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Old 11-17-2016, 07:20 AM
Musicat Musicat is offline
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Join Date: Oct 1999
Location: Sturgeon Bay, WI USA
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Originally Posted by Fenshaw View Post
I was doing a lot of recording in those days. Almost all of the reel to reel recorders had two speeds, 7.5 inches per second (IPS) and 3.25 IPS. If you were recording voice, or something low fidelity you would use 3.25 to save expensive tape. If you wanted higher quality you used 7.5. There were even machines in the high end with a 15 IPS setting when price was no object. I had a court reporter's recorder that had a 1.75 IPS so the reporter wouldn't have to change tape during a long session.
Nitpick: Your speeds are a little off. Here are the common tape speeds; each is half of the previous:

30 IPS
7.5 (7 1/2)
3.75 (3 3/4)
1.875 (1 7/8)

Note that professional recorders had an adjustable speed feature (VSO) and were not limited to these fixed speeds. I think (but I'm not sure) at least one Ampex had a way to speed up or slow down by musical half-steps so the engineer didn't have to guess or calibrate.