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Meeting held November 9, 2011, Microsoft Studios, Redmond, WA.
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Meeting held November 9, 2011, Microsoft Studios, Redmond, WA.
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The PNW Section's November 2011 meeting saw Jonathan Novick, Sales Director for Audio Precision of Beaverton, OR, give his presentation on "Lies, Damn Lies, and specifications."
Jonathan is Sales Director at Audio Precision. He is a past chairman of the LA Section of the AES and has served on the executive committee there for seven years. Jonathan is an active member of the Consumer Electronics Association standards committee on audio and is co-chair of the Product Design track for the 131st AES convention. He also co-chaired the Live Sound tracks for the 129th and 125th AES conventions. Jonathan holds a BSEE degree from Rensselaer Polytechnic Institute and spent much of his professional career involved in the design and simulation of RF and microwave circuitry.
He discussed audio equipment specifications, their use and abuse, standards and regulation, and the correlation of today's tests with audibility. He presented a demo in which he fed music into his distortion box, which then was able to progressively add distortion to the signal. The box contained a number of TL072 op amps, with different circuitry to make different distortions. The audience was asked to close their eyes, and to raise their hands when they heard something other than music. He said he'd stop when about half the audience had their hands up. First was straight ahead clipping, and after enough had raised their hands, he switched the source from music to a sine wave and then measured the distortion. 34% THD+N, which was a bit eye-opening. 2nd was crossover distortion, and that was more audible sooner. 3rd was slew limiting.
Reported by Gary Louie, PNW Section Secretary, and Rick Chinn |