What causes wobbly sound on audio cassettes?
Jun 21, 2014 at 11:14PM Audio cassettes generally last a long time. (we have many in our library that are more than 30 years old) however we're starting to get a few come in for digitsing that are exhibiting problems. Before you throw them away - let us see what we can do with them. Usually the tapes will play ok in our professional cassette decks but every now and then we'll have to explore the problems more deeply to get a good quality transfer.
Ampex audio cassette
We recently received a tape of an oral history project that was recorded in 1985. During the assessment process we found that it would play for around 3 minutes and then start to play back erraticly, eventually slowling to a stop. You can hear the effect here and it might be something you've heard before and then thrown the tape away. Sometimes people think the tape has "stretched" in fact tape is very robust and that's a rare occurence.
There are a couple of possible reasons for this playback problem and with some careful work we've been able to retrieve the audio. With this particular tape it was a one-off recording, no other copies exist so it was of great importance and we had to do our best to get a good copy.
Could this cassette tape be exhibiting a problem we usually find only with reel to reel tapes called "sticky tape syndrome"? We've only just started to find cassettes with this problem but it was certainly old enough to be a candidate.
We have a special temperature controlled oven for "baking" audio tapes to stabilise the tape surface. (Warning: Please do not attempt to do this yourself as you may ruin the tape permanently) When we've gone through this process it gives us enough time to do the digital transfer of the tapes. In this case a few hours in the oven stabilised the tape surface enough for us to be able to make a copy and then go through our audio restoration processes to improve the audio.
You can hear the result of the new transfer here.
The client was fortunate that this tape was caught in time before it became completely unplayable and we've been able to retrieve the important interview contained on it.
If you have a library of tapes that are approaching 15-20 years old it would be a good idea to have them checked and transferred to another format as soon as possible,
Call us on 9375 3902 if you'd like us to assess your audio tapes.