Colin Whatmough Interview

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by Marc Rushton

6 years ago

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Colin Whatmough Interview

It was with great sadness that the Australian HiFi industry learned of Colin Whatmough's passing away in January this year. StereoNET spoke exclusively to Colin Whatmough back in 2007 and we thought we'd again share this interview to give readers an idea of just what drove Colin.

Colin Whatmough founded Whatmough Monitors in 1976 and that first year heralded the launch of Australia's first no-compromise loudspeaker, the legendary Whatmough Mk.II (a huge Transmission Line / Open Baffle hybrid). The Mk.II was the first speaker to incorporate lead lining in its construction which conferred significant dampening benefits. The 130kg speaker became a benchmark for Australian audiophiles.

Sadly, Colin passed suddenly on Tuesday 4th January, 2011. Colin's family, in honour of his work have announced they intend to continue operating the Whatmough Audio business.

StereoNET interviewed Colin back in 2007, and we thought we'd now share that interview with our readers.

Q: Thank you for agreeing to participate in the interview, Colin. 31 years in hi-fi is a long time - can you briefly tell us some of the highlights and pitfalls over this time? What did you do before you got into the loudspeaker manufacturing business?

A: Although we have won many awards both locally and internationally over the years, to me, completing the current Paragon is the highlight of my career. This design took over three years and is the speaker I have always wanted to design. While I only release designs which fulfill my standards at their price point and the segment of the market they are aimed at, the Paragons fulfill my standards full stop.

When I first went full time manufacturing speakers, I had just one model. The Mk IIs which were a large (refrigerator size) Transmission line bass/open baffle hybrid which sold for $2,500 (about the price of a family car at the time). These speakers had a cult following. This model was hand made in my garage taking approximately one month to build a pair. The drivers used were hand modified, the ribbon super tweeters were hand made using hand wound transformers which were wound with multi strand litz cable. Two strong people struggled to carry these speakers. I sold 18 pair of these speakers which kept me going for eighteen months, but this saturated the local market and sales then ceased. Strangely every pair of these went to a single guy and all went onto the second hand market when they married. The lowlight of my career was returning to the 9 - 5 workforce at this time.

For the next few years I worked a full time job in the computer industry and still spent at least 40 hours per week designing and manufacturing speakers.
It became obvious at this time that if Whatmough Monitors was to survive, I would have to manufacture more commercial and affordable models.

Q: What is your preference in music?

A: My favorite music is swing jazz, although I also enjoy classy rock (Clapton, Knopfler etc) blues and classical music.

I enjoy live classical concerts which I use as my reference when designing. Classical music is the only music I can hear live and unamplified. There is a richness to live classical music that good quality Hi-Fi equipment can reproduce, but the PA speakers and electronics required used at concerts cannot approach.

Q: Most of your speakers have low nominal impedance (all your Signature speakers are rated at 4 Ohm) with relatively modest sensitivities (between 85-91 dB/W/m). Does this limit the type of amplifier that would ideally drive your speakers? No valve amps?

A: We have plenty of customers using valve amps, most of which have 4 ohm taps. We even have one using a pair of 18 watt Silver Nights to drive Paragons. Since the Paragons include an electronic crossover and have active bass they are less demanding power wise than a full range speaker of similar efficiency. I personally would prefer more power for the paragons and have used 45 watt 300B Canary mono blocks which can drive the Paragons well.

I do not like the compromises required to achieve high efficiency such as horn loading speakers with its inherent coloration or the coloration associated with cone speakers using very low mass cones to achieve high efficiency. As a result I am not a fan of 8 watt single ended 300B amps. Sure they can sound nice, but they restrict the type of speakers you can use or the type of music you listen to. I believe 211s or better still 845s are the way to go for single ended amps.

Q: What equipment do you use to demonstrate your speakers?

A: We use electronics by Canary Audio, Cairn, Electra, Marantz, Pioneer, Prima Luna, Primare. Cables are by Cardas (on Signature speakers) and our own (Whatmough) on our other speakers.

