John Atkinson

After a series of unforeseen delays, for which we apologize, the CD of Robert Silverman's performance of Beethoven's monumental work for solo piano, the Diabelli Variations (Variations, STPH017-2), is available for purchase from our e-commerce page today, Monday, October 2.

I couldn't resist posting one more photo of Bruce Thigpen's fan-driven infrasonic subwoofer, this time showing the drive-unit in operation. Loaded with an infinite baffle—it is in the next room—it fires into a foam-lined sub-chamber, which low-pass filters the residual fan noise, leaving just the awesome infrasonics to pressurize the room next door. Because the fan is providing the main motive power, just 30W of audio signal was required to create an spl of 115dB at 8Hz!

There are always oases of two-channel audio on the main floor at a CEDIA conference. Boulder Amplifiers were showing their beautiful-looking and equally beautiful-sounding range of solid-state electronics, including their cost-no-object 2000 series components and the more affordable 1000 and 800 series gear. The latter includes the $5k Model 850 200W monoblock (center), seen here framed by company founder Jeff Nelson (left) and marketing exec Rich Maez (right).

Eminent Technology’s Bruce Thigpen has always taken an interesting slant on how to design audio products—his air-bearing tonearm was one of the best-sounding back in the day and his push-pull planar magnetic speakers are thought by some to be unbeatable. But at THE Show, held next door to the official CEDIA venue, the Convention Center, in the Denver Athletic Club, Bruce was showing off his infrasonic subwoofer. Yes, that’s a fan, which rotates at a constant 800rpm. The wrinkle is that the audio signal is used to vary the pitch of the fan blades. Feathered with no signal, when driven with audio the twisting blades produce a massive acoustic wave with very little power input. The bandwidth is limited by the fan speed to below 30Hz or so—you have to rotate it faster to reproduce higher frequencies but then its self noise increases rapidly— but it will reproduce frequencies as low as 1Hz with a very high spl.