Wilson Audio Modular Monitor (WAMM) loudpeaker system Page 2

It is this acceleration of aural intensity which produces a kind of rapture in the music-lover—Do I wax too poetic? Are you checking the cover of your magazine to see if it's really Stereophile?—that the WAMMs do uniquely well. As you can see, I was bowled over. As an equipment reviewer I would like the WAMMs for their cleanness of presentation, their tonal neutrality; as a sensual human being I would like the WAMMs for their ability to present realistic orchestral dynamics.

It's hard to assign one specific cause to above effect. I suspect that the key decision was to use $8000 worth of cabinetry and driver to cover at most three octaves. This not only reproduces those octaves well—it frees up the rest of the system to perform in a dynamically satisfying way. Then again, the use of two KEF B139s per side, mounted in extremely well-braced boxes, to cover a frequency range that begins at 50Hz, is the kind of overkill that effects the freedom referred to above. And not to be dismissed is the all-out commitment of the designer together with his resourcefulness, the willingness to make a product that obviously will not sell in the hundreds of units and might have a hard time selling at all.

That he was willing to use modified Braun satellites and a Crown equalizer, two products that won't win him status points amongst high-end aficionados, in his quest for aural realism is to Dave Wilson's credit. And you shouldn't think that his is a commercial path lined with easy money. It's probably harder to make money producing a state-of-the-art speaker system than any way you could choose. Just ask Infinity how much they've made producing IRSes.

Not as much as they make selling $77 speakers, I'll wager.

With the WAMM system, however, you don't just get a bunch of boxes with a nail-puller and start unpacking. If you buy the system through a dealer the dealer ensures that you have adequate associated equipment (a word about that, later) and does the basic unpacking of the WAMMs. When all this has been done, Dave Wilson flies in and spends two days doing the final setup and calibration of the WAMM system.

There are basically five steps: (1) physical location in the listening room; (2) time-alignment of the individual driver units with respect to the listener's specific location in the listening room; (3) basic adjustment of the equalizer to compensate for room anomalies and particular associated equipment; (4) fine adjustment of the centerpoint of each equalizer band using a unique Wilson Audio method; (5) and final adjustment of the equalizer for user preference. The two most interesting steps are (2) and (4).

One of the unusual design aspects of the WAMM system concerns physical adjustability of the drivers. Time-Alignment of drivers is a name copyrighted by E.M. Long, but the basic procedure (under some other name) can be used by any speaker manufacturer. The goal is to ensure that the successive wavefronts of a complex musical waveform produced by more than one driver will arrive at the listener's ear at the same time.

In a rudimentary example, one can see that the so-called acoustical center of a 15" woofer and a 1" dome tweeter mounted on a flat speaker baffle will arrive at the speaker's ear differentially in time simply because the woofer's voice-coil, from which the basic signal emanates, is a significant distance further away from the listener than the tweeter's voice-coil. In fact, calculating the arrival time of an acoustic wavefront from a particular driver is a complex process wherein minor changes in crossover and driver design become important.

Dave Wilson is able to solve this problem in a fairly straightforward fashion due to the fact that his drivers, each in their individual enclosures, can be moved from front to back, and because his listener chooses one ideal seat and speaker location, to which Dave can customize the speaker orientation. Other designers must assume a specific listener distance from the speaker and height off the floor—probably most listeners are not actually located where they "should" be, and so the time-alignment for those listeners is inaccurate. Specifically, Dave mounts a microphone at the height and location of his listener's ear and aligns each driver starting with the midbass unit so that a test pulse arrives at identical times from the different drivers (both midrange units, at different heights, and the tweeter panel). Since the ear is insensitive to low-frequency arrival times, the placement of the subwoofers is made so as to excite room resonances as little as possible, or following aesthetic considerations.

The other fascinating adjustment by Dave Wilson concerns the adjustment of the centerpoint of the equalizer passbands, a process he calls "vowelization" or "vowelling". With the equalizer set for approximate amplitude correction, Dave puts on a master tape of Sheryl Lee Wilson, his wife (see the cover of Vol.6 No.2), singing. He then adjusts the centerpoint of the midrange bands on the equalizer, creating an "oooh–aaah" effect until he arrives at the point which to his ear most accurately reproduces his wife's voice—a source with which he is quite familiar.

Great idea! Dave has promised to write an article for us on this technique, which should be usable by the general audio public (provided they own a Crown equalizer with its adjustable centerpoints)—unless of course the wife's voice is not a source of delight. In that unlikely instance, the equalizer might be used to eliminate a certain stridency in the offending wife's voice—which stridency would no longer be available in your favorite Shostakovitch violin sonata!

