Re: [AV Media Matters] Print-through

[smolians@erols.com]

I discussed application of a weak magnetic field to reduce
print-through with Del Eilers of 3M.  They published a sheet on
making such a set-up many years ago.  I recall him saying he never
saw one in operation and wondered if it could really be effective
without being destructive.

Exercising the tape is about the best bet.  But beware- if the
problem is caused by serious oversaturation at recording rather than
drift from adjacent layer contact of a normally loud signal, I'm
told this is ineffective.

Spoken word recordings taken in a dry ambience can be a print-through
nightmare.

Steve Smolian

----- Original Message -----
From: "Jim Wheeler" <Jimwheeler@aol.com>
To: <AV-Media-Matters@topica.com>
Sent: Thursday, June 08, 2000 5:41 PM
Subject: [AV Media Matters] Print-through

>The expert on the subject of print-through is Neal Bertram.  Neal was a
>Research Physicist at Ampex and published a 33 page article about
>print-through in the October 1980 issue of The Journal of the Audio
>Engineering Society.  Neal is now the Head of the Center for Magnetic
>Recording Research at U.C. San Diego.
>
>Print-through is caused by "thermal idiots"--magnetic particles
>that didn't
>line up when told to by the field of the recording head.  Thermal
>idiots are
>weak particles so they can have their magnetic dipole
orientation changed
>easily.  One of the Studor machines applies a magnetic field that
>is too weak
>to erase the good guys but powerful enough to neutralize the
>problem dipoles.
> I never liked the idea of a magnetic field near a master tape.
>
>Neal and his research colleges discovered that thermal idiots can
>be returned
>to their random orientation by a mechanical shock.  I joked that
>you should
>drop the reel of tape on a concrete floor but Neal didn't like
>that approach.
> He found that a couple of high-speed passes through a tape
>recorder would
>greatly reduce the print-through.  You should use a machine that
>has several
>turns in the tape path to stress the tape.  I doubt that an
>ATR-100 would be
>of any use since it has such gentle tape-handling.
>
>Jim Wheeler
>
>
>
>
>