I agree with you. Another way of looking at that is that the squeal
induced by either SSS or generic Soft Binder Syndrome (SBS) (SSS is a
special case of SBS that sheds a lot AND responds to baking by
definition), the squeal is caused by stick slip. It is NOT a tone, but
the tape rapidly starting and stopping.
If there was silence, the noise would be less audible in the recording.
The squeal frequency-modulates the playback signal and that frequency
modulation is random and cannot be easily (if at all) separated from the
DC offset and bias may contribute to audible squeal during quiet
portions of the program.
11,100 Hz is an odd frequency in my experience. Here in North America
(NTSC, 60 Hz power, 525 lines, 29.97 fps), we have 15,734 Hz which is
the line rate of NTSC colour video. The comparable signal in a PAL
environment (50 Hz power, 625 lines, 25 fps) should be 15,625 Hz. So
that does not explain 11,100 Hz. Most tape machine capstan reference
signals that I am aware of are 800, 1600, 3200, 9600, or 19,200 Hz.
I do not believe that 11,100 Hz was ever used for film sync, but there
is an excellent document explaining those systems if you wish to check
(I convinced the EBU to bring it back from hiding in the archives
several years ago). EBU T3095 (1973) film sync systems:
A quick scan of that document shows signals at 14 kHz and then a few
obsolete systems in mid-band (400 - 3000 Hz) but the most widely used
systems recorded mains-frequency-like signals in a way that would not be
picked up by the audio head.
So, we are at a loss as to what the 11,100 Hz tone is (at the moment).
One thought might be that the tape was copied on standard recorders at 8
X original speed and the frequency is the bias of the recorder which was
really 88,800 Hz (~90 kHz) at the time. That is in the range of possible
bias frequencies for early recorders:
On 2012-02-06 1:11 PM, [log in to unmask] wrote:
> In my experience, tape with SSS squeals, first softly and possibly
> intermittently, then progressively louder, causing easily apparent
> distortion as it squeals. Not so much a noise as bad distortion.
> You might also run the tape thru 2 of your fingers. If it is severe
> enough, you can easily feel the stickiness.
> If you only hear the noise on the recording and not coming from the
> machine itself (like mechanical noise) it is possible the tape was
> dubbed from a source suffering from SSS.
> If you are hearing a noise, like a steady state noise, I might suggest
> it is something else.
> What is the source of the original? was it a live performance in a
> room with loud fluorescent lights?
> Pinning it down to a specific frequency like 11,100 doesn't seem like
> SSS to me.
> joe salerno
> On 2/6/2012 11:26 AM, Gregorio Garcia Karman wrote:
>> Is there a reliable way to identify if the high frequency squeaking
>> in the reproduced audio is caused by sticky shed syndrome or other
>> kinds of degradation or it was rather in the original recording? Can
>> squeaking be identified to have e.g. a specific frequency?
>> The squeaky tape has a backcoat: BASF LGS 26477
>> It does not seem to shed any deposit on pinches aor heads, so I am
>> unsure if it would be advisable to try to bake.
>> Thanks and best regards
>> Gregorio Garcia Karman
>> [log in to unmask]
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Quality tape transfers -- even from hard-to-play tapes.