Hello, Josh,

You are working with what is called "print through" and has been the 
scourge of tape recording from the beginning.

Technically, there are magnetic domains that are easily flipped. The 
magnetism from the adjoining layer and perhaps a bias field (including 
the earth's magnetism) might have encouraged these easily-flipped 
domains to line up with the magnetic field from the underlying or 
overlying layers of tape. In either case, the field has to go through 
one layer of tape to cause this to happen.

Some very loud "bangs" have been known to print through several layers 
of tape on the reel.

Storing tape tails out tends to bias the print-through process to be 
post-echo more than pre-echo, or so the theory goes and winding tapes 
back and forth a few times may also assist in reducing the print through.

Some have suggested winding the tape in B-wind (oxide out) and leaving 
it for a while, I have not tried this.

Not for the faint of heart, some success has been reported using 
permanent magnet partial erasure OF THE TAPE by a device you place 
against that tape as you wind it. This was made in the 50s or 60s by a 
tape manufacturer and I believe it came in two strengths. There was an 
Audio Engineering Society paper or preprint on it that I recall seeing 
years ago. You may search at aes.org in the library. "print through" is 
a good keyword, I would think.

Finally, some versions of the Studer A820 incorporated controlled 
erasure called "skimming". I have never used it, but it works on the 
same principal, but uses the AC bias (high frequency) signal to do the 
partial erasure.

So we're looking at randomly orienting the particles that were easily 
reoriented in storage to mirror the adjacent layers of tape.

Obviously, any of the intentional partial-erasure techniques, if 
over-applied, could have devastating effects to the recording.

Good luck with this.

Cheers,

Richard



On 2013-10-23 2:02 PM, Josh May wrote:
> Hello ARSC,
>
> I'm new to the list, so please excuse me if this request is out of line.
>
> I'll get right to the crux: I'm working on a digital transfer from a 40
> year old 1/2" master audio tape. The recording is unaccompanied singing,
> and in the transfer I've noticed a very faint bleed-through / pre-echo that
> peaks at about -36 dB. The bleed-through is only minimally noticeable in
> the silence before or after a very loud note, but due to the dynamic nature
> of the recording, I've had trouble making a gate work and sound natural.
>
> So my question is, how could I correct or minimize this problem without
> affecting the original recording, if at all? I'm hoping there are some
> tricks out there I'm not familiar with.
>
> Thanks in advance for any and all help!
>
> Josh May
> June Appal Recordings
>
Richard L. Hess                   email: [log in to unmask] Aurora, 
Ontario, Canada                             647 479 2800 
http://www.richardhess.com/tape/contact.htm Quality tape transfers -- 
even from hard-to-play tapes.