In the primary phase, many types of materials have been researched and experimented as it shows below.
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23HZ
3 3 H Z
43HZ
53HZ
6 3 H Z
73HZ
83H Z
9 3 H Z
103HZ
FREQUENCY PATTERN A range of frequency for sound have been applied for the foam shaping process. A speaker is put at the bottom of foam liquid.
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ABSOPTION AND REFLECTION A sound meter is put at the bottom of the device for the decibel recording, and the material sample are in the middle of it. The transparent acrylic is easier for observation. A small window of the box is for real-time taking notes.
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SOUND TESTER
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SHAPE GENERATING Three kinds of materials are applied in the final shaping phase: expanding foam, wax and concrete,
VAC U U M
1mi n
3 m in
5mi n
7 m in
9mi n
1 0 m in
G E N E R AT IN G
PROCESS
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C O N C R E T E
WAX
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M E A S U R I N G
D E V I C E
After measurements for decibel reduction for 16 samples from 4 materials and 4 basic shapes were made, these results were used to build graphs and topographical representations to compare with each other.
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PLA Plastic
PU Foam
Concrete
Wax
M E A S U R I N G
O U T P U T S
After measurements for decibel reduction for 16 samples from 4 materials and 4 basic shapes were made, these results were used to build graphs and topographical representations to compare with each other.
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Hz
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Hz
Hz
1C 2C
1B 2B
1A 2A
1 2
3C 4C
3B 3A
4B 4A
3 4
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DIG I TA L
S I M U LAT I ON S
SHAPES There are totally 16 kinds of shapes are generated in the previous experiments, and they are made of four types of materials.
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THE SPLASH A sound field is put at the bottom of the liquid, and screens are captured according to time line. The effects of sound to the liquid could be easily observed in these simulations.
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MIXING MATERIALS Tow types of material are mixed with the sound effects in this experiment. One of the material is low density and drops slow, in reverse, another has higher density.
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M I X E D
M AT E R I A L
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SI DE
V I E W
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TO P
VIEW
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ROLL I NG
SUR FAC E
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E X PL O SI ON
P O IN T S
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Two types of materials are mixed while exploding together, and the moments are captured while doing the simulations.
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INTERACTIONS BETWEEN MATERIALS
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4 SO NIC [ A
CRYS TAL
M ETA M ATER I A L
ARRAY S
AP PROAC H
TO
SOUN D]
In the year 2000 the research of Liu et al. paved the way to acoustic metamaterials through sonic crystals. The latter exhibit spectral gaps two orders of magnitude smaller than the wavelength of sound. The spectral gaps prevent the transmission of waves at prescribed frequencies. The frequency can be tuned to desired parameters by varying the size and geometry of the metamaterial.
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A PPR OAC H The main approach of the design process was to comfront with the question of which sounds do we want to preserve, encourage, multiple. The main objective was always keep the attitute of “adding nothing to the existing soundscape, but rather offering new ways of listening to what is already there.”. With the support of these, our ideas shaped around the “creation of positive soundscapes”, where the design used as a tool to filter urban layers of soundscape to utilise resonance and act as a catalyst between sonic landscapes and public areas.
METAMATERIALS A metamaterial is a material engineered to have a property that is not found in nature. They are made from assemblies of multiple elements fashioned from composite materials such as metals or plastics. The materials are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. (Soundwaves in our case. Metamaterials derive their properties not from the properties of the base materials, but from their newly designed structures.
SONIC CRYSTAL ARRAY The pioneering experimental work on the sound attenuation by periodic structure - in the form of an outdoor modern art sculpture - was made in 1995. The minimalistic sculpture by Eusebio Sempere, exhibited at the Juan March Foundation, Madrid, consists of a periodic square symmetry arrangement of hollow stainless steel cylinder with a diameter of 0.029 m and a lattice constant (distance between 2 cylinders next to each other) of 0.10 m was used in their experiment. In such case of the acoustic audible sound, these periodic distributions of cylinders (also called scatterers) are known as Sonic Crystal (SC). The cylinders were fixed on a circular platform which can be rotated around the vertical axis.
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O R C H E S T R AT E D
C I T Y
S O U N D M A R K S R E C Y C L I N G
S O U N D
F I LT E R I N G
D E V I C E
S O N I C
C A T A L Y S T
“Noises are sound we learn to ignore.”
