I’m restoring an old audio that was originally on cassette tape. So, all the way through the recording it has a knocking sound, ……as if the central spindle or some other part of the cassette was knocking together during the original recording. There is a repeated rhythmic kind of knock every second or two, it’s really obvious throughout the recording. The audio is of a female choir concert given about 20 years ago. I have added a small sample audio with this post to give you an idea of my problem. I took the sample audio from a portion of the recording where there is just someone speaking, where the knocking is more clear to give you some idea of what the problem is. Of course I want to get rid of that knocking and I would be very glad if someone could tell me how to minimise it or remove it entirely using Audacity, or any other software for that matter.
Kind regards Richard Milner