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Re: [ARSCLIST] Information on open reel players and tapes

----- Original Message -----
From: "Jay Gaidmore" <JGaidmore@xxxxxxxxxxxxx>
> Could somebody lead me in the right direction to finding out more about
> reel to reel players and tapes?  I am looking for information that will
> help me understand the differences between 1/4 track, 1/2 track, and
> full track, full-track mono, 2-track mono and stereo, 2 track-mono, full
> track head and two track head.
> If a reel to reel player is described as 1/4" broadcast 2-track, what
> does 2-track mean, as well as 1-track, 3 track, and 4-track?  In a
> 4-channel, 1/4" machine, to what does the 4-channel refer?  How about 2
> and 3 channel?
Dunno if this has been answered...but I can answer this part:
Generally, audio tape is divided into parallel "tracks" thusly:
top edge of tape
bottom edge of tape

For a momophonic (1 channel) signal, only two tracks (in some cases,
1 track) is needed. This is usually set up so the top half of the tape
is recorded in one direction, then the tape is reversed and the bottom
half is recorded in the opposite direction. This doubles the playing
time of a given length of tape. For a stereophonic tape (see diagram
above) two tracks are laid down in each direction, since there are
two channels each with a different signal. Cassettes also use this
system...since cassette tape is 1/8" wide, each track is 1/16" wide.
An "8-track" cartridge has exactly that many tracks; since the
stereo signal requires two tracks, four different pairs of tracks
are available, and the playing heads shift slightly for each pass
of the continuous-loop tape to play each of the four segments of
the recorded material.

Professional machines, using wider tape (up to at least 2") can
record many more separate tracks (or pairs of tracks for stereo)...
up to at least 64 tracks (32 pairs). Usually, these are recorded
in such a way that playing all the tracks simultaneously would
result in the recorded song(s) being played; the "mix" refers to
selecting the levels for each of the 32 stereo signals so the
final combination sounds as the engineer desires it to (each
instrument or vocal usually is recorded to a different channel
or pair of tracks). The engineer, of course, has to keep track
of which signal is on which channel, so he/she/it knows which
knob to turn to raise or lower the lavel of, say, the bass guitar.

However, it is possible, by some judicious fiddling with knobs,
to put entirely separate mono signals on a pair of stereo tracks
using a home-use reel-to-reel tape recorder. I have a number of
reel-to-reel tapes done this way of items from my 78 collection;
turn the level on one channel to zero while taping 78's on the
other channel for the first and second passes (one each direction)
and then feed  the input into the unused channel for the third
and fourth passes.

Note that it is possible to record an odd number of tracks...but
not very useful (except for one track, which is how the earliest
tape machines worked). You could either design heads of a special
width to record one third (or 1/5 or 1/7, etc.) of the tape, or
use an even number of tracks and not record one. However, this
means you would get an odd number of playing passes, so the
tape would at the end have to be rewound without playing, so
it would be ready for playing later.
> I have seen many references to setting the correct azimuth.  What is
> this and how do you set it correctly?
This one I can't answer!
> As you can see I am very much a novice trying to learn.  References to
> website or publications that would help answer the questions above would
> be greatly appreciated.
Hope the above helps...
Steven C. Barr

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