Infinity IRS Beta loudspeaker Page 2

Prior to the visitations, LA and I had done some preliminary listening to the Betas with the FET-10 preamp, the SA-1s on the upper-range panels, and a Mark Levinson No.23 and a dbx BX1 (in turn) on the bass towers. The sound was excellent but not exactly what I would call superb. When Nudell arrived, he insisted that we try using tube electronics. He even brought along one of his own Audio Research SP11 preamps (the man owns five of them!), just in case we didn't have one gathering dust in the corner. We didn't, Arnie Balgalvis currently giving house-room to our Mk.II SP11. However, we did have a pair of ARC's M-300 amplifiers on hand, and these were pressed into service until, after about half an hour, one of them blew a screen fuse and died. (Evidently a tube let go, but with eight of them in each amplifier, we were not about to take the time to try and figure out which was the culprit.) Fortunately, we had just taken delivery of a pair of the new VTL 300W tube monoblocks.

With the solid-state electronics, the sound was rather dry—more so, in fact, than with the same electronics through the Sound Lab A-3s. With the SP11 and the VTLs, the sound was transformed, becoming much more liquid, open, and musical. Did this mean the tubed electronics were better than the solid-state ones, or just different? In fact, subsequent bypass tests confirmed that the FET-10 was slightly more accurate than the SP11, but there was no denying that, with the SP11, the Betas sounded more musically natural. Nudell confirmed that the Betas, like Infinity's other top systems, were designed in conjunction with Audio Research tube electronics, so it was hardly surprising that they sounded a little less decent with solid-state electronics, no matter how "accurate" these may have been. This report, then, applies only to the sound of the Betas with some of the best tubed electronics available. I think I can state with confidence that the system must be so used in order to fully exploit its performance capabilities.

It must also be said that the Betas need a lot of breathing space. Because the woofers are capable of moving a hell of a lot of air, they should be placed well away from the room corners, to avoid as much as possible the generation of standing-wave resonances. The upper-range panels, too, should be at least 4' out from the rear wall, to permit their fullest reproduction of depth. Even more distance is needed in front of them. Because the panels are so high, and the drive-units occupy quite a large chunk of vertical space, the listening seat should be at least 8' away from them, and preferably several feet more, in order to give the wavefronts sufficient distance to integrate properly. Like the IRS Vs, these are simply not small-room loudspeakers; using them in anything less than a big room is a waste of much of their purchase price.

Four driver-balancing adjustments may seem to pose a formidable setup challenge, but the job is a lot simpler than it may appear. To begin with, the EMI controls have rather limited range—only about ±2dB from center, and the system is designed to be close to "right" with all of them centered. Usually, little change in any of them will be required, and the final tweaking should be done over a period of some weeks, using a wide variety of recordings known to have been carefully engineered for realism. (That rules out all product from major record companies.)

Woofer adjustment is by far the most daunting aspect of Beta setup, because of the number of interacting controls provided. With a claimed lower limit of 25Hz, and (by my own measurements, footnote 2) flat response down to at least 20Hz, these are quite capable of revealing stuff on recordings that you didn't know was there and were better off not knowing. I have heard and read criticisms of Infinity's bass towers as being sodden and heavy in quality, and, indeed, when Nudell was here, he set up the woofers for what I felt privately to be too much of a good thing. The instructions for the Betas suggest that one should never operate the subsonic (high-pass) filter wide open when listening to LPs, and with the system setup Nudell left me, the unfiltered bottom revealed all sorts of obnoxious rumbles, thumps, and thuds when playing analog discs.

But after he left, I turned down the bass level, moved the woofer towers about 6" farther out from the room corner, and shoved my sofa around until the low end I was hearing was as smooth and extended as I could get it. Guess what? The LF filter was no longer necessary on discs. Yes, there were still many records from which you could hear very deep noises in the background, but the noises were under control. They were neither prominent nor annoying, and even added a measure of realism to the sound because the noises were present during the original performance. The moral of this is that the most bass is often not the best bass (footnote 3).

