Infinity Reference Standard 1B loudspeaker J. Gordon Holt Returns
In my review of the RS-1B (Vol.8 No.4), I commented on that speaker's tendency to exaggerate grundge in the program material by adding what sounded like extremely narrow response spikes in the mid to upper treble. Since then, Infinity provided us with a modification kit for the passive crossover network feeding the mid-tweeter. The modification involves changing a potentiometer, and adding a resistor, capacitor, and choke to the crossover. It's more difficult than the instructions imply because the leads on the cap and coil were too short to enable the parts to go where they have to go! To simplify things, add 2" of insulated wire to both ends of each part before you try to install them.
The modification eliminated virtually all the roughness noted in the original review, and didn't seem to do anything detrimental. The nature of the modification confirmed that my earlier guess had been correct: the crossover from mid-tweeter to high tweeter has been moved from 8kHz to 6kHz, rolling off the mid-tweeter before it gets into those frequencies where it starts to sound rough. (All tweeters—except essentially massless ones, like the Plasmatronics—develop a series of peaks through the range where their high end rolls off.)
The RS-1B is still one of the most awesomely stentorian speakers I have heard, with an unsurpassed (in my experience) ability to reproduce both rock and big, dramatic works, extraordinary low-end range and detail, and as realistic reproduction of soundstage depth and width as any system I've heard. It now does those same things, but without the slight roughness I heard before.
I commented in my original report that this system does not do as well on small-scale music—chamber works, instrumental solos—as on massive material. That is no longer the case. Neither is the RS-1B as amplifier-sensitive as it was. In its original form, we found that only tubed electronics could be used for the midrange and tweeter panels; otherwise the sound was quite dry and almost gritty. The modified version works fine with any really good amp, though I unhesitatingly confess my preference for the way the RS-1Bs sound with tubes. In my opinion, this system is now close to being the best loudspeaker available—without going completely overboard in price (the WAMMs at $45,000 or Infinity's own IRS-III at $32,000).
The RS-1B still doesn't sound as alive, nor as delicate at the extreme top, as some electrostatic systems, but that does not alter the fact it's one helluva speaker system!
Incidentally, AHC's independent report on the RS-1B made no mention of the roughness I heard. Was he deaf? Nope. His sample came off the production line later than mine, and included the change which I later added (it's now standard). And Infinity had the effrontery to label my mod kit the "J. Gordon Holt Electrostatic Mod," as if I required speakers tailored to my finicky taste—when they already knew about the problem and had been shipping modified speakers for some months!—J. Gordon Holt