From: bill@bilver.uucp (Bill Vermillion)
Subject: Re: Help!
Organization: W. J. Vermillion - Winter Park, FL
Date: Sun, 22 Nov 1992 17:31:45 GMT

In article <19485@ucdavis.ucdavis.edu> matthews@eecs.ucdavis.edu (Thomas W. Matthews) writes:
>Didn't the 8-track evolve from the broadcast audio cart?

No - they are two entriely different mechanisms.

>I thought a guy named Muntz (who was perhaps the first
>audio/video guy to proclaim himself insane during his
>commercials) adapted the broadcast audio cart to 
>four-track car stereo (two stereo programs).  Then a guy
>named Bill Lear (of Lear Jet fame) came up with the eight-track.

True.

The 4-track used the Fidelipac cartridges that were used in
automated music systems, that were then used in the broadcast
industrty.

It's going to be Vermillion's trivia and nostalgia time again
so here we go.

Until the late '50s radio/tv stations broadcast their audio
commercials from reel-reel tape or from discs.   Many stations
still had such things as the RCA 7B lathe for cutting discs
locally.

Discs were used because they were easy to file and quick to cue
up.  Tape was recyleable and did not wear.  But it was a pain
to keep track of the reels and cue them properly.   Woops - I
meant to cue to the 6th cut on that tape and not the 5th !!!

Gawd - I do remember those days - because I was doing it.

There had to be a solution.   And there were 3 solutions.  Two
that were uniquely developed for broadcast and one that took
existing technology.

One of the two unique products was a complete breakaway from
any existing technolgy.

It was the Gates Spotmaster.  It held 101 commercials that were
up to 90 seconds in length.  Access time to any one commercial
was as quick as the dj/engineers hand could move, and for the
next commercial - about 10 seconds - for a total rewind of the
tape.

This was quite a piece of equipment.  It used ONE roll of tape,
that was 90 seconds long in play time (I do not know what the
tape speed was) and 101 tracks wide.  This reel of tape was 13
INCHES wide.

There was a slot on the front with 101 sub-slots.  You just
moved the selector lever to the number you wanted and it
positioned the tape head over that track.

Hit play, and away you went.

Another unique it was the device from RCA that used "magentic"
45 rpm records.  I never saw one in real life.

It used the existing RCA 78/45/33 broadcast turntables.   

The record/playback media was a magnetic hardrubber disk the
same size as a 45 rpm record.  The disc was grooved - and had
about 1 minutes worth of time at 45 rpm.

The record head was mounted in a standard type transcription
tone arm and was the width and size of the groove - sort of
like an oversized stylus.

This used a lot of existing technology - but a propiertary
interchangeable medium.  The Gates unit used a 13" tape, but
you could not change it - you were limited to 101 spots.

Then came the broadcast cart.  I beleive it was Collins who
brought those out the first.   I was more intimately familiar
with the RCA units that followed - having repaired them often.

These units used the existing Fidelipac cartridges.  These were
continuous loop cartridges in 5, 15 and 30 minute lengths when
run at 7.5 ips.

There was a thin graphite lubricated tape in a continous loop.
The tape pulled from the center and wrapped on the outside.
Since the outside radius of the tape loop was larger than the
inside where you pulled it from, the rotating platform that the
tape rode upon tried to wind in tape faster than you played it
out.   

That is why you needed graphite backed tape - so it would
slide.  If you got the loop too tight when loading these you
would immediately cause the tape to seize. (carpe tapium?)

These tapes were used for background music before they were
used in broadcast.

A typical device was a Pentron tape recorder. (Remember that
name?).   The tape was placed on the machine - which had it's
pinch roller exposed and the play button was pushed.

These were 2 hour tapes.  They ran at 3.75 ips on the large
cartridge.  But these used tape that had oxide on both sides
and the tapes were spliced into a mobius loop to double the
play time.

The Fidelipac cartridges had only the tape, the tape turntable,
and pressure pads.  There was a hole in the bottom of the tape
that the capstan swung up through.

You pushed the tape in, engaged a lever that swung up the pinch
roller arm assembly and locked it in place.  To take it out,
you had to press a lever to release it.

This made for a rather complex and heavy mechanism.  Remember
this technology was designed for industrial use - and the
mechanism was quite rugged.  I don't know about the Collins but
the RCA's used the Viking tape transport (ah - another name out
of the far distant past!)

This made the units heavy and expensive.

Lear's 8-track put the pinch-roller inside the cartridge.  This
meant you could insert and remove with no other moving parts.
The capstan and the tape-head track-shifting mechanism were the
only moving parts.   I seem to remember that one/some of the
cartridge devices used used multiple play head sections and did
not shift the head.  (Hey - this is from memory of about 25
years ago and I never owned an eight-track or 4-track car
player - so forgive any mis-rememberances - please).

The 8-track design was much simpler and much more cost
effective as a consumer based medium.

So that's it for this shot at "Tivia in Review" :-)

Last week's correct answer to what musical instrument is the
decendant of the sackbut, are Dick Pierce, and Ian McVey,(who
replied by mail) along with the poster to the net.  The
instrument is the trombone.  You all now have your rec.audio
subscription extended for another 10 years!

Not that this is going to be a regular feature, but how about
this piece of trivia.   Who is the maker of a microphone that
you stick up your nose, and for additional credit, what is it
used for?

(Gawd - I hope 'I' rember that one correctly)

Bill
-- 
Bill Vermillion - bill@bilver.oau.org  bill.vermillion@oau.org
                - bill@bilver.uucp 
                - ..!{peora|tous|tarpit}!bilver!bill