HF Jan12 HF

Reviewed ProAc Response D Two British to their bones‌ B.M.C. C1 Integrated A very unusual amplifier!

VAF MPB SW4 Sub A bargain in black?

TDK LOR NC-150 Low-cost noise-cancelling headphones...

Vivid Audio B1 CES SHOW REPORT y EveAnna Manle k! oo launches Chin

Mar/Apr 2012 $7.95

Extraordinary detail and resolution!

on test

B&W 802 DIAMOND LoudSPEAKERS

F

ew loudspeaker companies around the world have reached the level of commercial success that Bowers & Wilkins has enjoyed over the last decade or so. Connected to such accomplishment is a research and development pool of profound depth allowing the company to develop a number of advancements that have put it technologically ahead of most of the competition. In terms of the ratio between engineering versus value for money, in the last few years, B&W has been hard to beat.

And nothing illustrates this principle better than the top products’ inclusion of the B&W-developed diamond tweeter which now applies throughout the series.

For someone who appreciates aesthetic design, the arresting style of the 802’s cabinet work would be the place to start a

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description. Up top, in a machined wedge within the gloss black midrange ‘egg’ sits the diamond tweeter in its own fluteshaped enclosure. The midrange pod itself lies—in a soft leather surround—atop a Matrix-reinforced curved cabinet of 35mm ply which is shaped by a proprietary method at B&W’s own factory in the United Kingdom.

Our review pair came in a nice furnituregrade cherry veneer that seamlessly wraps around the curved enclosure. Alternatives are real wood veneer in rosenut: also available is a gorgeous piano black gloss finish.

Diamonds Are Forever The 25mm diamond tweeter belongs to the Nautilus family of high frequency transducers and features a number of refinements that improve on previous generations.

B&W claims diamond possesses properties that make it close to ideal as a material for tweeter domes; it’s extremely stiff while being very light. The tweeter is driven by not one, but four powerful neodymiumiron-boron magnets designed for maximum flux concentration, while the overall design has been engineered to provide maximum output and wide dynamic range at very low distortion. The long Nautilus tube is a simple and clever mechanical means of drawing the tweeter’s back wave away from the dome’s rear surface and out the back of the tapering tube. Being housed in its own decoupled pod, which sits in a compliant compound, actually allows a far better dispersion pattern that is unaffected by the front baffle and isolates the tweeter from enclosure vibrations.

On TEST

The tweeter is driven by not one, but four powerful neodymium-iron-boron magnets for maximum flux

The elongated and organic midrange ‘egg pod’ is constructed from ‘Marlan’, a hard material with suitable resonant properties for the 152mm diameter yellow Kevlar FST driver (now a B&W trademark driver) and is beautifully finished in gloss black.

FST stands for ‘Fixed Suspension Transducer’ and is a unique method of attaching the cone to a foam/polymer instead of the traditional rubber or foam surround. Benefits are claimed in terms of midrange transient response and cone resonance control. An aluminium phase plug protrudes from the

centre of the driver. The main enclosure houses twin 203mm Rohacell drivers of very high spec.

Twin magnet systems reduce distortion and improve cone control while enhancing dynamics and allowing higher playback levels. The bass drivers are aided by B&W’s dimpled ‘Flowport’ bass reflex system, whose port exits at the bottom of the enclosure which itself stands on an elevated plinth.

The crossovers use very high quality parts, including Mundorf capacitors and a host of other quality components that B&W says were chosen only after extensive listening tests. The speaker features custom highquality binding posts suitable for bi-wiring.

Included with each speaker is an adjustable spiking system that is amongst the best I have seen on any loudspeaker system.

Not only are the massive spikes extremely well-machined, but they’re easily adjustable and look a million bucks. In the box, the 802 Diamond comes with removable steel roller-balls however, the sheer weight of the speakers can still cause damage to wooden floors (roller-ball tracks) when wheeled around. To my mind, rubber wheels would have been a superior solution.

The 802 Diamond’s frequency range is quoted as 27Hz to 33kHz (–6dB) with the frequency response quoted as 34Hz to 28kHz at ±3dB. Nominal impedance is 8Ω with a minimum of 3.5Ω. Efficiency is stated at 90dBSPL for a 2.83V input at one metre.

On paper that may be valve-friendly—indeed I achieved superb, and surprising, results with a 35-watt SET—but I found that full dynamic expression was better served with a high-powered solid-state amplifier.

Crossover points are quoted as 350Hz and 4kHz which illustrates the FST midrange driver’s wide bandwidth capabilities.

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FEATURE

KR Audio: A Factory Tour Editor Borrowman makes it sound terribly simple to visit KR Audio’s factory.

He knows I’m going to Italy; he knows I’m fond of valve amplifiers, so he makes it sound easy… and exciting. ‘KR is the only valve amplifier company in the world that makes its own valves: they even blow their own glass,’ he says. ‘They make the biggest valves used in hi-fi equipment, and also the only ones created specifically for hi-fi…and Prague is only just down the road a bit from Italy.’ Of course I’m hooked.

