Hi Ted, Richard, and friends, thanks for the very specific and kind responses. I realize that occasionally I have come across tapes with a similar high frequency disturbance, concentrated around a single frequency. Unfortunately I haven't been consistently taking notes of the frequency of this tone until now. The FFT has enough bins to say this one is definitely 11100 and not 10000 though.. I would tend to think that your answers suggest this is a tone that interfered in the original recording (this time it was a home made recording made with a microphone). I know I can notch it quite effectively but I was interested to know if this might be a symptom that something could be wrong with the tape and I should be trying to fix it before transferring. Will keep an eye on the FFT display and see if this frequency is consistent in the next tapes with HF disturbance. Huge tanks guys. G On 06.02.2012, at 20:57, Ted Kendall wrote: > On 06/02/2012 17:39, Gregorio Garcia Karman wrote: >>> Subject: Identifying the cause of a squeaking BASF >>> >>> 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] >>> >> PS: I have another tape with a high frequency noise at ca 11100 Hz throughout. Could this be also the effect of sticky shed? >> >> thx > If it's a tone, then it could be 405 TV line frequency (actually 10.125kHz).