M. Schaffer The main approach of the design process was to comfront with the question of which sounds do we want to preserve, encourage, multiple. The main objective was always keep the attitute of “adding nothing to the existing soundscape, but rather offering new ways of listening to what is already there.”. With the support of these, our ideas shaped around the “creation of positive soundscapes”, where the design used as a tool to filter urban layers of soundscape to utilise resonance and act as a catalyst between sonic landscapes and public areas.
M E T A M A T E R I A L S When it comes to achive beyond the borders of conventional sound control approaches, the field of metamaterials revealed a method that is highly convenient to implement to our ideas. This method was called “Sonic Crystal Array”. But before explaining more about it, first we have to reveal more about the metamaterials itself. A metamaterial is a material engineered to have a property that is not found in nature. They are made from assemblies of multiple elements fashioned from composite materials such as metals or plastics. The materials are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. (Soundwaves in our case. Metamaterials derive their properties not from the properties of the base materials, but from their newly designed structures. Their precise shape, geometry, size, orientation and arrangement gives them their smart properties capable of manipulating electromagnetic waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials.Appropriately designed metamaterials can affect waves of electromagnetic radiation or sound in a manner not observed in bulk materials.
S O U N D F I LT E R I N G Metamaterials textured with nanoscale wrinkles could control sound or light signals, such as changing a material’s color or improving ultrasound resolution. Uses include nondestructive material testing, medical diagnostics and sound suppression. The materials can be made through a high-precision, multi-layer deposition process. The thickness of each layer can be controlled within a fraction of a wavelength. The material is then compressed, creating precise wrinkles whose spacing can cause scattering of selected frequencies., sonic waves can exhibit negative refraction.
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ACOUSTIC MATEMATERIALS
two-centimeter slab absorbed sound that normally would
Acoustic metamaterials control, direct and manipulate
require a much thicker material, at 400 Hz. A drop in
sound in the form of sonic, infrasonic or ultrasonic waves
amplitude was observed at 400 and 1100 Hz.[10][20]
in gases, liquids and solids. As with electromagnetic waves,
The amplitudes of the sound waves entering the surface
sonic waves can exhibit negative refraction.
were compared with the sound waves at the center of the metamaterial structure. The oscillations of the coated
Control of sound waves is mostly accomplished through the
spheres absorbed sonic energy, which created the frequency
bulk modulus, mass density and chirality. The bulk modulus
gap; the sound energy is absorbed exponentially as the
and density are analogs of permittivity and permeability
thickness of the material is increased. The key result
in electromagnetic metamaterials. Related to this is the
here is a negative elastic constant created from resonant
mechanics of sound wave propagation in a lattice structure.
frequencies of the material. Its projected applications, with
Also materials have mass and intrinsic degrees of stiffness.
a future expanded frequency range in elastic wave systems,
Together, these form a resonant system and the mechanical
are seismic wave reflection and ultrasonics.
(sonic) resonance may be excited by appropriate sonic frequencies (for example audible pulses).
P H O N O N I C
C R Y S T A L S
Research employing acoustic metamaterials began in the
Phononic crystals are synthetic materials that are formed by
year 2000 with the fabrication and demonstration of sonic
periodic variation of the acoustic properties of the material
crystals in a liquid. This was followed by transposing the
(i.e., elasticity and mass). One of the main properties of the
behavior of the split-ring resonator to research in acoustic
phononic crystals is the possibility of having a phononic
metamaterials.
bandgap. A phononic crystal with phononic bandgap prevents phonons of selected ranges of frequencies from being
The earlier studies of acoustics in technology, which is called
transmitted through the material.
acoustical engineering, are typically concerned with how to reduce unwanted sounds, noise control, how to make
To obtain the frequency band structure of a phononic crystal,
useful sounds for the medical diagnosis, sonar, and sound
Bloch theory is applied on a single unit cell in the reciprocal
reproduction and how to measure some other physical
lattice space (Brillouin zone). Several numerical methods
properties using sound.
