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.



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