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Richard,


Great point to bring up!  You are talking about being mislead by a lissajous pattern (phase scope) or phase torch under these circumstances, right?


Instead the best we can do is to fall back solely on our ears and live spectrogram, trying to establish maximum high frequency response, yes?


-Karl



Karl Fitzke
Audio/Visual Specialist
214 Olin Library
Ithaca, NY 14853

607-255-5521
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________________________________
From: Association for Recorded Sound Discussion List <[log in to unmask]> on behalf of Richard L. Hess <[log in to unmask]>
Sent: Saturday, December 3, 2016 2:44:16 PM
To: [log in to unmask]
Subject: [ARSCLIST] Setting azimuth from program - a caution

I have been digitizing a batch of tapes for a university music program's
archives. Most were made in a the several campus performance spaces, and
from the sound of it and experience, the preponderance of these
recordings were made with spaced hanging cardioid microphones. While
stereo mics were also widely used, these sound like spaced mics.

Anyway...none of the tapes had tones and from time to time there is a
tape with an offset solo instrument. Remembering that we're looking for
fractions of a degree accuracy in adjusting azimuth playback, when we
see two separated mics, all bets are off.

With the speed of sound being about 1100 feet per second, we can see how
moving a mic less than a foot is the length of a complete cycle at 1 kHz.

So, this type of recording is almost impossible to accurately adjust.
While full ensembles work well with the stripchart in StereoTool, a solo
instrument or voice can show a huge azimuth error which is really an
artifact of microphone placement relative to the source.

Cheers,

Richard


--
Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada                             647 479 2800
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.