are available for this problem, e.g., the planewave expansion method, the finite element method, and the finite difference
Using acoustic metamaterials the directions of sound
method. A brief survey of numerical methods for calculating
through the medium can be controlled by manipulating
the frequency band structure is provided by Hussein (2009).
the refractive index. Therefore, the traditional acoustic technologies are extended and may eventually cloak certain
The basis of phononic crystals dates back to Isaac Newton
objects from acoustic detection.
who imagined that sound waves propagated through air in the same way that an elastic wave would propagate along a
Since the acoustic metamaterials are one of the branch
lattice of point masses connected by springs with an elastic
of the metamaterials, the basic principle of the acoustic
force constant E. This force constant is identical to the
metamaterials is similar to the principle of metamaterials.
modulus of the material. Of course with phononic crystals of
These metamaterials usually gain their properties from
materials with differing modulus the calculations are a little
structure rather than composition, using the inclusion
more complicated than this simple model.
of small inhomogeneities to enact effective macroscopic behavior. Similar to metamaterials research, investigating
Based on Newton’s observation we can conclude that a
materials with Negative index metamaterials, the negative
key factor for acoustic band-gap engineering is impedance
index acoustic metamaterials became the primary research.
mismatch between periodic elements comprising the crystal and the surrounding medium. When an advancing wave-front
S O N I C
C R Y S T A L S
1D
meets a material with very high impedance it will tend to increase its phase velocity through that medium.
In the year 2000 the research of Liu et al. paved the way to acoustic metamaterials through sonic crystals. The latter
Likewise, when the advancing wave-front meets a low
exhibit spectral gaps two orders of magnitude smaller
impedance medium it will slow down. We can exploit this
than the wavelength of sound. The spectral gaps prevent
concept with periodic (and handcrafted) arrangements of
the transmission of waves at prescribed frequencies. The
impedance mismatched elements to affect acoustic waves in
frequency can be tuned to desired parameters by varying the
the crystal – essentially band-gap engineering.
2D
size and geometry of the metamaterial. The position of the band-gap in frequency space for a The fabricated material consisted of a high-density solid lead
phononic crystal is controlled by the size and arrangement of
ball as the core, one centimeter in size, which was coated
the elements comprising the crystal. The width of the band
with a 2.5-mm layer of rubber silicone. These were arranged
gap is generally related to the difference in the speed of
in a crystal lattice structure of an 8 × 8 × 8 cube. The balls
sound (due to impedance differences) through the materials
were cemented into the cubic structure with an epoxy.
that comprise the composite.
3D
Transmission was measured as a function of frequency from 250 to 1600 Hz for effectively a four-layer sonic crystal. A
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S O N I C
C R Y S T A L
A R R A Y
It is known that infinite periodic structures do not support wave propagation in certain frequency ranges known as Bandgaps relating to the spacing between the scattering elements (Lattice constant).The ability to manipulate have produced a number of practical application such as manipulating the group velocity of light, superlensing effect, designing highly efficient nanoscale lasers, sharp bend radius waveguides, microwave cloaking devices, optical computer chips and enhancing surface mounted microwave antennas. The pioneering experimental work on the sound attenuation by periodic structure - in the form of an outdoor modern art sculpture - was made in 1995. The minimalistic sculpture by Eusebio Sempere, exhibited at the Juan March Foundation, Madrid, consists of a periodic square symmetry arrangement
ORGAN OF CORTI, FRANCIS CROW, DAVID PRIOR
the propagation properties of electromagnetic radiation
of hollow stainless steel cylinder with a diameter of 0.029 m and a lattice constant (distance between 2 cylinders next to each other) of 0.10 m was used in their experiment. In such case of the acoustic audible sound, these periodic distributions of cylinders (also called scatterers) are known as Sonic Crystal (SC). The cylinders were fixed on a axis. Sound attenuation was measured at various angles in outdoor conditions for sound-wave vectors perpendicular to the cylinders’ vertical axes. Having a small filling fraction of 0.066 the experiment results showed several maxima (sound attenuation) and minima (sound reinforcement) in the frequency spectrum. The first (lowest) gap in the band structure which has a centre frequency at 1.7 kHz could be attributed to the geometry of the structure as shown in figure 1.4. Ever since this publication, research on the application of
LA VERDAD, EUSEBIO SEMPERE
circular platform which can be rotated around the vertical
periodic arrays of cylinders for noise control has increased.
