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----- Original Message ----- 
From: "Richard L. Hess" <[log in to unmask]>
> Here is the application:  I have a bunch of two-track mono tapes that
> need to be digitized (29 to be precise). They are oral histories.
> Both sides were recorded with the same recorder (as it turns out, the
> entire batch appeared to be recorded with the same recorder with the
> azimuth out the same amount on all tapes).
>
> So, rewinding the tape and playing it through gives me a nice play
> wind and both sides transferred in one pass. BUT it leaves me with
> the first side reversed end-for-end. In other words, playing backwards.
>
> Using an 8-channel 44.1/24 card (these were recorded at 1.88 in/s) I
> can ingest four tape machines simultaneously. I used four Sony
> APR-5000s. One tape was 3.75 in/s in the last batch, so I did that on
> the Studer A810 NAB 2-track since the APR-5000 I had it on wasn't set
> up for 3.75 with the slow-speed NAB head stack (slow speed 3.75 to 15
> rather than 7.5 to 30 in/s). I get the APRs to do 1.88 in/s by using
> -50% varispeed and a specially aligned register (there are three
> alignments per speed for each of 12 heads for each of three speeds,
> or 108 memory locations per machine)
>
> Since no noise processing was involved, it doesn't hurt a thing.
>
> Also, since it was recorded on the same machine, although it's
> counter-intuitive, draw it out...you'll find that the azimuth error
> for one side ends up being the same for the other and you get
> correction when played backwards. It's not 2x worse.
>
> So, I had 28 files and reversing them takes about 5-10 minutes (24
> bit 44.1, 90 minutes each) Not something you want to sit and do
> manually when you can do it in a batch.
>
> I feel good about buying a Canadian product to do this, although my
> primary editor, Samplitude from Magix, comes out of Germany as do the
> Algorithmix plug-ins I use for various cleanups. I'm not sure
> GoldWave will see a lot of use, but it will be fun to experiment with
> their filters and other batch things. Although with Samplitude, there
> is no latency to apply almost any effect (reversing is one that
> doesn't follow this rule) as most effects are done real time.
>
> The average file I have to reverse is about 750 MB mono.
>
> I know...more than you wanted to know, but the key do doing this is
> reliable, QC-able, but fast workflow. I have had my fill of
> simulating being at a party and listening to four conversations from
> four different speakers for a while. I didn't see (in the waveforms)
> nor hear any major head clogs--although 1.88 in/s is not very
> high-frequency rich in reel recordings. The 3.75 one was a breath of fresh
air.
>
Okeh...I THINK I see this...except for one detail! Are you playing
the tapes as though they were two-track stereo (each half of the tape
is a different channel, with one being reversed...)? If so, do you
digitize the "backwards" signal and then digitally reverse it?
So you are looking for a sound-file application that can reverse
a "backwards" (or, for that matter, any) sound file?

This leads to a couple of related thoughts...

1) Perhaps such an application could be packaged as "Is Paul REALLY
Dead.exe"...?! There might be a demand among Beatles aficianados...

2) At the same time, I can't help but wonder what the results would
be if other digital files could be reversed and run (other than about
about a gazillion "Illegal Operation" crashes...)

Steven C. Barr