T

he taxi arrives at my hotel 40 minutes late which for Prague, I’m told, is pretty good. The driver is surly, annoyed because I’m taking him far away from the tourist zones where there are lots of foreigners to rip off and he lets me know it in no uncertain terms. We move steadily to the north-east and the beautiful, strikingly-detailed architecture of the old city gives way to the brutality of Soviet-era pragmatism. There are large tracts of vacant land overgrown with weeds, lots of places to buy beer. Eventually, after some backtracking and a bit of dumb luck he finds the street. The building wearing

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the number I have been given is just where the bitumen gives way to a muddy track.

It’s a solid concrete structure and the security booth and boom gate out front are intimidating. The two women in there, who don’t speak a word of English, only get my drift when I write ‘KR’ on a piece of paper. They direct me in sign language through the arch and to the right, making a gesture for stairs. It’s the kind of wide, solid, bare concrete staircase that takes me back to the Cold War spy movies of the ‘60s. I go up one floor and look at the conglomeration of signs on the wall. No luck. I go up another flight. Nope. The third floor is

blocked off by a floor-to-ceiling iron railing, the gate chained and padlocked. There is a fourth floor but the staircase ends at a locked door up there. In four floors I haven’t seen or heard a sign of life.

I retrace and find the ‘KR’ that I missed first time around among the hodgepodge of signs on the first floor. I don’t know whether to turn right or left—there are no hints here—so I opt for right and go down a long, ominously dim hallway with doors on either side, all closed and locked, some wearing signs in Czech, some not. I come to a door that is slightly ajar.

It has ‘KR’ on it. I tap a bit timidly and open

Facing Page: KR Audio’s listening room with a Kronzilla at the bottom of the rack Left: Valve testing equipment: if the valve’s OK, the lights go on!

Below Left: The oldest component in the factory, the grid maker is used for electrical windings and is still in day-to-day use.

Below: A signed photograph of Marconi, one of KR Audio’s most treasured possessions

it wider. A middle-aged woman in black looks up from a brightly sunlit desk. ‘Are you Rod?’ she asks in a broad New York accent. ‘Would you like coffee?’ My relief is exceeded only by my sense of achievement.

An American in Prague Eunice Kron is an American of Hungarian extraction who met her husband in northern Italy and settled there for 26 years. He’s the one who got her into making valve amplifiers in the Czech Republic. She is one of the few women executives she knows of in the hi-fi industry and the only one running a factory, much less a factory making vacuum tubes. As we talk and the morning turns into afternoon it slowly occurs to me that this environment is exactly perfect for a company specialising in valves. There is equipment in here that

was made before the employees using it were born, and it’s used every day … such as the test benches consisting of rows of light bulbs that only illuminate when the valve plugged into the board is fully functional. Or the beautiful old gridmaker that for anyone with a technical bent is simply a joy to examine.

Valve manufacture by hand is an old, labour-intensive art requiring great skill and a lot of patience. It’s about as labour intensive as you can get. It has no logical place in the 21st century and yet here it is. I’m in a time warp. Everything in here is made by hand and the workers get all the time they need to get it right. KR must have a computer somewhere because I set up this meeting by email, but I don’t see it anywhere.

The company makes a range of 17 valve amplifiers of varying sizes and powers starting

with the entry level VA900 integrated amp.

But don’t be taken in by that ‘entry level’ moniker, this is not something you’ll find at JB HiFi, it’s an entry-level amplifier like the Ghost is an entry-level Rolls-Royce. And for all of those who lust after a KR and can’t afford any of the remarkable Kronzilla models.

There are seven Kronzillas ranging from a 35-watt per channel integrated amp to dual monoblocs of 100 watts. A few Kronzillas have been sold in Australia, the last one fetching $13,500. One remains unsold on our shores, the result of difficulties experienced by the local importer. ‘Serial number 458,’ Eunice tells me. I’m amazed.

‘I know where every Kronzilla is around the world,’ she says. And with amplifier production standing at around only 10 units a month—roughly three of them Kronzillas—I believe her. ‘We are small and so we remain flexible,’ she says, admitting also that it opens KR up to a range of vulnerabilities. ‘But I never intended to conquer the world,’ she adds.

Riccardo Kron’s Kronzilla I am prepared for my first look at a Kronzilla only because I read the original review in Australian Hi-Fi Magazine ‘way back in May 2006, but it still takes my breath away. It’s a 50-kilogram monster dominated by two 320mm high T-1610 valves that stand proudly erect at the front of the unit, the twin towers of hi-fi. It occurs to me that maybe KR makes its own valves because no other manufacturer would believe the brief.

avhub.com.au

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ON TEST

Marantz PM-KI-Pearl-Lite integrated AMPLIFIER

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Newport Test Labs

I

can almost hear the gasps of dismay when audiophiles take their first look at the Marantz PM-KI-Pearl-Lite. They’ll look at those tone controls on the front panel and say: ‘Tone controls? On an audiophile amplifier? Ken just has to be joking!’ And it isn’t just that Marantz has put bass and treble tone controls on the Pearl Lite… it’s that it’s also had the temerity to add a midrange tone control as well. I don’t think I’ve seen one of those since… mmm, well… not for a long time. (And for baffled readers who might be wondering about that reference to ‘Ken’, the Ken those audiophiles would be referring to is none other than Marantz’s own ‘brand ambassador’, Ken Ishiwata, who gets the final say on all products produced by Marantz, and even gets to ‘voice’ those Marantz products bearing his imprimatur—such as his Ken Ishiwata ‘Signature’ products—by selecting specific parts for use in the amplifier. Ishiwata also gets to ‘voice’ the models bearing his initials, so the ‘KI’ that’s part of this amplifier’s model number shows that this amplifier is one of the products that has benefited from his input.

