I noted the following in reading Robert K. Morrison's excellent "Standard Tape Manual." Some who are
big fans of albums produced on 24-track analog tape decks might find this interesting. Did you know
that 24-track 2" tape has the same track size, 0.043", as quarter-track mass-duped reels, or
quarter-track reels made by "amateurs" at home. Of course most 2" decks run at 15 or 30IPS, so you
get sound-quality boost from the higher speed, but there's no denying it, skinny tracks is skinny
tracks. Another advantage in the 2" format is a larger guard band between tracks, 0.041" vs 0.025"
for quarter-track quarter-inch format, so less crosstalk.
Some comparisons:
Full-track quarter-inch tracks are almost a full quarter-inch wide, 0.234"
Two-track quarter-inch tracks are 0.075" wide with 0.084" guard band
Four-track 1/2" and Eight-track 1" tracks are 0.070" wide with 0.060" guard bands
16-track 2" tracks are 0.070" wide and the guard bands are 0.057" wide
Interestingly, Morrison's book, published in the 70's, had no data for 3-track 1/2" tracks, the
format was totally out of use by then.
Keep in mind that a mono cassette track is 0.060" wide, but moving a much slower speed and generally
using very thin tape.
Obviously, there are plenty of good-sounding recordings that were made on 24-track 2" machines, so
the skinny tracks don't compromise the format in all cases. And I'm not sure how much any of this
matters if you are using tape as compression effect or a harmonic-distortion effect to "warm up the
tracks."
-- Tom Fine
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