Q: What do you find to be the most critical component to optimize when it comes to loudspeaker design? Drivers, cabinet, or crossover network?

A: Without doubt the most critical component is the crossover network. For us, this typically accounts for 70 - 80% of the design process. That being said, if the cabinet or drivers are not up to scratch, the design will still be flawed.

Q: There are many different types of loudspeaker - electrostatic, dual concentric, open baffle, and so on. You have obviously chosen a fairly conventional boxed design. What are the advantages of this type of design over other loudspeaker technologies?

A: My first commercial High End speaker used Transmission line bass, open baffle mid-range and our own ribbon tweeters. I persevered with open baffle speakers for years. While this design approach has its benefits, particularly their open sound, they also have their draw-backs (poor imaging and difficult to control panel resonances). Their biggest drawback is that their size is generally not domestically acceptable and that they need to be positioned well out from the walls.

Most of our speakers use curved cabinet sides which are less resonant and also minimize internal standing waves. They are also extensively braced to minimize cabinet resonances. This dramatically improves clarity and transient response. The sonic difference between a speaker using a well designed enclosure and a similar speaker using mediocre cabinet is huge.

Some electrostatic speakers sound stunning when reproducing acoustic guitar or chamber music but fall down when reproducing rock or full orchestral music. Because of my wide musical tastes, I think a good speaker should sound good whatever your musical taste. When it comes to a speaker that can handle all musical forms, a well designed multi-driver cabinet speaker has well and truly stood the test of time.

Q: Active crossovers are said to offer many advantages over passive crossovers. Yet yourself and nearly everyone else in the industry overwhelmingly favor passive crossovers. Apart from the obvious reliability of passive crossovers (for example, a clipping amp will have a crossover to protect the drivers - run them actively and the distorted waveform will melt the tweeter), are there any other advantages? Would you rather use an active crossover if you had the choice?

A: The main advantage of active crossovers is in the bass as they eliminate the need for an inductor in series with the bass driver and so take full advantage of an amplifier’s damping factor. This is one reason we use an active bass for the Paragon. This is not so appropriate on less expensive speakers as they could then only be used with a pre/power combination. A good electronic crossover would also increase the cost considerably. Many active speakers with built in amps use low quality amps to keep the cost down and are often forced to use class D with switch mode power supplies to reduce the volume the amp takes up.

Electronic crossovers do not have the same advantage when crossing over at higher frequencies. The extra electronics in the signal path often has a more detrimental effect on the sound then a passive crossover network would. Further more, the cost of a quality electronic crossover and extra amplification required puts such a system out of the reach of most people.

By the way, a passive crossover offers no protection to tweeters against harmonic distortion unless a protection device such as a poly switch is included. The crossover, electronic or passive only rolls off the lower frequencies (below 2 or 3K) and maybe some EQ. The harmonic distortion that takes out tweeters will be above this crossover point.

Q: What is the advantage of the ring radiator tweeter over other designs, such as conventional tweeters or ribbon tweeters? Have you experimented with other tweeter technologies, such as the AMT?

A: Over the years, I have experimented with just about every tweeter imaginable. One of the most interesting was an Audax tweeter which looked like a gold dome, but was actually a piezo electric film which was pressurized from behind by an inert gas. This film expanded or contracted when fed a signal so that it acted like a perfect massless dome. It sounded fantastic until the temperature changed. The efficiency would drop by 3 - 4db on a cold day and rise by a similar amount on a hot day.

I used Focal inverted dome tweeters for many years. While these were airy and open sounding, they always had a hardness to them. I was forced to lower the Tweeter level by a few db to make them more livable, but then lost some of the air and openness they were well known for.

Soft domes usually lose detail because the centre tends to move out of phase with the outside, though I find this more acceptable to the hard sound of most metal domes.