So how is it that a ‘golden-ear’ signed off on an amplifier with bass, treble … and

Power Output: Single channel driven into 8-ohms, 4-ohms and 2-ohms noninductive loads at 20Hz, 1kHz and 20kHz. [Marantz KI-Pearl-Lite]

midrange… controls? You really don’t have to look any further than a single button elsewhere on the front panel: the ‘Source Direct’ button. Push this button and the tone controls disappear… at least they become invisible to the amplifier’s circuitry, so the amp essentially becomes a ‘purist’ audiophile amplifier at the push of a button.

But are tone controls really as bad as audiophiles suggest they are? Who was it who originally proclaimed: ‘Thou shalt not

use tone controls!’ and was gratified when the world listened? That’s two questions, and I have two answers. The first is that having tone controls is no bad thing: in some cases, being able to make minor tonal changes can be decidedly advantageous. You can use the bass tone control to add some bass to a speaker that’s a bit bass-shy—either by design or because you’ve put it in a position in your room in which it can’t deliver maximum bass—or you can take away some bass from a bass-heavy speaker, or one that has of necessity been positioned in a region of your listening room that results in an accentuated bass response. The treble control can be used to ‘tame’ a recording that has too much of it (many recording engineers have very poor high-frequency hearing, and compensate for it by adding treble when they master albums) or to increase treble response to compensate for a tweeter whose high-frequency response rolls off prematurely (and that’s a lot of them!). As for that midrange tone control… well, we’ll get to that later in this review.

The answer to the second question is a little more complicated. It’s true that many of the tone control circuits used thirty or forty years ago were ‘cut-price’ versions that

Marantz PM-KI-Pearl-Lite Integrated Amplifier

boosted some frequencies excessively, and were likely the major reason tone controls got a bad name. But that’s no longer the case and hasn’t been for about the past two decades.

Modern tone controls now use sophisticated circuits that boost (and cut) only those frequencies that require it, leaving all other frequencies untouched.

The Equipment

Newport Test Labs

The Marantz PM-KI-Pearl-Lite Integrated Amplifier (which I think I’ll hereafter refer to simply as the ‘Pearl Lite’ in order to save a few trees, not to mention the wear and tear on my computer keyboard) presents a solid, no-nonsense front fascia to the world. If we ignore the tone controls, there are really only seven controls on it. Of these, the power on/ on switch, the volume control and the input source selector (with positions for Phono, CD, Tuner, Aux/DVD, Recorder 1, Recorder 2) are absolutely essential. The others control speaker selection (two buttons that allow you to connect and use one or two pairs of speakers and operate them independently, or simultaneously—or, if you’re listening via headphones, not at all), channel balance

Power Output: Both channels driven into 8-ohms, 4-ohms and 2-ohms non-inductive loads at 20Hz, 1kHz and 20kHz. [Marantz KI-Pearl-Lite]

(a rotary control with a centre detent position), and internal signal routing: ‘Source Direct’ and ‘Power Amp Direct’.

The ‘Source Direct’ button removes all the tone control circuitry from the signal path, as well as the balance control, so the signal being input to the rear terminals goes straight to the volume control and thence (via the power amplifier circuitry) directly to the speaker terminals. The ‘Power Amp Direct’ button removes not only the tone controls, balance control and volume control, but even the source selection and pre-amplifier circuitry from the signal path. Essentially it turns the Pearl Lite from an integrated amplifier into a dedicated power amplifier, so if you use it in this mode you will have to provide your own external pre-amplifier.

Keen-eyed readers may have noticed a ‘Mute’ indicator just to the left of the volume control. Yes, there is a muting circuit, but it can only be operated using the remote control. However, this muting indicator also serves a second function, which is to indicate if the amplifier’s internal protection circuit has triggered. If this circuit does trigger for a reason that will resolve itself (such as excessive current draw caused by turning the volume too high when driving low-impedance speakers, for example), the Pearl Lite is clever enough to be able to reset itself after a few seconds. (Under similar conditions, some other amplifier protection circuits require the amplifier to be manually turned off at the mains power switch and then turned back on before they will reset. Interestingly, this is exactly what the User’s Manual says is supposed to happen. According to the Manual, the amplifier ‘enters standby mode’, but when I tested the circuit, it didn’t go into standby at all: it reset itself automatically.)

The rear of the amplifier is well laid-out, and the quality of all the fittings is much higher than you’d

ON TEST

MARANTZ PM-KIPEARL-LITE

INTEGRATED AMPLIFIER Brand: Marantz Model: PM-KI-Pearl-Lite Category: Integrated Amplifier RRP: $2,290 Warranty: Three Years Distributor: QualiFi Pty Ltd Address: Mt Waverley VIC 3149 1800 242 426 (03) 8542 1111 (03) 9543 3677 info@qualifi.com.au www.qualifi.com.au • Tone controls • Ability to defeat them • First class performance

• Mute only on remote • No pointer on volume control

LAB REPORT Readers interested in a full technical appraisal of the performance of the Marantz PM-KI-Pearl-Lite should continue on and read the LABORATORY REPORT published on the page 40.

