[BC] Article in RW Workbench--Question?

[Steve Lewis]

'Scuse me, Tom...

As I understand your explanation below, this method would only work if the
recording were made at the proper 1 7/8's IPS but allowed speed adjustment
during playback.  If the recording took place at some other speed, that
other speed would be required to play it back properly.

-----O'rig Msg-----

OK. Let's assume I have a cassette deck with an unknown
speed adjustment. I set up an oscillator with 1000 Hz. The
oscillator feeds the cassette input and channel one of the
dual trace scope. The scope syncs to channel one. Channel
two is fed from the cassette deck audio output. We record
about 30 seconds of the tone. Now we play back what we
just recorded. Ideally the frequency will read 1000 Hz. If not,
we adjust the speed control for 1000 Hz by observing the
dual trace waveforms sync up.

I just performed this procedure on a two slot deck. It is a
Teac W-780R. I used a Tektronix 2236 scope with built-in
freq counter. We do NOT really care what the exact freq is,
as long as it is stable. We are comparing what we recorded
to the input signal. If the speed were wrong, the playback
freq would be higher or lower than 1000 Hz, or whatever we
freq we initially recorded.

Tom Osenkowsky, CPBE