Ribbons can sound delightful at very high frequencies, but not so good at lower treble frequencies. They also have a problem when metal fatigue sets in, typically after around twelve months. They tend to lose the air and openness, which is why people use them in the first place. We stopped making our own ribbon tweeters for this reason.

For me, ring radiators have fewer vices than other tweeters I have used, particularly the Scan Speak version. While the Vifa version is not as revealing as the Scan Speak, it is excellent for its price and doesn’t show up the shortcomings in the lower priced electronics likely to be used with it.

Q: In your view, what is the biggest source of loudspeaker coloration? What steps have you taken to minimize this?

A: During the last 31 years, drivers have improved dramatically. I spend a great deal of my time sourcing and evaluating drivers. When I started manufacturing, most drivers were paper coned which tended to sound smooth but woolly and ill defined. About that time a plastic material (Bextrene) became popular. This was more detailed than paper cones of the day, but it sounded quacky. Since then I have used kevlar, carbon fibre, fiberglass, nomex and polypropylene, to name a few with varying degrees of success. Today most (but not all) of our speakers use paper cones. These are vastly superior to the paper coned speakers of 30 years ago.

Q: Narrow baffle speakers are said to have a more wider high frequency dispersion, whereas wide baffle speakers have a more narrow high frequency dispersion (i.e. tend to "beam" more). Thus, narrow baffle speakers would tend to have more problems with room interaction. Your speakers are fairly conventional in that they are narrow baffle. What are your comments about this?

A: It is true that wider baffle speakers tend to have a narrower dispersion pattern; however they suffer more from a small sweet spot. It sounds good if you keep your head still, but if you move your head a little bit to the left, or a little bit to the right, the imaging suffers. A narrow baffle speaker simply images better - the image is more precise, more three dimensional, and the soundstage is much wider. My first commercial high end speaker, the Mk. IIs were large and wide. Having a transmission line bass and an open baffle mid-range, they sounded open but they did not image well. In particular they did not portray a sense of scale: everything sounded big. Even a solo vocalist seemed to have a mouth the size of Luna Park. Many large high end speakers today still have this problem. This imaging problem wasn’t only caused by the width of the speaker, but that was a major factor. Although open baffle speakers do sound open, they have many other inherent problems. A speaker cabinet has to be narrow to achieve the open sound of an open baffle speaker.

Q: Many speaker designers are finding it more difficult to source drivers with a number of companies now refusing to supply OEM drivers. Focal and Dynaudio come to mind. As a result, some speaker designers are turning to car audio drivers to put in boxes. What are the main differences between car audio drivers and drivers designed for home audio?

A: The main difference is in the woofers. A car audio woofer has a large gap between the voice coil and the magnet. They do this because the drivers are in an environment where they may be subjected to vibrations and sudden shocks. You do not want the voice coil to collide with the magnet, as this will damage the woofer. Also, car speaker manufacturers spend a lot of money machining and finishing the speaker frame and magnet assembly to make it look nice as it will be on display. Several hundred dollars will be spent on the finishing alone. This is of no benefit for home audio, as the drivers will be hidden inside the cabinet.

Increasing the gap between the voice coil and the magnets will reduce the Bl (force factor) and increases the QTS of the driver. A larger gap reduces the flux density which has the same effect as reducing the magnet size. The driver ends up having much less bass control. This lack of bass control is much more noticeable in a large room than in a car.

The other disadvantage with many car speakers is that many manufacturers don’t take the sound quality as seriously as with domestic speakers. I believe that visual quality is considered a higher priority than sound quality for most car audio manufacturers.

Q: Your Paragon is your "statement" speaker. Could you tell us a little more about what makes this model unique?

A: I spent three years designing the Paragons. During this time I used many configurations and many drivers.

The basis of this design was to use an active sub bass crossing over at 80 Hz. This meant I could use sealed enclosures above this frequency as I no longer needed the extra bass extension of a reflex enclosure. As a result, these speakers have lower distortion and improved transient response over a vented design.