Readers should note that the results mentioned in the report, tabulated in performance charts and/or displayed using graphs and/or photographs should be construed as applying only to the specific sample tested.

Lab Report on page 40 avhub.com.au

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ON TEST

PS Audio

PerfectWave Transport & DAC TRANSPORT & DAC

T

he PS Audio PerfectWave Disc Transport is not an ordinary disc transport… it’s an extraordinary disc transport! PS Audio’s PerfectWave DAC isn’t your ordinary DAC either, but it’s not quite as unusual as the transport.

But then I really wouldn’t expect much less from US outfit PS Audio. Founded by Paul McGowan and Stan Warren in 1973, they were high-end from the outset, and I bought two of their first products, a step-up transformer and a phono pre-amp. I still own the transformer, so there may be some bias in this review!

However, it should be noted that the PS Audio of today is not quite the PS Audio of yesteryear, because both founders ended up leaving the company. Warren was the first to leave, after which he formed Superphon.

McGowan followed fairly shortly after, to found Genesis Technologies with Arnie Nudell (ex Infinity). As often happens in such cases, without either of the founders at the helm, PS Audio ‘lost its way’ and after eight or ten years effectively stopped trading, at which point McGowan purchased the rights to the name and re-started the company on his own, taking over all design and man-

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agement. He’s since installed a CEO to run things, but is still very much hands-on in the design department.

PerfectWave Transport The PS Audio Perfect Wave transport (PWT) is out of the ordinary because it doesn’t decode the signal from the disc. Instead a two-stage process takes place, where the digital data on the disc is read, then stored in solid-state memory. After this, the data in the memory is decoded into a digital signal that can be decoded by a digital-to-analogue converter.

To get the signal off the disc in the first place, the PWT uses a DVD ROM drive. This is actually a really obvious thing to do because the PWT isn’t really ‘reading’ the data at all; it’s just ‘copying’ the data to memory.

This means that rather than depend on a disc’s own error-correction (at least in the case of a CD) it can use a multiple-read technique to ensure exact data retrieval. PS Audio says it’s developed its own version of this, which it calls MREC (Multiple Read Error Correction). While this system is superior, it’s not perfect. If enough data is missing from the disc (because of a scratch), no amount of multiple reading can fix it, and either some

error correction (interpolation) has to take place, or there will be a ‘tick’ or ‘gap’ in the recovered sound.

In addition to reading ordinary CDs, the PWT can also play back DVD ROMs containing WAV files at up to 24-bit/192kHz. So where would you get these? From one of the many websites now offering high-resolution music files for download, such as HD Tracks. Simply download the high-res file to your computer, convert it to a WAV file, burn it to DVD, then play the DVD in the PWT. (Remember to use the UDF 2.0 file system when doing this.) Despite being a DVD drive, the Perfect Wave Transport WILL NOT play DVD-A, nor will it play the SACD layer on hybrid SACDs. It will however, play back the CD layer of an SACD. Obviously, being a transport, the PWT has only digital outputs, provided by an AES/EBU XLR connector, a single gold-plated RCA socket, a standard Toslink optical link (24/96 max) or via PS Audio’s own proprietary I2S link (which uses standard HDMI socket). If you’re using a PS Audio DAC (as here) it’s best to use the I2S link to connect the two. PS Audio says that by doing so, you essentially ‘eliminate all jitter’. I was a little surprised

PS Audio PerfectWave Transport & DAC

not to find a digital output via a BNC connector… not that it’s that important, but simply because I prefer this connector type.

As you can see from the photograph, the review transport was fitted with an ‘expansion port’ which adds an RS-232 link, an infra-red link, and Ethernet capability. The SD card below the expansion port is used to store cover art and song title information as well as to program new firmware (about which more later).

PerfectWave DAC/Bridge The PerfectWave DAC (PWD) is available as a straight ‘DAC’ or, if you option in a ‘Bridge’ you will be able to connect the DAC to your home network, so that the PWD can play back music stored on your computer, NAS drive, or from the Internet. If you purchase a Bridge at the same time as the PWD, the cost is $800. If you purchase a Bridge later, it will cost you $899. (Don’t worry if you do purchase one later, because installation is easy. You just remove the plate on the rear, insert the Bridge and that’s it… except that if you want the Bridge to communicate wirelessly with your network, you’ll also need a PS Audio ‘Wireless Dongle’.)