Shortly into my private listening tests, I noticed that I was consistently running the preamp's balance control to one side of center. I had also been starting to observe that the system's imaging wasn't as good as it might have been. Phantom images were broader than life, and were rather unspecific in lateral placement. Playing a mono disc confirmed what I suspected: Center bunching was rather loose, and seemed to wander ever so slightly with changes in the music. I tried rotating the balance control from extreme to extreme, so as to listen first to one channel only, then the other. There was a definite difference, all the more obvious when using pink noise as a signal source.

All the drivers in both panels were operating, and apparently at the proper sensitivity levels, but it was not possible to make the two channels sound alike by adjusting their balance controls. It sounded to me as though the crossover between one set of LEMIMs and the EMIM above them was out of whack: either the LEMIMs were going out too far or the EMIM was going down too low. (The difference was too great to be compensated for with the individual driver level controls.)

Reversing the speaker cables, left for right, confirmed that this was not due to a difference in input signal; the problem remained in the same speaker. Interchanging the speaker units caused the problem to switch sides. The panels were unquestionably different. No wonder the imaging was mediocre!

That nobody had picked this up during the two previous days of listening seems hard to believe, as it was not at all subtle once I started listening for it. (Though Arnie Nudell's listening seat was off to one side of the central listening seat.) But there's the point. It has been said that audiophiles tend to hear what they expect to hear, but less recognized is the fact that we are often amazingly oblivious to what we don't expect to hear (footnote 4). But was the problem I had found a result of poor quality control, or a defective crossover part, or something else? John Miller messed around in both crossovers with a soldering iron while he was here; could he have miswired something? I may never know what happened. What I do know is that Arnie Nudell was horrified at the news when I phoned him about it, and got another (also modified) panel to us almost overnight.

A New Panel
I assumed that, when the replacement panel arrived, it would be a simple enough matter to determine which of my samples was out of whack. Just listen to the new one against the other two, with pink noise, and throw out the one that didn't match the replacement. What I found instead was rather distressing, to say the least. The new panel did not match either of the originals!

Instead of two different sounds, I now had three. The fact that the new one sounded midway between the other two made it impossible for me to ascertain with any certainty which of the originals was "right" and which was wrong. So I gave Infinity the benefit of the doubt, and culled for rejection the one which, in my judgment, sounded the least agreeable. Whether it was more or less typical of average production, I have no way of knowing. But I must say I was shocked at the variability I found between three samples of the Beta's upper-range panels. There is no way this system will ever be able to provide tight, natural-width imaging with that kind of QC!

Not surprisingly, the Beta's imaging was now substantially better than it had been, but it still wasn't as stable or specific as I have heard from many other speakers. I cannot believe my Betas are imaging as well as they could. But—and here is the point to continuing with the review—I also find it hard to believe they could sound much better than they do.

The word that most aptly describes the Infinity Betas is "awesome." These loudspeakers have a greater capability for standing one's hair on end than any system I have ever heard. I got goose bumps from recordings of solo accordion and harmonica, which is unprecedented, since I normally consider neither of them to be thrilling instruments to listen to. These speakers sounded as if they were made for big, dramatic musical works of the kind that inspired the high-fidelity movement from its very inception. (Why US audiophiles so often use their $20,000 systems, with 200Wpc of amplifier power, to listen to "original baroque instruments," solo guitar, and vocal sextets, is beyond my comprehension. Are Americans the only people in the world who would not see anything ludicrous about using a Stinger missile to kill a fly on the wall? footnote 5) The Betas had tremendous dynamic range, an incredible feeling of power, and a remarkable effortlessness during the loudest passages. The overall impression they gave of real, live music was something that must be heard to be appreciated.

Yet, quite unlike other immensely "impressive" speakers I have heard, these were equally at home with small-scale, intimate musical works. The Wilson Audio Beethoven violin-and-piano sonata recording sounded almost as realistic as the time Dave played the original tape through his factory reference system. In fact, the fiddle sounded a bit more natural to me through the Betas, which is to say it almost could have been right in the same room with me.