An Analysis Tool
An interesting aspect of my visit to Wilson Audio was the use the WAMM system can be put to for analyzing differences between associated components. First, the components we used: (1) source material was Wilson Audio master tapes played on a modified Revox A77 and analog records, primarily from Wilson Audio, as played by an EMT/van den Hul cartridge mounted in a Technics tonearm on an Oracle turntable; (2) pre-preamplification through a Sig Modes-modified "Powerlight 3" head-amp; preamplification through the Spectral DMC-10 (Beta); amplification through two Krell KMA-200 amplifiers and the BEL 2002 amplifier.

As a test of the system's resolving capabilities, as well as two highly rated cartridges, we compared the van den Hul EMT to the original master tapes as well as to the Accuphase AC-2, which would also be compared to the master tapes. A switching device was rigged up so that the two cartridges could be played through the same preamplifying device. Methodological problems lay in the use of two different turntables and tonearms, as well as a switching device whose changes were noticeable through a fairly loud click.

Most profoundly noticeable was the system's ability to resolve small differences. We were fortunate to have on hand master tapes of the discs we were listening to. Outside of PCM-F1 copies of master tapes (to which I imagine Dave would object) I don't know of a way to compare a disc to its master tape in a home situation.

The results? Well, the van den Hul EMT produced a very faithful recreation of the master tape. I'm astonished that it's possible to amplify the signal from a tape, operate a cutting stylus to create a lacquer, make a mother and then a stamper, stamp a vinyl disc, turn it on a turntable, play it with an electro-mechanical generator interacting with the semi-fluid vinyl, and run it through an RIAA correction circuit with so little degradation. The test was neither single- nor double-blind but I could easily have become confused between the cartridge and the master tape. There were small differences in the amount of detail available, but only repeated playings of the comparison would reveal this. Spectral balance was virtually identical with the exception of the lowest bass, where the van den Hul EMT was slightly deficient.

How did the Accuphase AC-2 do? By comparison to either the EMT or the master tape, there was a constant amount of mid- to high-frequency distortion added to the music, as an overlay. To describe it as an extra amount of sibilance gives an accurate idea of the sound. This distortion was readily evident comparing to either the master tape or the van Den Hul.

Summing Up
So, what do we have with the WAMMs? For me it's the most enjoyable speaker system I've listened to, and significantly valuable as a diagnostic tool. This is particularly true when evaluating cartridges, preamplifiers, turntables and other source material. I urge caution in using the WAMM system, or any particular speaker system, for evaluation of amplifiers. Time and time again we at Stereophile have seen an extremely good amplifier fall down with some particular system, and conversely have found combinations where an otherwise ordinary amplifier mates very well with a particular speaker.

In this respect the WAMM is not different from other speaker systems. In matters of clarity and revelation of detail the system may be unsurpassed; with respect to tonal balance the WAMM is a special load for an amplifier, and results obtained with it may well not be universally applicable. Moreover, the WAMM's use of an equalizer, which is presumably adjusted to accommodate the varieties of amplifier used, should put on an equal basis many otherwise different amplifiers. Nevertheless, I lust after this speaker system for use in evaluating related components.

Is it worth the money? Surely not, for any person whose income or net worth is less than stratospheric—and certainly not for one who has to be concerned with mundane subjects like mortgage payments and mere cost-of-living salary increases. But my dealings in the expensive automobile business have revealed to me that there is a significant number of Americans (and non-Americans) to whom large amounts of money are merely digits to be entered in their checkbook—they don't worry about the balance, which apparently takes care of itself. To such people, or possibly to an absolutely fanatic though financially more normal audiophile, I would certainly recommend an audition of the WAMM speaker system.

Aiming for such heights in audio componentry is a bold first move for David and Sheryl Lee Wilson, and I wish them all the luck in the world. I have my reservations about their most recent $7000 price increase (footnote 1), though it may not put off any truly potential buyers. About one thing I have no reservations: I can think of no person or company I would prefer to have supporting and warrantying such a substantial investment.

Footnote 1: Just before press time we learned that unfortunately (?!) the price of the WAMM system will go up to $42,000 in August 1983. Now come on, Dave and Sheryl Lee, isn't that a bit much? Wilson Audio Systems will also supply the unadventurous, and extremely wealthy, audiophile with a complete music system including amplification, preamplification, and disc-playing (not Compact Disc playing, you can be sure) equipment for a mere $89,500. Can't you remember the hue and cry raised when Grado's first Signature cartridge came out for $300?—Larry Archibald
Wilson Audio Specialties
2233 Mountain Vista Lane
Provo, UT 84606
(801) 377-2233

remlab's picture

What A MMess.

corrective_unconscious's picture

That photo looks more late 60s or early 70s than early 80s, but that's probably Utah versus coastal culture.

Jceaves's picture

Yes, the speakers are the monster. Smile for Mr. Holt, son.