physical properties such as density and speed of sound between the scatterer and the matrix material. Sonic crystals seem therefore very attractive as acoustic passband filters. The nature of the host materials can be used to differentiate between sonic and phononic crystals. If the host material (matrix material) is solid then the term ‘Phononic Crystal’ is used for the artificial crystal. In a phononic crystal, both longitudinal and transverse shear waves (elastic waves) may exist and couple with one another which will add to the complexity of the nature of eigenmodes. In contrast, sonic crystals are considered to be independent of the transverse waves. The scatterers are typically made of solid materials and the host matrix is air/fluid to give high acoustic
ORGAN OF CORTI, FRANCIS CROW, DAVID PRIOR
Such bandgap phenomena require a large contrast in
impedance contrast between them.
that there are only one unique 1D periodic system, five 2D and fourteen 3D different lattices. The majority of this work considers the sonic crystal as 2D arrangement, for which the five distinct Bravais lattices with their principle lattice vectors and angles. It can be said that the crystal structure is invariant under translations and, sometimes, under rotations. The crystal structures are classified into three categories, that is, one-dimension (1D), two-dimensions (2D), and threedimensions(3D) crystal by means of the group theory. A primitive cell is a minimum cell corresponding to a single lattice point of a structure with translational symmetry in
ORGAN OF CORTI, FRANCIS CROW, DAVID PRIOR
By means of the use of group theory, it has been proved
the given dimensions. A lattice can be characterized by the geometry of its primitive cell.
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P H O N O N I C
C R Y S T A L S
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D I G I T A L
S I M U L A T I O N S
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S O N I C
C R Y S T A L
D E V I C E
As part of testing and simulating the sonic crystal array phenomenon, we build a device to stimulate a scaled experiment of an actual sonic array. A sound source, a recorder and 60 transparent acryllic tubes were used for the device. The tubes sit on a grid of circles which has the option to remodify the arrangement of the array in terms of being narrow or wider. The aim of the device and the test is to physically and digitally see how a certain level of frequency range changes with this spesific sonic array. 4 sample sound types were used as part of the experiment. 1st sample is 16 different frequencies played one by one and recorded with and without the array inbetween the sound source and the recorder. And the other 3 records were “a loud group of people”, “traffic jam”, “train passes”. Each recording played with and without the array inbetween and compared digitally through the spectrogram of the recordings.
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00 B A S E
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4500 Hz 4000 Hz
00 S U P E R P O S I T I O N
F R E Q U E N C Y
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R A N G E
01 B A S E
01 [ w i t h ] A R R A Y
4500 Hz 4000 Hz
01 S U P E R P O S I T I O N
A
G R O U P
O F
P E O P L E
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02 B A S E
02 [ w i t h ] A R R A Y
4500 Hz 4000 Hz
02 S U P E R P O S I T I O N
T R A F F I C
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J A M
03 B A S E
03 [ w i t h ] A R R A Y
4500 Hz 4000 Hz
03 S U P E R P O S I T I O N
T R A I N
A P P R O A C H E S
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5 INIT IAL PROPOS AL S F OR
AN
U RBAN
INT E RFAC E In the light of sound studies and material studies that was taken throught, we understood sound cannot be considered with a singular aspect. It is multilayered and multiformed. And to handle that amount of data and scale difference, we find it right to perceive Queen Elizabeth Park as multi scales. There fore, our approaches of creating urban interfaces in multiple scales occured. Each scale level is handling a different aspect of the soundscape we may perceive in those specific areas. But each approach is not for single location. The possibilities are almost infinite. Throughtout the following pages, you will find 3 proposals for 3 shifting scale levels. Each proposal is a representative of its own group of possibilities.
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1D Scale Point
2D Scale Surface
3(+)D Scale
Infinite Loop
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F L UID
C RYSTA L
A R R AY
PROPOSAL TYPE: 1D (POINT) The first of 3 proposals is the “Point� base approach. This proposal relies on the railways overpasses and underpasses around the city of London. The experimental approach was actualized in the peripheries of the Queen Elizabeth Olympic Park as one of the options/posibilities.
