\"Granma\" Dave Schein II, CSO wrote:
I am converting a 3" 1/4" 4-track reel-tape to CD. Trouble is, the
beginning is playing back fast and high-pitched (hand-in-hand), but the tail
is slow and low-pitched. This implies to me it is a section from a larger
reel of tape, but on a small reel. I am currently capturing at 3.75ips.

No, you have a tape that was made on one of the Japanese 3" recorders
that drove the reel at constant speed rather than using a capstan. These
were popular for dictation applications in the early seventies. The speed
is not constant; the rate of rotation of the take-up reel is. These things
have a lot of flutter but that was fine for the application. Most of them
are half-track.

Is there a way of balancing out the speed errors?

Yes, you can use a piece of equipment that I designed and used to sell,
which connects to the varispeed input on the ATR-100 and allows you to
ramp speed up or down in a controlled fashion.

Or you can try and find one of the Concord or Sony recorders that the
tape was recorded on.

I tried using a small-spool reel for takeup, but to no avail.

Right.

Should I try transferring the tape to a larger spool, to simulate the
suppossed former reel, or am I way off on that one? My thought about that
is that it may have been from a larger, 7.5ips reel

No, the reel size will not change the speed. On a conventional tape
machine, the tape is driven at constant speed by a capstan and so the
tape speed is independant of reel size.

Any ideas?

Easiest thing might be to write some code to do this in software once
you have acquired the signal. Do your playback with the NAB EQ bypassed,
do the varispeed in software, then equalize it in software again.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."