Audacity Forum

Summarizing problems: 1) attack/decay times are half as long as they should be. Test case already described. Have fix. 2) Resulting sound always has a 1024 sample fade-in from 0. Could fix. 3) Attenuated sounds sometimes rise again in the last 1024 samples, as seen in test cases for (4). Different e...

More thought and experiment, and I discovered another possible problem with Noise Removal. Here is a test case: Use the former extreme example of a loud 11025 Hz sine wave for Noise Profile, and white noise as the sound to process. Use 48 dB of noise reduction and ZERO frequency smoothing. Look at t...

How many other effects follow this patter of Fourier transform, change of coefficients, then inverse transform? NoiseRemoval includes most of the work for that. Perhaps the common part should be abstracted into another subclass of Effect. Thought now it seems NoiseRemoval doesn't get the handling of...

Maybe there is something below 43 Hz that is not really DC but excites that lowest band of the FFT variably?

Will you test a few-lines change if I write it for you? Um, are you having problems compiling Audacity? What platform are you on? Windows, and I am not having problems, but surely somebody else has to test my proposed patches. Try this, to demonstrate that attack times are only half as long as they...

"G-mean equals A-mean over dB-values." Yes, the ApplyFreqSmoothing function has always done arithmetic averaging. But whereas originally it did that to dB values, version 9290 caused it to be done to gain factors. I think in this case it makes sense to have "A-mean over dB-values" or the equivalent ...

I see there is something weird going on at start and end. In my examples, in fact the last 1024 samples of DC or Nyquist frequency are not silenced but fade in with a half a Hann window. When I attempt a fix, now the beginning of the sound has such a fade in. Something else seems off and I didn't ca...

Steve discovered a while ago that The overlapping FFT windows each remove the DC offset over the period of each window. That just leaves the final window that does not have the offset completely removed. Apart from the final glitch, the DC removal is arguably better than in Normalize if the whole t...

These changes were simply mistakes introduced in version 9290 which was supposed to be for performance only. In my opinion, Normalizer should be made a better Normalizer. It is not the purpose of this effect to normalize. I have also written a fix for the frequency smoothing which accidentally becam...

I have posted at Nabble too. http://audacity.238276.n2.nabble.com/bu ... 62446.html