The Swezey Digital Filter
Removing Crackle from Phonograph Recordings
Crackle is probably the most difficult problem to deal with when restoring old phonograph recordings.
Crackle is similar to "pops and clicks" except it is continuous
and lies buried within the signal itself.
This makes it almost impossible to separate out.
Decrackling is one of the areas in digital signal processing (DSP) theory
that still needs significant research and development.
I am unaware of any general solution to this problem.
To address this I have developed several algorithms which depending on the record
can significantly decrackle it.
Below is a brief excerpt from MGM Record 30582-A
played by David Rose And His Orchestra.
To hear (or download) the unfiltered "before" version
To hear (or download) the filtered "after" version
Both excerpts are MPEG mp3 audio files. If you need help playing these files
Thank you for your interest in the Swezey Digital Filter Program!
To return to the Phonograph page
(c) 2009, Thomas F. Swezey. All rights reserved.