CEDAR for Pyramix 64: Dethump
Restoring low frequency thumps of up to 100,000 samples duration
Thumps may last for many hundreds of milliseconds, so conventional declicking processes are unsuitable for restoring audio containing them. Furthermore, the spectral content of thumps will usually overlap the genuine signal, so simple high-pass or band-reject filters cannot remove them without degrading the underlying signal.
Dethump uses the data in and around the damaged signal to build up a picture of what the low frequency data should have been had the thump not occurred. The process then replaces the thump with restored low frequency audio, leaving the undamaged high frequency audio unaffected. This makes dethump ideal for removing many of the previously intractable problems associated with optical soundtracks, as well as for restoring damaged cylinders and discs, and for cleaning modern recordings when, for example, microphones and stands are bumped. No other process can analyse and restore damaged signal of up to 100,000 samples duration.