In common with almost all high-end DACs, the PWD handles all the usual bitrates and word-lengths. You can also get it to upsample (or downsample) if you want, though my recommendation (and PS Audio’s) is to set the PWD to ‘Native’ whereby it will simply detect and use the original bit-rate and word-length of the digital data. In common with some DACs, PS Audio does allow you to choose what kind of filter you’d like to use. There are five choices. Filter 1 (MPAPOD) is a minimum phase apodising filter which features low pre-ringing, minimal group delay, minimised post ringing, good phase vs. frequency characteristics and a sharp filter cut-off. Filter 2 (MPSOFT) is a minimum

phase soft knee filter with low pre-ringing, minimal group delay, minimised post ringing, good phase vs. frequency characteristics and a softer filter cut-off. Filter 3 (LPAPOD) is a linear phase apodising filter with no group delay, perfect phase vs. frequency characteristics, minimal post ringing, some pre-ringing, and a sharp filter cut-off. Filter 4 (LPSOFT) is a linear phase soft knee filter with no group delay, perfect phase vs. frequency characteristics, minimal post ringing, some pre-ringing, and a softer filter cut-off. Filter 5 (MP1/2B) is a minimum phase recursive half-band symmetrical filter with minimised pre- and post-ringing, good group delay, good phase vs. frequency response, and a sharp cut-off.

I’m not going to go into detail about this because PSAudio does in its manual, which is available on-line, and spends more than two A4 pages explaining the differences. You can choose whatever one you most like the sound of. PS Audio doesn’t actually recommend one over the others, but does say that its favourite filter is Filter 1. We’ve included pics of how the filters affect square waves and impulses on page 33.

Before moving on to the listening sessions, I just have to mention the packaging system used by PS Audio, which is incredibly clever. Rather than simply using standard polystyrene ‘end’ extrusions, the components are instead supported on a ‘trampoline’ of polythene stretched across a cardboard frame.

This is very ‘green’ of PS Audio, but also means there’s minimal packaging to dispose of and that the components won’t be ‘jarred’ so much if the boxes are dropped during transport.

In Use & Listening Sessions I didn’t connect this Perfect Wave duo to the Internet (and so missed several software updates that occurred during the months I was

ON TEST

PS AUDIO

PerfectWave Transport & DAC Brand: PS Audio Model: PWT & PWD Category: Transport/DAC RRP: $3,499/$3,499* Warranty: Three Years Distributor: Magenta Audio Pty Ltd Address: 74 Mount Barker Road Stirling SA 5152 1300 785 205 (08) 8339 1000 (08) 8125 5850 sales@magentaaudio.com.au www.magentaaudio.com.au * Price without Bridge installed. With the Perfect Wave Bridge installed, the price is $4,299. (Bridge retails separately for $899.) See copy.

• Amazing interface • Expansion possibilities • Overall performance

• Display shifting • No SACD playback

LAB REPORT Readers interested in a full technical appraisal of the performance of the PS Audio PerfectWave Transport and PerfectWave DAC should continue on and read the LABORATORY REPORT published on the page 32. Readers should note that the results mentioned in the report, tabulated in performance charts and/or displayed using graphs and/or photographs should be construed as applying only to the specific sample tested.

Lab Report on page 32 avhub.com.au

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SOund TRavels

Sound Travels In each issue of Esoterica we feature an outstanding hi-fi system and interview its owner. In this issue, John Vandyke interviews Jeff Knox, who’s not only an audiophile of long standing, but also operates an appointment-only salon audio business—Jeff Knox Audio [www.knoxaudio.com.au]—from his own home in Woronora Heights, Sydney, NSW.

All Photographs: Melody Vandyke ©

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John Vandyke: How did your passion for music get started?

Jeff Knox: It all started for me in 1972 when I was 11 years old and I would spend time with an elderly neighbour of mine who had a very basic Sanyo 3-in-1 stereo and we would listen to Neil Diamond’s Hot August Night. I wanted my own stereo so badly; I couldn’t stop thinking about it.

JV: Was there a defining moment when you first realised that sound was an important part of the musical experience?

JK: I went to my first hi-fi show at Artarmon in Sydney with my father in the early 80’s. This is where I first experienced hi-end

SOund TRavels

audio equipment. At this show I learned that the quality of sound was so important in being able to re-create a musical event and the higher the resolution, the more realistic the music becomes.

JV: What kinds of music do you listen to mostly and who are some of your favourite artists/composers?

JK: I listen to a very wide range of music; however, I mostly listen to jazz and folk‌ although I have an increasing interest in classical music. Some of my favourite artists are Mary Black, Jennifer Warnes, Amanda McBroom, Steve Hackett, Nils Lofgren and Katie Melua.

The more resolving the system becomes, the deeper I am able to immerse myself in the music

JV: In what ways does music affect your life, and the way you feel?

JK: Listening to music is my main form of relaxation. It allows me to escape the pressures of life and transports me to a concert where I can lose myself. As I develop my system I find that the more resolving the system becomes, the deeper I am able to immerse myself in the music.

JV: What’s your most memorable hi-fi experience?

JK: In 1993 I was invited to go to a hi-fi show in Melbourne to help a friend who was demonstrating some equipment he imported to Australia. We stayed in the hotel where the show was being held and I met several manufacturers and audio designers and I was able to spend considerable

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SHOW REPORT

The UK National Audio Sh Northamptonshire, UK The UK’’s National Audio Show came at a time of considerable difficulty for the separates audio industry, a fact reflected by the absence of Absolute Sounds, the most successful distributor in the sector with brands such as Krell, Wilson Audio and Audio Research in its extensive portfolio.

Neither were there many major manufacturers in evidence… but they have gradually been moving over to the popular dealer shows in Bristol and Manchester for some time now.

