I've been following this thread, and others like it over the years, with
some interest. While only a conjecture, wouldn't it be possible to mount
a small sensing head before the erase head that would track changes in
azimuth as the tape plays and then apply that to a servo driven
mechanism that allows the playback head to compensate? Sounds like it
might be possible if any changes in azimuth are smooth over time. Has
anyone tried it?
I. too, have used a 4-track head to copy 2-track and bi-directional
4-track material, with varying success. Usually there's a high noise
floor, I think because you're only getting 50% or less of the signal off
the tape with the smaller individual head width. Azimuth has to be
adjusted to match that of the original machine, of course.
On 1/6/2012 1:27 AM, Tom Fine wrote:
> Hi George:
> I've done #1 many times and it works as long as the tracks can be
> adjusted into azimuth with each other (not always the case if the
> half track head was way off-azimuth in a manner that the azimuth "bows
> outward" toward the edges). Keep in mind that with high-quality music
> recording, you can hear a different between a track that was actually
> played front-to-back and one that was played in reverse and then
> digitally made front-to-back. Richard Hess will hopefully explain why,
> it has to do with how tape machines deal with attacks and wave fronts.
> The difference shouldn't be drastic, but I find it audible. With
> lower-quality content, it doesn't matter, to my ears.
> I don't recommend #2. Get a full-track head, although that too
> presents problems with warped or badly slit or shrunken tapes. With
> tapes that don't ride well in the transport, I've had good luck using
> a Tascam 4-track quarter-inch machine and using either the least-noisy
> track or, more commonly, the two center tracks, providing I can get
> them to maintain good azimuth.
> -- Tom Fine
> ----- Original Message ----- From: "Gregorio Garcia Karman"
> <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, January 05, 2012 9:53 PM
> Subject: [ARSCLIST] transferring open reel tapes - track formats
> Dear list,
> considering the possibility of the following compromising solutions in
> the digital transfer of open reel tapes...
> 1. playing a mono half-track open reel tape on a stereo machine and
> reversing the channel playing in the wrong direction digitally.
> 2. playing a full-track mono tape on a stereo machine.
> ...what are the considerations that speak against those?
> Thanks for your advice