CRYSTAL ARRAY AS A MOLD The idea approaches the crystal array phenomenon from a different angle and using the array idea to form a mold consist of holes on its surface. This mold later used in digital fluid simulations to shape a more experimental crystal array structure.
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S E L E C T E D
P O I N T S
The logic behind the idea of site selection for the fluid crystal array is to focus not inside the Queen Elizabeth Olympic Park, but to the neighbouring areas around the Park, such as Hackney Wick, Tottenham Hale and St. James Street.
Tottenham Hale
Hackney Wick
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T O T T E N H A M
H A L E
H A C K N E Y
W I C K
Average dB
Average dB
Minimum dB
Minimum dB
Maximum dB
Maximum dB
Average Frequency
Average Frequency
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9 5 2
O V E R P A S S E S
London’s cityscape has a characteristic of being multilayerd and besides many visible and bold features of the city, being multilayered is an almost unrecognizable but unique feature of the capital. This feature therefore creates its own infrustructural objects.
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H A L E T O T T E N H A M
W I C K H A C K N E Y L O N D O N A R O U N D O V E R P A S S E S O T H E R V A R I O U S
9 5 2
O V E R P A S S E S
In our case, this infrustructural elements are railway overpasses where the public space meets with a transportation lane. This intersection is not only a visible one, but also a hearable one. The site selection of the first proposal based its roots to these railway overpasses scattered around the city of London.
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T O T T E N H A M
H A L E
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H A C K N E Y
W I C K
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C R Y S T A L
A R R A Y
M O L D
The idea approaches the crystal array phenomenon from a different angle and using the array idea to form a mold consist of holes on its surface. This mold later used in digital fluid simulations to shape a more experimental crystal array structure.
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C R Y S T A L
A R R A Y
M O L D
The first of 3 proposals is the “Point� base approach. This proposal relies on the railways overpasses and underpasses around the city of London. The experimental approach was actualized in the peripheries of the Queen Elizabeth Olympic Park as one of the options/posibilities.
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S O U N D
S T R U C T U R E
PROPOSAL TYPE: 2D (SURFACE) One of the main property about sound is that it is flexible and always changing in real time. In the Elizabeth Olympic Park, the soundscape is complicated and you can have totally opposite sound experience when walking through the park. In order to design based on the different situation in different places and design for the different sound requirements in every specific sites. The flexibility of sound need to be taken as a design input to make the design result more adaptive to the sound environment.
STRUCTURE A strcture for the facade of architecture or public spaces is made and covered with surfaces which can be the skin of the structure. Experiments with the crystal array idea are done to find the best shape for the structure and skin surface. As a result, A design proposal is developed which can act as a filter to transfer nagative noise into positive range of sound, thus creating a better sound environment or inhabitance for citizens.
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C R AYSTA L
A R R AY
DIfferent shapes are used as components to arrange
The pattern of arranging the crystal array components is kept
cystal array both in horizontal and vertical direction. Digital
the same. Different shapes of components including triangle,
simulation showing sound particles propagating through the cystal array, which is used to find the best shape of component for arranging a crystal array.
quadrangle, pentagon and hexagon are tested with the same sound souce. After simulation, the result showed that hexagon hase the best performance with sound when it is arranged to be a crystal array.
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Triangle
Quadrangle
Pentagon
Hexagon
GEOMETRICAL DEVELOPMENT VORONOI a Voronoi diagram is a partitioning of a plane into regions based on distance to points in a specific subset of the plane. That set of points (called seeds, sites, or generators) is specified beforehand, and for each seed there is a corresponding region consisting of all points closer to that seed than to any other. These regions are called Voronoi cells. The diagram showing the process of making the sound structure. At first a 2d voronoi diagram is used and made into a 3d voronoi cuboid, then components from this 3d voronoi start to be taken off. The edges of the left components are extracted to create connected pipes. The intersection areas of those pipes are smoothed and the result showing the basic structure in the end.
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FACAD E
PERFORMANCE
Digital simulation showing how sound particles propagating through the sound structure created. Single facade of the structure is taken into the simulation first, the result showing it has the similar function of a crystal array, acting like a filter reducing the amount of particles passing through the facade. And when one more facade is added behind the first one, the affection becomes stronger. Then the 3d sound structure created from the 3d voronoi is tested as well. The result showing the sound performance is quite good, the density of sond particles is different in different layers of the structure, a huge amount of sound particles is blocked when going through the structure.
