To remove a whistle each band has to be about 100Hz wide , or less, within the whistle frequency range.
At that high-resolution, processing on my (five year old computer) take several times the duration of the track,
standard de-essing which only requires bands say 1kHz wide is a lot quicker: less than duration.
(ln(4800 / 3800) / 10 ) / ln 2 = 0.0337 octaves per band, or 0 steps and 40.44 cents.
Those are REALLY narrow bands! Isn’t that excessive for good results? My default settings, which I find satisfactory for blanket treatment of tracks, are 10 bands between 2500 and 8000 which works out to 2 steps 1.37 cents, call it two.
This math isn’t very exotic – graphic equalizer sliders are logarithmic too, after all – and Audacity’s graphic equalizer has 4 steps per band, so I only halved that width for my defaults.
Narrower bands are more expensive to calculate than wider ones, and lower frequency bands are more expensive than higher.
My intention was to write something that removes naturally occurring but distracting mouth noises from narration. It was not my intention to fix the noises of damaged old media. Fixing spikes in a signal may actually be a different problem from fixing small natural sounds of short duration. But, if you think it works, you’re welcome!
As it happens I was just lately looking around for good books about Audacity for instructing other people, I don’t know if you have recommendations, and I found one just about fixing up old 78 rpm’s, which is free if you have Kindle Unlimited. I think there are some interesting ideas here.
DeCrackle looks like the DeClick problem but on a smaller time-scale, so a DeClicker will also DeCrackle, but inevitably involves a lot more computational effort because the occurrence is more frequent.
The lower limits of the “repair interval” and “precision” maybe need to be lowered for DeCrackling because of the shorter time scale compared with DeClicking.
The DeCrackle sounds smoother than paid-for software like Brian Davies “click repair”, see attachment ,
( but to be fair the processing-time is easily 20x longer than Brian Davies ).
Did you reduce the minimum separation permitted between clicks? It is undesirable to put it much lower than the default, I find, for editing my own male voice. It would muffle too much. As it is, it muffles the vocal fry a bit, that ends of sentences sometimes trail into.