What you would have found, if you hadn’t got lost in the maze of corridors in the over-sized Travelodge that is Whittlebury Hall, were lots of smaller manufacturers and distributors which mostly exhibited very interesting products and managed to make beguiling sounds with them. The building may not be pretty, but the rooms are better than your average venue and I encountered more than a few that proved difficult to tear myself away from.

T

he key trends at the NAS seemed to be both forward- and backwardlooking. In the progressive corner companies are clearly finding more accessible and better-sounding ways to play digital music files with

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dedicated source components and evermore USB DACs. At the same time, the ‘retro’ brigade continues to build even bigger and more efficient loudspeakers to go with the mother lode of lowpowered tube amplifiers that appears

seemingly every year. I heard several very impressive tube and horn systems at Whittlebury; there’s nothing quite like a genuinely high-efficiency speaker to bring out dynamics, and quality tube amps are the perfect partners.

ow Whittlebury, Anti-clockwise from Left: The team from Analogue Alchemy, out in force for the show; AstinTrew Concord Phono Stage; Stax SR-009 with Stax SRM-600t II Modified; Audio Alchemy’s headphone amp was designed by Alex Nitikin, who once designed for Creek, and uses an industrial FET.

small range of electronics in the entrylevel arena, competing with the likes of Arcam and Cyrus. This year it’s taking on the foothills of the high end with its Concord range, the first example of which is a heavily-featured phono stage with multiple inputs and adjustable gain, resistance and capacitance via controls on the front panel. It can run in stereo or mono and will cost £2,300.

Other components destined to join the range next year are a DAC with optional Firewire or USB input modules and a streamer/CD transport called a ‘DFE’ (digital front end).

Stax SR-009 Surfing the wave of the high-end headphone renaissance, Stax introduced a new range-topper dubbed SR-009 at NAS. This electrostatic ‘earspeaker’ has an ultra-thin diaphragm made from a ‘super-plastic’ that is much lighter than the plastic used in previous models. Stax says it has studied heat diffusion at the atomic level in order to improve the electrodes in this headphone and uses aluminium casework for maximum rigidity. The SR-009 sells for £3,695 and can be partnered with the SRM-600 Limited or SRM-007t II Modified energisers. [www.stax.co.jp] Some of the computer audio guys were also doing a fine job, one distributor putting together an entirely off-grid system to demonstrate the virtues of battery power with high-resolution components. The business may not

be buoyant, but this seems to have a positive impact when it comes to innovation and diversity from the industry.

Astin Trew Concord Astin Trew is a British company with a

Analogue Alchemy Analogue Alchemy is based in England but it’s run by Russians: one of whom— Alex Nikitin—once designed electronics for Creek. The company makes turntables that have more than a passing

avhub.com.au

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ON TEST

Velodyne Digital Drive DD-15+ Subwoofer

I

have never quite understood why people make subwoofers that bottom out midway between 30 and 40Hz… well, except, that is, for the obvious reason that it is all to do with price. It costs a lot of money to produce high levels of really deep bass cleanly. Which is most likely the reason why the Velodyne Digital Drive DD-15+ subwoofer’s recommended retail price comes in just shy of seven thousand dollars.

The Equipment What that sum of money buys you is a fairly large and very sturdy box, which is surprisingly stylish for a subwoofer, with a black piano gloss finish (a cherry version is also available, for no added cost) and an enclosure that gently curves from the front around to the rear. Fitted into the front of this is a 380mm driver (or, if you think it makes it seem bigger, a 15-inch driver). A full onethird of this subwoofer's total weight of 54kg is the mass of the driver's magnet alone.

The enclosure is sealed, so real power is required to make this driver move, given that

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has to compress the air enclosed inside the cabinet. Velodyne says that its Class-D ‘digital’ amplifier is good for 1250 watts 'RMS'… by which I take it that it means 'continuous'.

All this is controlled by Velodyne's digital signal processor, which is also used to optimise performance of the subwoofer for your room and sound system. To this end it comes with a proper measurement microphone, a stand, cables for the microphone, and also for a USB connection to a computer, computer software, a test tone disc, a composite video cable and a remote control.

The controls and features to which relatively ready access may be required are in a band across the front panel (underneath the removable grille, so they can be hidden away). These consist of a USB socket for connecting to a Windows computer for use with the optimising program, a mini-XLR socket for plugging in the supplied calibration microphone, a blue LED display (which can actually be seen though the grille, sensibly), the volume and low-pass crossover knobs, and an 'Auto EQ' button.

Also in this section is the small infra-red (IR) sensor for the remote control.

At the back of the subwoofer are inputs for speaker-level signals and both RCA and balanced XLR left and right inputs for linelevel signals. Both of these have two sets of matching inputs, one set carrying the original signal, the other carrying the signal after it has been run through a high-pass filter. That's useful for feeding powered satellite speakers.

This filter can be switched to either 80Hz or 100Hz. There are also IR, trigger, Ethernet, RS-232C and video connections. You can use some of these to daisy-chain multiple subwoofers together if your listening room happens to be the size of a football stadium.

Velodyne says that the subwoofer will plumb the depths to 9Hz, and easily hit 14.6Hz within its ±3dB range. Furthermore, Velodyne says that its 'typical' distortion level is less than one per cent, or half a percent, depending on the source. I gather that's not for the amplifier, but for the subwoofer itself!

