Recording - February 2015 - 64

By Scott Dorsey
Now and then, you may run across old hand; if you are starting with a cassette that and adjust it back to its nominal position.
cassettes that need to be transformed into is held together with glue instead of screws, With most consumer machines, there are
some format useful in the modern digital it can be an adventure to get it open. (A only a limited number of times that you can
world. These days, people forget just how Dremel Moto-Tool helps.) See Figure 1.
do this before you wear out the screw
bad cassettes can sound-how they gave
So let's assume that you've managed to threads, but that's fine if you're only doing
a bad reputation to the words "analog get the tape in a good shell and you have a tape rescue now and then. There were
recording" for a few years during the it in as good condition as you can. When some machines made with vernier azimuth
beginnings of the digital transition. On you put it in your tape machine and play control for playback of old tapes, but most
the other hand, people may not realize it back, you have to deal with the next of them came off the market when the
that with a little bit of work it's possible to problem: azimuth adjustment.
Dragons appeared. They still turn up occaget workable sound out of cassettes.
The most severe problem with moving sionally, though.
In the analog world, media degrade with tape past heads properly is keeping the
The technique is to listen in mono, not
every generation of copying... sometimes tape completely perpendicular to the stereo. Sum both channels to mono, and
severely, if one of several mistakes
adjust the head azimuth screw
I'll mention below happens in the
for the best high-frequency
copying process. Therefore, the
response. Having an FFT display
absolute number one most imporon a DAW can make this easier,
tant thing you can do to improve
but you can do it by ear.
sound quality is to get back to the
If you were listening in stereo,
original generation, or as close as
you'd hear the stereo image
possible to the original generation.
moving from side to side as you
If at all possible, get the original.
turned that screw, advancing or
But maybe you have a predelaying one channel with
recorded mass-duplicated tape
respect to the other. You'd also
that you bought in Cambodia, of
hear comb filtering in each chana local band that's so obscure Figure 1: Cassette shells held together with screws (left) nel, but it wouldn't be as severe
you can't even find any reference are much easier to work with than shells held together as the comb filtering you'd hear
to it on the Internet. Or maybe with glue (right).
in mono. Putting playback in
you have a copy of a copy of a
mono exaggerates the comb filrecording of your father from when he heads, both in recording (which you tering because you're listening to a wider
was 12, and the master was flushed don't have control over) and in playback area of the tape, and listening for that (or
down the toilet by your uncle when he (which you can control on reel decks but seeing it on the FFT) is the easiest way to
was 6. If that's all you have, that's what often can't on cassette players). If the make sure it's correct. See Figure 2.
you work with.
original recording was made without the
Once you have set the right azimuth for the
tape completely perpendicular, or it was tape, play it back and record it into your
Step one: proper playback
recorded in one shell but transplated into DAW. If possible, turn the Dolby noise reducThe first part of the rescue process is to another shell with slightly different geom- tion off first; we'll talk about that in a moment.
play back the tape, and as Dale etry, then we say it has azimuth error.
Now, there is software out there that
Manquen says, the most important thing You'll need to adjust the azimuth angle on claims to do "azimuth correction" after the
that a tape recorder does is move tape the tape head mount to compensate for it. fact, which adjusts the two channels to cenpast the heads. It needs to do it cleanly,
If you have a Nakamichi Dragon tape ter the stereo image. That software, though,
with accuracy and stability... and, sad to machine, it will automatically compensate is only looking at the two channels individusay, cassettes are not known for this.
for azimuth errors. If you have a million ally, not each part of each track, so it canOne of the amazing things about the cas- cassettes to transcribe, get a Dragon-or not eliminate the comb filtering that is heard
sette is that most of the tape transport is contract out the rescue job to somebody in stereo. Get the transcription correct rather
inside the cassette cartridge. The bad part who already has one.
than relying on bandages after the fact to try
is that if the cassette itself is damaged, you
If you don't have a Dragon, you're and compensate for transcription errors.
get tapes that squeal or pop or flutter. going to have to find the azimuth screw or
If you have a second generation tape
When this happens, the tape itself needs to nut, adjust it for each tape you're rescuing, instead of the master, you can't really
be taken out and transplanted into a new and then afterward put on a standard tape compensate for the azimuth errors on the
shell that does not squeal or rattle. This isn't (one that was originally recorded on that first dub, but you can only do what you
too difficult a task, but it requires a steady deck before you messed with the azimuth) can do. Have courage!
64

RECORDING February 2015

Recording - February 2015

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