David Wilson: WAMM!! WATT?!? WHOW!!! (& the Puppies!) Page 2

Atkinson: Are you making very big adjustments?

Wilson: Very subtle adjustments. Now this is something I don't understand exactly why it should be so. With the Series 1s through the Series 4s, there was a range of adjustment of 2 or 3dB from WAMM to WAMM in different rooms. So the assumption could be reasonably made that what was happening was that the system was being equalized to match the characteristics of the room (which is what most people think equalization is for). As it turns out with the Series 6, of which there are probably 14 or 15 in the world today, all of those systems—regardless of the room, regardless of the associated equipment, regardless of the listener—are within 1dB of each other over the full 11-octave range of the equalizer. (This is one reason why John Curl and I feel that it's appropriate to build a simpler equalizer which will have balanced throughputs for the Series 6.) What I think is happening is that the equalizer is now being used to make fine-tuning adjustments between the modules within the array and to match them to the particular sonic characteristics of the associated electronics and cables...

The WAMM was originally intended as a reference tool, not as a product, so its adjustments are very critical: if changes are made in the system, you can clearly hear the effect of those changes. That's particularly true in the focal point of the system, which is a defined listening area that the user has identified and chosen to use for doing the most critical listening. With the earliest WAMMs, the Series 1s and Series 2s, that usually was the place where the system really truly sounded the best. Indeed, in some instances it was the only area where it sounded really good. For some reason with the Series 6s, what we find is that the system indeed sounds its most accurate at that point, but it sounds quite good anywhere in the room, which is the way I like it to be. I can't exactly explain why this should be. It could possibly be that the associated equipment has also improved over that 9–10 year period. Dramatic improvements.

Atkinson: Particularly in amplification.

Wilson: Amplification and cables: who would seriously put Fulton Gold speaker wire in their systems today? And yet at the time, that was considered the best. And hideously expensive at $4 a foot! The good old days! [laughs]

Atkinson: With the way the WATT has evolved and with the development of the Puppy, is it fair to say that you tried to make a speaker system that would allow its owner to get a good sound with a much wider range of matching equipment and conditions?

Wilson: Yes. The WATT, like the WAMM, was originally designed as a reference loudspeaker tool, because, believe it or not, Wilson Audio is primarily a recording company.

Atkinson: You wanted to be able to hear exactly what you were doing with microphones.

Wilson: Primarily in the areas of transparency, of image placement, and of dynamic shading. I had determined that those three areas were the most important things that I needed to hear as I was listening to a microphone feed. Low-frequency response extension and quantity would have been nice, but it is physically impossible to get large quantities of great-quality bass out of a small enclosure. So I decided to forget it, not even to go for it with the WATT.

The Series 1 WATT was overdamped. When I designed it in the fall of 1985, the test equipment that I used didn't allow me to do the level of analysis that I can now do in terms of reflections off of internal structures and things like that within the enclosure. My approach was therefore "when in doubt, damp it," and the Series 1 WATT was quite lean in its tonal balance. It had the very pronounced impedance dip at 2.1kHz—which is necessary to control a dustcap resonance in the woofer—which Martin Colloms had found in his Stereophile report several issues back (footnote 1).

The Series 2 WATT addresses the impedance dip so that it is about one third what it was in the Series 1. The impedance dip is down to about 1.6 to 1.8 ohms instead of less than half an ohm. Amplifiers can be a little more comfortable with it. (I still don't know if it would be acceptable to the British sensibility of linear impedance curves.) The overall sensitivity of the system is slightly higher. The electrostatic and the electromagnetic alignments of the crossover elements are more elegant than they were with the Series 1. The response is simply more linear, the crossover allows almost twice as much current to be delivered to the woofer, and we've been able to reduce some of the acoustical damping in the enclosure, so that the enclosure is working more now to support the low frequencies; there are also more low frequencies to begin with with the Series 2.

The Series 2 WATT, after a year and half to two years of experience with it, is a more complete, a more accurate reproducer than the Series 1 was, while, I believe, retaining all of its virtues (footnote 2). It's simply a better device.

Atkinson: But without losing its utility as a tool?

Wilson: Right. Peter McGrath uses Series 2 WATTs, Joseph McGee uses them with the Los Angeles Philharmonic Orchestra, Sean Murphy and James Horner use them exclusively in film scoring and editing work.