The subwoofer is 460mm wide, 510mm high

Velodyne Digital Drive DD-15+ Subwoofer

and 570mm deep, which makes the overall enclosure large, but not overly so.

VELODYNE DIGITAL DRIVE DD-15+ SUBWOOFER

Listening Sessions All those connections and cables and the computer program were, I confess, somewhat daunting. But then I read up and found that the subwoofer has an easy set-up mode, called 'Auto EQ'. In fact the manual, which is by turns detailed and informative, and then infuriatingly uninformative, sets out four set-up modes.

There are the default settings which Velodyne says should give decent results in most rooms. Then there is something called 'SelfEQ'. With this setting you plug the test microphone into the front, put it where you're going to sit and have the subwoofer make its own test tone. This is allows the subwoofer to equalise (EQ) itself independently.

The mode Velodyne recommends you use is 'Auto EQ', while the most advanced mode is 'Manual EQ'.

With 'Auto-EQ' you run a test CD (supplied) through your system, so that the subwoofer adjustments are made taking the whole system into account, including your front stereo loudspeakers. Whereas the ‘Self-EQ’ mode only adjusts the levels on the parametric equaliser, the ‘Auto EQ’ mode sets the low-pass crossover frequency and slope and phase as well.

Manual EQ goes even further. You can set the centre frequencies of the equaliser and their 'Q' (the width of the effect on the frequency curve). You can set an infrasonic high pass filter if, for some reason, you don't want a large amount of really deep acoustic energy pouring into your room. You can fiddle with the settings for the presets as well. Plus more. These can be adjusted by plugging the subwoofer into your computer via the USB socket on the front, or by using the on-screen display generated by the subwoofer itself (hence the reason for the video outputs).

ON TEST

I stuck with the recommended Auto-EQ, after having first explored the Manual-EQ setup screens for a short while. I suspect most people will do it this way as well, because of the complexity of the whole thing, and the near-infinite number of combinations that you can play with in trying to further optimise the sound. The fact of the matter is that after running Auto-EQ, I thought that the whole thing sounded so very good that I felt no need to try to explore further.

I did at one point try to run 'Self-EQ' to see what, if any, difference that made. But here the manual frustrated me. I searched through the PDF file for 'Self' and found every reference, but nowhere did it say how you actually start it! Nor were there any real instructions on using the manual system via the TV. Believe me, it was far from intuitive. When I fired up the set-up process, the first thing it did was show me a frequency response screen with all the content wiped. I thought maybe this reset it, and so re-ran the Auto-EQ, only to find that it started with the settings it had previously made on the last Auto-EQ. As far as I could tell there was no obvious way (and by ‘obvious’, I mean printed in the manual) to return the subwoofer to its factory defaults.

On the other hand, the Auto-

Brand: Velodyne Model: DD-15+ Category: Subwoofer RRP: $6,999 Warranty: Two Years Distributor: Revolution Technologies Pty Ltd Address: 37 Eagleview Place Eagle Farm QLD 4009 (07) 3902 8051 (07) 3902 8050 sales@revolutiontechnologies.com.au www.revolutiontechnologies.com.au

• Superb bass extension • Superb volume levels • Full room/system EQ • Gaping holes in PDF manual • Software could be improved

LAB REPORT Readers interested in a full technical appraisal of the performance of the Velodyne DD15+ Subwoofer should continue on and read the LABORATORY REPORT published on page 26.

Readers should note that the results mentioned in the report, tabulated in performance charts and/or displayed using graphs and/or photographs should be construed as applying only to the specific sample tested.

Lab Report on page 26 avhub.com.au

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Interview

W

hilst preparing for a trip to the USA I stumbled upon an audio site that I didn’t know about and which was going into a great deal of detail about open baffle and point source speaker design: www.linkwitzlab.com. I had been researching open baffle speakers for my blog after recently reconnecting with Alain Wacquet, a friend who designed such speakers in the 1980s under the AW Audio brand. At the time I was building Microphase speakers in France, and he and I were often co-exhibitors at the Paris Hi-Fi Show. Wacquet’s designs were really ‘out there’ at the time—particularly his penultimate design (EA-16) released in 1987 and his last design, the Tranparence (1995).

The funny thing is that the name Linkwitz Lab should have been an instant hit, but it was only after an email exchange with the owner of the website that the penny finally dropped: I was indeed talking to Siegfried Linkwitz, whose name is immortalised in the loudspeaker field (the Linkwitz-Riley filter is an infinite impulse response filter used in Linkwitz–Riley audio crossover networks.

It’s also known as a Butterworth squared filter) and famous for teaching KEF engineers about group delay and transient response. The initial contact came about in the early 70s, when KEF’s engineers were shopping around to buy a state-of-the-art FFT analyser and ended up at Hewlett-Packard in California, where Linkwitz was working at the time with his colleague Russ Riley. You can read an amusing account of that story here: www.linkwitzlab.com/AX%20interview.htm. (You can also find an interview with Siegfried here: www.stereophile. com/interviews/503/) Interestingly enough, I let another penny drop back in the 80s. I was working for Hewlett-Packard at the time, but in my spare time I was designing a speaker system that used second-order LinkwitzRiley filters. Siegfried and I had lunch together at an HP conference in Amsterdam in 1985, but I didn’t realise who he was and obviously missed out bigtime on an opportunity to pick his brain!