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SUR FAC E
S K I N
The diagram showing the process of creating the surface skin for the sound structure. The crystal array idea is taken into consideration again, the surface skin is designed with random circular holes acting as gaps between components of a crystal array. The surface skin is used to cover the structure and combine it together to create better sound performance.
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DEVELOPMENT Four steps are used to create the sound structure based on the soundscape of each specific place. One site model is made to be the example of creating a customized sound structure.
1. The site model is taken into sound simulation, sound souce is placed based on the real sound environment around this building. And the position of sound particles around the building is got from the simulation.
2. Based on the process of creating the sound structure, the sound particles around the building are used as the points for making a 3d voronoi. Then edges are extracted from the 3d voronoi to form the line of a initial structure.
3. The lines are extruded to create the body of shape, the intersection areas of each line are smoothed to make it a little bit biger and natural connected.
4. Surface skin is put onto the structure to cover it and make the space inside the sound structure more clear, which might act as different sound experience layers or inhabitance areas later on.
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OPE N
S PAC E
The model showing an example of how the sound structure can be used in a public open space. The site is a walking street between two rows of buildings. The same logic is followed to create the sound structure. And it automatically forming a semi-opened public activity area, which can not only improve the sound environment in the street and buildings, but also activate this street to be a relaxing place for people.
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The sounscape of the street is detected by digital simulation. Sound particles inside the street are gotten form the simulation.
The same process is followed to create the sound structure for the street.
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MOV ING
PA NE L S
Sound is changing all the time, and it will be necessary to design something adaptive to the flexibility of sound environment, which means it should have the ability to update itself due to the changing sound in real time. A facade with moving panels is created for the places with various soundscape, which can adapt to the complex sound environment and give a new approach to take sound as a force to develop different design.
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EXAMPLE TITLE Contrary to popular belief, v Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of “de Finibus Bonorum et Malorum� (The Extremes of Good and Evil) by
DEVELOPMENT Sound Particles
Surface Construction Control Lines
Surfaces
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SOUND PANELS Digital sound simulation is firtly done to find out how this architecture is affected by sound at normal time. Sound particles around the architecture are gotten from the simulation. If the density of the sound particles is high, it means this area of the architecture is strongly affected by the sound, so the panels here should be thinner and stretch out more from the surface of the architecture in order to reduce the noise; vice versa. Following this logic, a waving surface can be created
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MOVING PANELS
panels without sound effect
facade without sound effect
facade with sound effect
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panels with sound effect
This building is located in a residential place near a railway
Digital simulation is run to understand the situation when a
overpass. So if a train is passing by the building, it will
tarin passing by, how the sound particles will hit the building
release a huge amount of noise which will affect the living
and vecter of the sound particles is taken as the perpendicular
environment in the residential area.
line of panels to control them moving towards the right direction.
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MO DUL A R
C RYSTA L
A R RAY
PROPOSAL TYPE: 3D (INFINITY LOOP) The third proposal’s main idea is to shape a basic 3d sonic crystal array with multiple deformation procedures. These deformations and distortions might occur according to the soundscapes of the environment that the array is placed in.
MODULARITY This last proposal was based on the idea of a infinite loop of modules. Each module can form its shape according to the soundscape of the environment. The height can be various. It might be on the ground level dealing with more daily urban soundscapes, or the modules can lift up to 1 km long and reach to a soundscape consist of aircraft noises. As part of the third proposal, the site selection approach was quite different than other 2 proposals. Because the dimensions of the modular array is infinite, two edges in terms of soundscape were selected. A natural habitat of Hackney Marshes and a construction site inside Pudding Mill Lane.
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T W O
S H AR P
ED GE S
As part of the third proposal, the site selection approach was quite different than other 2 proposals. Because the dimensions of the modular array is infinite, two edges in terms of soundscape were selected. A natural habitat of Hackney Marshes and a construction site inside Pudding Mill Lane.
Hackney Marshes (Natural Habitat)
Pudding Mill Lane (Construction Site)
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P U D D I N G
M I L L
L A N E
H A C K N E Y
M A R S H E S
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Average dB
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