The fact that the decks have stopped themselves on some of these makes it OBVIOUS that these tapes suffer from Sticky Shed Syndrome. If you continue to play these tapes while they squeal you will probably mechanically record the squeal onto the tape due to the actual movement of the oxide particles on the tape. And by the way, you are another of those on the list who have set your email program to have our replies sent to only you instead of the list. Please change this. Mike Biel [log in to unmask] -------- Original Message -------- Subject: [ARSCLIST] Squealing Audio Cassette Tapes From: Karl Fitzke <[log in to unmask]> Date: Wed, February 20, 2013 1:20 pm To: [log in to unmask] Greetings, and thanks right away for your interest and potential help with the following: We have a set of approximately 30 SKC Brand, GX and LX model, Type I cassette tapes on hand to transfer. They are 60 minute tapes. The original field recordist is from New Zealand, where these tapes were recorded. A number of the tapes start squealing after five to twenty minutes of play, and this happens on at least three different Nak CR-7A machines (dual capstan). The squeal is a rather constant tone in amplitude and frequency (2 kHz or so is a guess). The decks have even stopped themselves in some instances. The squealing in some instances has stopped when I stopped the deck, remove the cassette from it for inspection, replaced, and played again. But, only to likely start again a little later. Tapes have been fast forwarded and rewound before being played. I believe the squealing has happened when the tape is packed even better, e.g. after a play on one side (which didn't have noticeable issues). But play of the first side may not have been monitored very closely by personnel, so don't give that all too much weight. I've occasionally seen conical wrapping at the outside of the pack (the outside 1/8" or so, thinking radially). I've transferred some of these tapes to new Maxell shells, removed friction sheets in the original shells, removed pressure pads in the original shells, loosened case screws in both shells, threaded tape on the inside (instead of outside) of the posts near the cassette shell rollers in the Maxell shell. I checked W/F specs on all machines. They are okay, or just out of spec, which does not concern me here (yet). The best I've done is maybe reduced the amplitude and regularity of the squealing with playback of one tape I recall, but I haven't gotten rid of it. My current belief is that we have lubricant issues, and I'm off to read/reread everything I can find in old emails from Richard Hess, Marie O'Connell, Steve Smolian that I saved for future reference, like the ones I've forwarded below. I'd be happy to hear anything else someone may have to offer. Even moral support! ;-D Thanks again for your interest. Best wishes, Karl F. -- Karl Fitzke Audio Engineer Macaulay Library Cornell Lab of Ornithology 159 Sapsucker Woods Road Ithaca, NY 14850 607-254-1100 [log in to unmask] Our Mission: To interpret and conserve the Earth's biological diversity through research, education, and citizen science focused on birds.