So this time around I was not going to miss the chance to meet with him, particularly as I would be in San Francisco for a few days and Linkwitz lives just up the road in Marin County. He was generous enough to spend the whole morning of Boxing Day with me, showing me his laboratory and home office, and talking shop non-stop for a couple of hours. Afterwards we sat down to listen to his unusual creations: the open-baffle Orion loudspeakers and the point-source Pluto system.

Before I go any further, let me explain where Siegfried’s Orion system fits in in my experience of electrodynamic open baffle systems. AW Audio used a series of 120mm drivers and one tweeter in a two-way arrangement that involved some quite complex passive filtering and some physical time alignment between drivers. Emerald Physics uses a Berhinger DCX2496 as a digital filter and equaliser and several amplifiers to get the job done. Kyron Audio has an even more extravagant foray into the ‘box-less’ adventure (10 drivers per channel each driven by its own amp—a total of 700-watts of power per channel)!

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Australian

Siegfried Linkwitz (left) with Jean-Marie Liere.

SIEGFRIED LINKWITZ

An afternoon with a legend Jean-Marie Liere has been a fan of Siegfried Linkwitz’s crossover network circuit topologies and open-baffle loudspeakers for many years. In this article, he recounts how a recent visit to Linkwitz’s home in California came about, and his experiences listening to two of Linkwitz’s most famous loudspeaker designs, the Pluto and Orion.

InteRVIEW Linkwitz takes a more middle-of-the-road approach with his Orion system, now in its Rev.4 avatar, using only five drivers per channel (all made by SEAS) and each one of which is equalised, along with a three-way electronic filter (which he calls an ASP, short for ‘Analogue Signal Processor’). If you are prepared to build a pair yourself, the cost is said to be less than $4,000 for a pair. Just add your own amps, preamp and sources (Siegfried uses an Oppo BDP-95 Blu-ray player as his primary source, otherwise he uses audio files stored on his computer).

Before I tell you about my listening impressions, let’s first talk about Linkwitz’s Pluto speakers. Another favourite acoustic topic of mine has always been the elusive ‘point source’ speaker, the one that is supposed to solve a lot of our listening problems: stable image, absence of a ‘sweet spot’, coherent phase, time-aligned response and so on.

Cabinet size, shape and relative driver positions are all part of this equation and it is believed that all these limitations would disappear if (and it is a big ‘if’!) we could design a single, very small full-range driver with high efficiency and high power-handling. I guess you could call it the Nirvana of speaker design!

Next to dipole radiation, as with the Orion, I consider omnidirectional behaviour desirable provided the room has neutral acoustic Many attempts have been made at the point-source ideal, and the coaxial driver ‘a la Tannoy’, and the Uni Q from KEF (and even more recently, KEF’s ‘Blade’) are good examples. The Elipson spheres back in France in the 70s were another elegant solution to this problem. Other examples that spring to mind are made by Visme in France (the Cube), Audel in Italy and here in Australia by VAF (the i90)—all good examples of small pointsource designs. I was, however, completely unaware that Siegfried Linkwitz had designed a similar system in the 70s and abandoned it to concentrate on open-baffle speakers.

Fast forward to 2002 and Siegfried, in the course of another assignment, discovers a 50mm tweeter (made by Aura) that can reproduce frequencies down to 200Hz at the same time that he was also was toying with the idea of using a 127mm midrange driver from SEAS as a woofer. Put the two drivers together and the result was the Pluto: an omnidirectional speaker system, very close to being a point source, with built-in amplifiers, two-way electronic crossover (1kHz) and equalisation. As of 2012 the Pluto is in its

Above: Pictured at front is a pair of Linkwitz Pluto V2.1 active loudspeakers, with the piping left ‘unfinished’. Amplifiers are in the base. At the rear is a single Linkwitz Orion Rev.4 dipole loudspeaker.

2.1 revision. Siegfried was always clear about his design intentions for the Pluto. ‘My goal was to obtain an acoustically small source with wide and uniform sound dispersion over most of its frequency range. Next to dipole radiation, as with the Orion, I consider omnidirectional behaviour desirable, provided that either the room has neutral acoustics or that one listens to such speakers from a close distance,’ he says.

As you can see, the WAF (Wife Acceptance Factor) of the Siegfried’s Pluto design is appalling (though their small size and light weight means one could tuck them away in a cupboard and have them deployed when needed. Simply put a blindfold on, and listen!) but since these are a ‘Do It Yourself’

design, many DIYers around the world have come up with far more ‘spouse friendly’ designs. [www.tinyurl.com/pluto-photos] We started listening to the Plutos at Siegfried’s place (searching for familiar material, I found my favourite test track on Siegfried’s hard drive: Private Investigations from the Dire Straits album ‘Alchemy’) and I have to say that sound-wise, these are mind-blowing little marvels. The only time I noticed them at Siegfried’s place was when there was a bit too much bass and the piped woofer excited the floor-boards. I have not yet had a chance to listen to the Plutos on a concrete floor, but my guess is this problem could disappear… although remember we are talking about a 127mm driver in a sealed enclosure.

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