Multi Track Cassette Tapes

[snicklin]

This may be the shortest post ever, but there is something that I would like to know, just for knowledge as I have no plans to do any work in this area... but it may be of use to someone else years in the future....

 

... ok, I would like to know how the multi-track tapes are produced. By this, I am referring to those which have a song/speech playing and then data is loading.

 

Is it as simple as that you have a recording of the speech/song and then you record the program over the top? If it is that simple, just reply 'yes'. If not, please expand... thank you.

[Rybags]

I don't think it's that simple... the r/w head AFAIK only writes to the data track but the problem is the erase head does both tracks.

 

Simple way to test, just get a music tape you know has both tracks in use then save a program over it - there should be no audio left once that's done.

 

In the day, bulk production would have been by hardware which just mass duplicates off a master tape. Production of the master tape would have no doubt been a case of produce the data portion with Atari hardware then produce the master with combined audio/data with (non Atari) production gear.

 

In the modern day, we could use numerous techniques to produce a combined tape. The best way would probably be to use a utility like CAS2WAV to produce the data track, then combine that with your audio into a stereo WAV file.

Then write that WAV file to a CD or DVD and use it as your master to produce a tape with conventional stereo gear.

Or, just play back your master audio file with a stereo tape deck hooked up to the computer.

Edited August 1, 2015 by Rybags

[Andromeda Stardust]

Don't cassettes actually have 4 tracks? Left and right stereo side A and left and right stereo side B. An auto reverse head could in theory be rewired to read/write all four tracks simultaneously.

[+CharlieChaplin]

Well,

 

I can simply use my (Hifi) Tapedeck and set the balance to full left or full right, thus recording only the left or only the right channel. But I am not sure about the erase head... will have to try it.

[pirx]

In Mirage we had indeed a small, portable machine copying a master tape to 3 copies both sides in one go. Unfortunately when the master head went bad repairing costs proved to be prohibitive and production was done on octopuss of XC12s.

[tschak909]

In the old days, you'd use a multi-track tape recorder. Any two-track tape recorder (typically used for mastering) would do. You would record the two tracks at separate times, and then ship that tape off to the dupe house.

 

The dupe house would then create what they called a "bin loop", which is, quite literally a large loop of tape, containing the contents of the original master, and use that to simultaneously feed a series of cassette recorders. The process sits on a loop as the end of the loop is reached (typically signaled by a foil leader which trips a sensor), this would cause either a signal to the tape operators to switch tapes, or in the case of larger duplication operations, to eject the tapes and feed new ones automatically.

 

These days, I would just use Audacity to record in the tape data (or in the case of Eduencode, to use its raw output), as one track, set to the Right channel, and drop in the voiceover waveform as the left channel. The resulting audio can then be played out of a soundcard to a cassette. Since Cassette tapes have a signal to noise ratio roughly equivalent to 6 or 7 bits in most cases (the best ones can barely top 9, think Nakamichi Dragon.), your soundcard output doesn't have to be spectacular.

 

-Thom

[Mathy]

Hello Pirx

 

... production was done on octopus of XC12s.

 

Could you explain that in more detail please?

 

Sincerely

 

Mathy

Edited August 1, 2015 by Mathy

[pirx]

Hey!

 

A bunch (do not remember the exact number, but possibly 6 or 8 as it is a round number) of XC12 recorders fastened to a plywood, all cables soldered to a PCB with a power supply, an amplifier and/or multiplexer of sorts (custom made), this contraption connected to an 8-bitter with a disk to tape copy software.

You would press record in all the recorders and then start saving.

[tschak909]

http://www.audiodups.com/manufacturing_process.htm<-- that shows a row of Bin Loop recorders.

 

-Thom