Thanks for the referral...
There are many different causes for what Henry might be hearing. From
his original posting, I would say that print-through is less likely than
other causes, but it certainly is a point worth considering.
Let's look at some of the issues:
(a) Partial erasure--this is the worst in many ways as it can be totally
unrecoverable. Partial erasure would occur if the erase head were
disconnected or the erase circuitry was not putting out enough energy to
fully erase the tape. That means that the two programs (original,
unwanted AND new, wanted) are now completely mixed in the magnetic media.
(b) Sloppy re-use of pre-recorded tape. Assuming everything is working
fine, but you are using pre-recorded tape and starting and stopping
recording, it is possible to leave gaps of the previous, unwanted
program between start cycles of the new, desired recording. This is what
at least some of the issues that Henry was describing sound like. Unless
these are long and intelligible (from a content perspective) in their
own right, I usually ignore them.
(c) Track incompatibility between original and subsequent recording.
Take, for example, a two-track stereo tape that has been recorded over
with a quarter-track stereo recorder. Depending on the width and
alignment of the quarter-track erase heads, there can still be narrow
strips of perfect-condition original underlying recording existing on
the tape. Here is where my 4-channel, 8-track custom made "elevator"
head which retains azimuth as I scan any 17 mil segment of a tape comes
in handy. This can also be the result of recording over a full-track
tape with two-track or quarter-track new recordings. It is interesting
to note that the Woelke two-track erase heads supplied by Studer and
Sony on pro machines had no gap and erased the full-width of the tape.
The erase heads for timecode machines, on the other hand, did not erase
the tiny centre timecode track, leaving that function to an erase
section of the timecode head. If a two-track tape was partially erased
by making a quarter-track recording over it, and the tape was played on
a two-track machine, one might think that the two tracks are
overlapping, but using a narrower head (quarter track would be fine for
the later program, a special head is generally needed for recovering the
two-track recording) can recover some of the original recording.
Recording on both sides in quarter-track stereo would likely leave only
very narrow bands (if anything) of the original FT or 2T recording. But,
it's imortant that (c) is not confused with (a).
(d) An oddity worth mentioning here is the oddball track 1-2 / 4-3
two-sided stereo tapes I ran across in the collection of the late Leslie
Huggett. On initial playback they appeared to be two-track mono tapes,
but something didn't feel right about the azimuth setting (by ear), so I
developed them and found them to be 1-2/4-3 stereo recordings (instead
of the almost universally used 1-3/4-2 recording system. In other words,
these were reel tapes using the standards later adopted by cassettes for
stereo. The guard band was definitely visible and of course the two
inner tracks were inside the normal NAB two-track head footprint.
The track configurations and erase head configurations are shown here:
A couple of examples of using the magnetic viewer are here:
(shows a quarter-track tape)
(shows a 2-track tape damaged by a malfunctioning quarter-track
recorder's left channel)
On 2013-02-25 11:51 AM, John Spencer wrote:
> Just a thought, perhaps you are hearing either "print-through", or the re-used tapes were not de-maganitized enough to remove the original content.
> While I don't consider wikipedia the de-facto standard for all things technical, there is an article here:
> I'm only guessing, but Richard Hess might have some information on his site as well:
> If what you are hearing is somewhat similar to what you are hearing on the tape, it's probably print-through. If it is completely different material, my guess as I said earlier that the tapes weren't properly erased before they were re-used.
> I'm not the resident expert on this by any means, hopefully others can help you with some tricks once you have them in the digital domain, but I've seen both circumstances. There is no easy fix unfortunately...
> John Spencer ⎮ BMSChace
> [log in to unmask]
> 615.385.1251 phone
> 615.385.0153 fax
> 615.714.1199 mobile
> On Feb 25, 2013, at 9:52 AM, Henry Borchers wrote:
>> As I've explained in this list before, I'm currently working with digitizing a number of amateur 1/4" reels from a student radio archive. Since much of the content produced is amateurly engineered, all too often the stock was reused tape. Along with this practice, one finds artifact fragments from previous generation recordings that run for anywhere between a couple seconds to a few minutes. I am wondering if there is a proper name for these fragments. Internally, I have been using the word "ghosts" to describe these fragments but I was wondering if there was a more established name.
>> Henry Borchers
>> Broadcast Media Digitization Librarian
>> University of Maryland
>> B0221D McKeldin Library
>> College Park, MD 20742
>> (301) 405-0725
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada 647 479 2800
Quality tape transfers -- even from hard-to-play tapes.