The bass, mid-range and treble enclosure is exceptionally well braced, resulting in no discernable panel resonance. The sub bass enclosure uses two long throw (36mm linear point to point) sub-bass drivers in a fully balanced configuration. This also has no discernable cabinet resonance and so does not transfer any resonances to the bass/mid/treble enclosure which sits (via spikes) on top of it.

The electronic crossover supplied with this system rolls both the bass and sub bass off at 100db per octave. The sub bass drivers receive virtually no upper-bass or mid-range while cone movement is virtually eliminated in the upper bass units.

Internal wiring is Cardas, Hovland film and foil capacitors, crossover networks are point to point hard wired and isolated in their own enclosure.

These speakers, while being very smooth and refined, have exceptional transient response. The Paragons do not compress in the bass as the volume increases like most speakers. While many “high end” speakers can sound lean and dry, the Paragons still portray the sound rich sound of a live (unamplified) concert.

As a result, the Paragons sound very natural with good recordings, but will show up bad recordings. Many Paragon owners find that some of their favorite recordings actually complimented flaws in their previous speakers and are actually not as well recorded as they thought, while other recordings they considered OK are actually superb. One such customer favored recordings that were fat in the bass as they complimented his previous speakers which were lean. Yet other highly regarded recordings always sounded thin on his old speakers. On the Paragons these recordings sounded great, while the recordings that suited his old speakers were now obviously fat.

Q: How has your experience with the Whatmough Paragons diffused down to the other speakers in your line-up?

A: The Whatmough Paragon has an active, balanced band-pass sub-bass, with a 3-way sealed enclosure on top. A sealed enclosure is inherently cleaner and more detailed than a vented enclosure at the cost of bass extension. Most models below the Paragon, such as the 505s and the P33s, are ported designs. These designs are suitable for use in stereo systems which may not necessarily include a subwoofer. The Whatmough P-AV1 system is a dedicated 5.1 (or 7.1) using 4 or 6 P12s and a P2 centre channel speaker all of which are sealed. This system also uses an Impulse subwoofer. The bass management of the receiver used will send bass below 80Hz to the subwoofer and only frequencies above 80 Hz to the main speakers. While this arrangement is not unique to Whatmough, I was inspired by the results with the Paragons to take this approach.

Q: How has home theatre affected the market for high end two channel speakers?

A: I doubt there would be a viable hi-fi industry, at least in Australia and the US if it wasn’t for Home Cinema. Many audiophiles berate home cinema, but in fact without it the hi-fi industry may have disappeared altogether. The 1970's were the heyday for hi-fi: there were probably a higher percentage of audiophiles then than at any other time. In those days most guys on entering the work force had two ambitions: - to buy a car and to buy a sound system. With the faster lifestyle of modern living the sound system seems to have dropped down the list of priorities.

The problem then as now, is that Stereo tends to be anti-social from a family point of view. While dad is listening to his stereo, the rest of the family are watching TV or whatever. When we sell stereo gear, at least 95% of the buyers are male and most come in to audition on their own. With home cinema, a large percentage of our customers come in as couples. Often both the husband and wife are equally enthusiastic and they go home and enjoy the system as a family.

Some of those into home cinema will get converted back to or will discover quality two channel audio. I believe high end audiophiles make up less than 1% of the market.

Q: Any other hobbies, Colin?

A: I am a very keen fly-fisherman (trout), and enjoy photography, kayaking and swimming.


Colin's passing is a massive loss to the HiFi industry worldwide, and he will be sadly missed by all those who have known and worked with him. StereoNET passes on our condolences and best wishes to Colin's family and friends.

Colin Whatmough 1950 - 2011

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Marc Rushton's avatar

Written by:

Marc Rushton

StereoNET's Founder & Publisher and still buried deep in the review room auditioning everything from docks to soundbars, amplifiers to headphones. Marc also founded Melbourne's International HiFi Show.

Posted in: Hi-Fi Industry
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