Sound-Lab A-3 loudspeaker

The Sound-Lab electrostatic loudspeakers are legendary. Many serious audiophiles have heard of them, and rumors of their existence abound in audio circles. But, like gnomes, UFOs, and poltergeists, Sound-Lab loudspeakers are sufficiently hard to find that it is sometimes difficult to prove to skeptics that they exist at all. Well, I can now report that they do. As proof of this contention, I can point to the two which are actually occupying solid, tangible space in my listening room at this very moment. I have even taken a photo of them, which will be published along with this report if they leave any sort of an image on the film emulsion. (Many such apparitions do not!)

I have even met, face-to-face, and conversed with, a flesh-and-blood person who lays claim to being the designer of, and the president of the company which manufactures, the Sound-Lab loudspeakers. His name is Roger West, and he too is real.

Seriously, though, for a company which has been making loudspeaker systems for almost eight years, Sound-Lab maintains an extraordinarily low profile. It has never advertised anywhere, almost never submitted products for review to magazines (footnote 1), nor has it exhibited at CES for quite some time now (though their speakers were being used by both Rowland Research and Klyne Audio Arts at the 1986 Summer CES in Chicago). As a result, probably only a few thousand people have even heard of the company, let alone heard its loudspeakers. (After this issue of Stereophile is published, 35,000 people will have heard of Sound-Lab.)

Why such diffidence? Because Sound-Lab sees itself as a small company, staffed by people who believe in the product and take pride in their workmanship, and the Wests would prefer that it stay that way. Actually, I don't blame them; that kind of business, today, is a rare throwback to the dark ages, when running a business was supposed more to be fun than to be profitable.

But Sound-Lab's attitude toward the promotion of their products is so laid-back, it's a wonder they sell any loudspeakers at all. How come they're still in business, after eight years of virtual obscurity? Roger attributes this to the incredible quality of his products, whose owners are allegedly so pleased that they voluntarily promote Sound-Lab speakers among their friends. It's the old build-a-better-mousetrap idea, which seems to make great logical sense, but which has brought failure to almost every manufacturing concern that adopted it as a way of doing business. In my opinion, it is not the quality product that usually succeeds today, but the most flamboyantly hyped product. Roger West does not believe in hype, and as proof of his opposite view, he cites Sound-Lab's eight years of longevity and continued, if sluggish, growth. After having lived with a pair of his A-3 speakers for several weeks now, and scanning my notes for the review I am about to write, I think he should be making some contingency plans to cope with a sudden increase in orders: this review is going to be a rave.

First, though, a brief description of the A-3. It is a full-range push-pull electrostatic with a curved (semi-cylindrical) diaphragm. Unlike another curved-panel electrostatic, the similarly-sized (and $900-lower-priced) MartinLogan Monolith, whose low end crosses over to a 12" cone woofer at 100Hz, the Sound-Lab A-3 is a true full-range electrostatic, spanning the entire audio band down to a claimed 32Hz without the use of a dynamic woofer. Also unlike the Monolith, the A-3's diaphragm is not freely suspended between its four edges to produce a continuous curved surface. Instead, it consists of a number of small, vertically rectangular flat panels, arranged in a 90-degree arc. Each panel measures about 4" wide, and they vary in height from 2.5" to 7". The varying vertical dimension, and varying tensions on the Mylar film diaphragm, cause each radiating panel to resonate at a different frequency; careful choice of those resonant frequencies produces a controlled rise in overall response at low frequencies, which precisely (in theory, at least) compensates for the LF rolloff that normally occurs in a dipole system of this size. (This front/back cancellation effect has been described often enough in these pages that I won't go into it again here.)

The A-3 is large enough to impress, but, with its nicely patina'd walnut trim (with mirror-imaged grain patterns for the skirt strip at the bottom front of each speaker) and curved, horizontally ribbed black grille cloth, too attractive to offend or intimidate. Each speaker weighs 145 lbs, but (thank Heaven!) is equipped with 5 castors, so the speakers are a snap to move around in order to tweak locations and orientation. (Just warn the cleaning lady not to roll them out of the way for vacuuming. Tell her you want to accumulate dust under your loudspeakers.)

The Sound-Lab A-3 is rated at 88dB sensitivity (1W at 400Hz input, 1m from the speaker), but my sample pair didn't even come close to that figure. Assuming the manufacturer's 6-ohm impedance figure to be correct for midrange frequencies, 2.45 volts of input would be equivalent to 1 watt of power. I fed one speaker with a 400Hz 1/3-octave warble tone at that level, and measured the output at 1m from the grille with a General Radio 1565-A SPL meter (tripod-mounted, 70 degrees incident angle, 40" height, C-weighted, Fast). The reading was 76dB, 12dB below the rated efficiency figure! Thus, the 100W minimum recommended power is by no means an overstatement.

Unfortunately, the speakers would not, on low frequency test tones, handle even that much power without strain. With a warbled sinewave centered around 45Hz, both of my samples sounded as if they were starting to bottom out at a mere 94dB—with a measured input power of only 12 watts. On musical material, fortunately, rather than bass tones, there were no signs of audible stress until playback levels reached about 100dB (150W input power). This is just about the minimum volume needed to reproduce symphonic and operatic music at realistic levels, but it was barely adequate for clean reproduction of such very-wide-dynamic range recordings as the JVC Rozhdestvensky Shostakovitch Symphony 15. In other words, the large (+ Series) Acoustat speakers are still the only ones I have found that can handle large amounts of mid-bass energy, let alone the below-40Hz stuff.

Footnote 1: Sound-Lab had a somewhat scarring experience with a review in The Absolute Sound several years ago; the resultant drop in sales led to their extreme caution in seeking reviews.—Larry Archibald