Jason Victor Serinus

I couldn't resist the wonderful sounds of Louis Prima coming from the Green Mountain Audio room. Paired with Jaton Corporation’s Operetta AP2140A 2-channel Distributor amplifier ($1000, 140Wpc into 4 ohms, 70Wpc into 8 ohms), whose "processing filter circle eliminates 99.99% of noise at maximum volume," the intriguing-looking Green Mountain Calypso loudspeaker ($10,000/pair for the next month or so before the price increases 10–15%) was producing the kind of extremely smooth sound that draws you into the music. The speaker measures 88–89dB sensitivity, and utilizes a simple, first-order crossover to achieve "perfect" time-coherence. The midrange and tweeter are also adjustable forward and back for optimal sound in the listening position. The entire system, including the speaker, was wired with Marigo wire. I constantly find that Green Mountain's innovative designs produce lovely sound. Expect a whole new line of smaller, less-expensive speakers to appear on the Green Mountain website in another month or so.

I was utterly intrigued by the innovative speakers from Dr. Shelley Katz’s UK-based Podium Sound ($5995/pair). Katz produces panel loudspeakers that mechanically vibrate via electromagnetic drivers. Inherently free from phase error and less sensitive to placement than electrostats, they operate full-range without any filters.

Nelson Pass is up to good again. Following the wonderful sound of Ella and Billy I heard in the corridor, I discovered Nelson's prototype open-baffle speaker system. It sports both a Lowther PM6A full-range driver and a pair of SEAS W26 10" woofers. The 40"-high open baffle, which at this stage of the game is not intended to be a final design statement, has no side panels, only a central brace in the rear. The system was bi-amped, with the Lowther driver fed using a 60Hz, 6dB/octave high-pass filter feeding a First Watt F3 7Wpc JFET amplifier. The woofers were driven by a Pass Labs XA30.5 fed by a 12dB/octave active crossover. No equalization was employed. That the sound was so good was especially amazing, considering that the digital front end was pieced together at the last minute after the originally intended computer drive arrived minus its charger chord. I look forward to hearing the finished product.

The fourth annual Rocky Mountain Audio Fest is taking place this weekend at the Denver Tech Center Marriott. Registration was up 15% this year; snapped in the line in front of the registration desk at 9am was erstwhile Stereophile staffer Jonathan Scull (sensible suit, smart tie, and flashy glasses), these days a successful PR and marketing consultant.