Best Sound at Axpona? By John Atkinson

Transcription

1 AXPONA 2010 Show Report Best Sound at Axpona? By John Atkinson Posted Wed Mar 10, 2010, 4:53 PM ET I had respected more than loved the Legacy speakers I have heard in the past, but without a doubt one of the best two-channel sounds I heard at Axpona was provided by the giant Helix loudspeaker, shown here with Stereophile s Michael Fremer. Front-end at the Show was an Ayon CD player, and the speaker's crossover is implemented in the digital domain using FIR filters and 24-bit DACs and the six channels of amplification were provided by two three-channel McIntosh MC303 amplifiers. The Helix speaker is actually a four-way; there is a rear-facing 15" subwoofer driven by twin ICE- Power class-d modules. The front-facing, openbaffle loaded upper woofers are actually backed up by second units, which, as with a twindiaphragm microphone, gives a cardioid directional pattern, allowing a more optimal match with the room's acoustics than with a conventional omnidirectional bass unit. Completing the drive-unit complement, twin silkdome tweeters are arranged side-by-side and are flanked by four midrange units. Considering what you get, the price of the Helix is a notunreasonable $46,000/system, including the DSP/DAC crossover unit

2 AXPONA Event Coverage Jacksonville, FL Sat March 6, 2010 Coverage and photos by T. Kulavic One highlight of the AXPONA event was an open forum of loudspeaker design strategies and philosophies hosted by Stereophile s John Atkinson. A panel of invited speaker designers from Legacy Audio, YG Acoustics and Audience AV discussed their products and their approach to bringing a product to market. Aktinson opened the discussion with a summary of trade-offs designers must balance to optimize sonic results. These parameters included enclosure size, overall cost, and other practical considerations. The open forum was largely an interaction between Atkinson and Dudleston who were clearly a wealth of knowledge. Dudleston complimented Atkinson on the consistency of his MLS measurements over the years, while Atkinson mentioned he desired a method for measuring imaging quality directly. Dudleston suggested he rely on the ratios of stereo summations between correlated in-phase, and correlated out-of-phase signal at the listener position. Atkinson asked Dudleston to explain the meaning and importance of HRTF, the head related transfer function, and how it relates to imaging. YG s Dick Diamond, host John Atkinson, Legacy s Bill Dudleston and Audience AV s John McDonald.

3 Legacy Audio s chief, Bill Dudleston, explained that the wavelength at 10kHz was about an inch, at 1kHz about a foot, and at 100Hz about ten feet (11.3 ft to be precise). For a loudspeaker to have uniform directivity across the spectrum beginning with a 1 tweeter, it would require a pair of 6 drivers or a 12 in the mids and a massive amount of piston area at the bottom. Dudleston also noted that efficiency of loudspeakers in general was lacking (typically below 2%). His strategy of increasing radiating area increases efficiency and dynamic range, while dramatically lowering distortion, stored energy, and decreasing settling time. The trade-off Legacy requires is a larger baffle or enclosure. Atkinson remarked about the detailed cabinetry and the application of digital signal processing within the Legacy line. A staff member from AudiogoN filmed the event, hopefully to be viewed on YouTube soon Legacy Focus SE, an Ayon Triton integrated amp, and a Ayon CD-2 CD player.. The fourth display had both the big cherry Legacy Whisper HD and the smaller black Focus SEs.

4 The Ayon CD-5 again served as CD player and preamplifier driving a pair of massive Ayon Orthos monoblocks ($20,500). The eight KT88s run in both triode and pentode generating 120 watts and 300 watts respectively. The final setup featured the Legacy Classic speakers with an Ayon Orion integrated amp ($2,399) and an Ayon CD-07 CD player. The Orion integrated uses four KT88s and produces a power output of 30 watts/channel in triode mode or 50 watts/channel in pentode mode

5 Chuck Bruce (Atlanta Audio Society), Michael Fremer (Stereophile) and Bill Leebens (AudiogoN) stop by to listen to a wide range of tunes on the Whisper HD speakers.