> Do you know what results were discovered from this monitoring?
Yes, and it did not paint a pretty picture.
> I always figured azimuth drifts quite a bit in the typical cassette, just due to mechanical issues.
> Did that turn out to be true?
Absolutely. A challenge of that time was to design a tape transport
that would isolate the loop from most of the cassette shell guidance
influences. The best of the servoed twin-capstan designs attained
this, to some extent.
> Were certain types of cassettes better at maintaining azimuth throughout the tape pack vs. others?
Yes, but the precision ones were almost never employed, due to vastly
Recall that in 1984 everyone was still marveling at the miracle of the
Compact Disc. The Philips Compact Cassette only had another nail
driven into its coffin when its azimuth issues were closely examined.
Grass Valley, California