Atkinson: I understand that the WATT/Puppy is not a conventional satellite-and-subwoofer system but rather should be regarded as a full-range three-way design. The whole problem with subwoofers, as I see it, is that with the exception of the Celestion System 6000 and now the WATT/Puppy, they're not designed and installed by the designer of the main speaker. If you did have a subwoofer which was optimized by the designer to mate with his own full-range loudspeaker, then that would ensure that the system would work as a whole, that it didn't feature what Ricardo Franassovici of Absolute Sounds in the UK refers to as the "fat potato sound," the lumpy bass dragging along behind the mids and highs.

Wilson: The Puppy is designed to take what was originally intended to be a highly compact, location reference speaker and convert it into a three-way system which can be put into a domestic or professional environment and not be moved around. It is intended to extend the low-frequency response of the WATT, expand its dynamic capabilities, flesh out in a highly coherent way the lower midrange, the "warmth" region, and to actually improve the linearity of the overall system.

It should be noted that the Puppy is a woofer, a compact, high-speed woofer, not a subwoofer. I spend a lot of time in the design of a product visualizing. I spend more time, I think, visualizing the product—what I want it to sound like, what I want it to look like, how I want it to be perceived—than I do actually designing it. And one of the decisions that I had to make was, okay, how much low-frequency extension do you really need in a system like that? As you know, a lot of people had been using other brands of woofers with the WATTs, with mixed results: sometimes very good and other times not good at all. It was a variable situation, and while there was a part of me that was content to leave that situation alone and focus more on recordings and on other things, another part was looking at the bottom line on the accounting sheet and saying, "you know, some of our dealers are not able to sell the WATT because they can't sell an acceptable woofer with it. Either because they don't carry the line, or because whatever manufacturer it is, they can't supply, or whatever."

One of the problems that we had seen was that the WATT, by its nature, is very fast and articulate, lean but very fast. But the woofers that had generally been employed with the WATT tended to be much more sluggish. They had their own character, which might work well with another system; or, if crossed over low enough, could serve very well as a subwoofer. I'm not criticizing these woofers, it's just that they were the Jones and the WATTs the Browns.

The number-one sonic priority therefore became to achieve a seamless blend with the WATT. The number-two priority was almost not even in sight, it was so much less important. Of course, if you do manage to produce a woofer which is fast enough to blend seamlessly with the WATT, whose harmonic structure and amplitude response meets up perfectly with it, then you've gone a long way toward achieving your final goal. What remains is, how loudly do you want it to play? How efficient do you want it to be? How low do you want it to go in frequency?

So I started looking at the question of low-frequency extension. Well, to get 20Hz—let's just pull 20Hz out of the hat because everybody else does—to get 20Hz out of a box the size of the Puppy...We knew that it would be that size because the WATT likes to be at a certain height for most listening environments, and you don't want the woofer to be grossly wider than the WATT, you don't want it to be grossly deeper; basically, your size is pretty much established. To get 20Hz out of a system that size, you'd probably end up using a single, small, very-high-compliance woofer with a fairly massive cone, a fairly small magnet, and what you would get would be a measured 20Hz output at low levels. It would be sluggish, inefficient, and wouldn't have good power-handling capacity; its dynamic characteristics would not at all match those of the WATT.

I consider that too high a price to pay for 20Hz. So for about the first half of 1989 I had several conversations with dealers, users of WATTs, and recording engineers on the question of how low do you have to go for most listening? For a sensitive listener to achieve musical satisfaction out of a wide range of music? The consensus was that if you could achieve 40Hz with absolute authority, then that probably would be enough. So in my mind, I established 40Hz as an acceptable low-frequency extension. Meaning, of course, that it's not a subwoofer. It's a woofer. (We already make a subwoofer, the WHOW.) And if our premise was correct, if that 40Hz is going to be enough for 95% of the people, then that'll be fine and they don't have to worry about spending the extra $10–13,000 to get that extra 20Hz to 25Hz of bass.

Footnote 1: In Vol.11 No.2, February 1988.—John Atkinson

Footnote 2: David Wilson assured me that all the Series 1 WATTs can be updated to Series 2. Overseas, Wilson Audio sends a kit of parts. In the US, the owner returns the speakers to Wilson Audio; the modification is done, the speakers recalibrated, and then returned with a new warranty.—John Atkinson

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