In terms of harmonic structure—accuracy of timbre—the Betas are going to be hard to beat. When something is this close to the proper tonality, then it becomes hard to describe its "sound" as such. Heard through the Betas, every instrument seemed to have just the "right" combination of weight and texture. Cellos, piano bass, and large brass instruments—whose sounds are most slighted by the majority of audiophile speakers—were reproduced by the Betas with breathtaking authority and power, and the effect that had on the apparent dynamic range of orchestral (and piano) music was quite dramatic.

Bass was positively awesome, with the capability of producing a huge sound from large-scale kitchen-sink works like the Mahler 8th and Mozart Requiem. Properly balanced and contoured, the Beta's low end seems totally absent most of the time. Then an unbelievably deep sound comes from the system, and the floor shakes. As the floor of my listening room is concrete, I know this is impossible, but there were times when I would have sworn it was happening. (What was shaking was probably my sofa.) And the quality of that bass was just as impressive as its quantity. Only the Synthesis subwoofers have equalled the Beta's low-end detail and focus in my listening room, and nothing I have heard has surpassed either of those in that area.

Oh yes (ho hum), the matter of soundstaging. The only systems I have heard that can touch these for soundstage presentation are a few mini-monitors. With good recordings, the stage almost literally "floats" between and behind the speakers, and the awareness of side walls beyond the speakers and the rear wall behind them is more definite than I had believed possible. Only in imaging specificity is the Beta less than impressive, and we know now why that is. (At least, in the case of my samples.)

Summing Up
Is the Beta a winner in every respect? Almost, but not quite. It does not have quite the "snap" of such full-range electrostatics as the Sound Lab A-3, which is capable of making sounds seem palpably, in-the-flesh alive. Without a direct comparison, this small deficiency is hardly noticeable; the Beta sounds very convincingly real. Under side-by-side conditions, the A-3s have the edge on realism. There is also a quality of brightness I hear from the Sound Labs which can verge on irritation under the wrong circumstances, but which contributes a great deal to the illusion of you-are-there reality when under control. This was one of the biggest differences I observed between the speakers. Whether the Sound Labs have too much of it or the Betas have too little is moot, but there is no doubt but that the Betas sounded more agreeable, and more musical under more conditions and with more program material than do the A-3s. The Betas have, if anything, a slight deficiency through this range (around 5kHz), which may conceivably account for the Sound Labs' superior aliveness.

In short, I love these speakers, and I cannot imagine anyone not being absolutely blown away by their performance. If you can afford them, and have the space, buy them. If I could, and had, I would. But if you do, be prepared to give up any smug preconceptions about the superiority of solid-state over tubes. A good transistor amp will work fine on the woofers, but only with the best tube preamps and upper-range power amps will these speakers deliver the remarkable musicality and realism of which they are capable. Also, make sure your panels are at least similar in sound. Perhaps my experience with three of them was unusual, but then again, it may not have been. Consider yourself warned!

The Infinity Betas' pricewise competition? Forget it. There isn't any that I know of.—J. Gordon Holt

Footnote 2: In fact, I could not tell what the Beta's lower limit was, because my oscillator does not range below 20Hz, and the system (in my room) produced as much output there as at 100Hz! The subjective effect of a very strong 20Hz is at once awesome and nauseating: awesome because of the impression of incredible power it gives, and nauseating because it apparently does nasty things to the ear's balance-sensing semicircular canals. I estimated that five minutes of exposure to it would have cost me my lunch.—J. Gordon Holt

Footnote 3: To be fair to Arnie Nudell, he set the bass level in Gordon's system using master tapes and CDs as reference material. The absence of subsonic spuriae with these sources, and the generally clean nature of their very low frequencies compared with LP, allows the subwoofers to be set higher without sounding unnatural.—John Atkinson

Footnote 4: I am reminded of a CES exhibitor some years ago who was proudly promoting a new noise-reduction system with a demo in which his decoder was switched out of circuit. For my part, I must confess that I have on occasion listened blissfully to several minutes of a stereo recording before realizing I had the preamp set to Mono.—J. Gordon Holt

Footnote 5: JGH! For shame! Thus to equate muscle with music is unworthy!—John Atkinson