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Re: New noise removal algorithm
Posted: Tue Sep 28, 2010 7:55 pm
by scaud
stevethefiddle wrote:In Audacity 1.3.13, if you set the "Sensitivity" to zero and the "Attack/Decay" to zero then it is identical to Noise Removal in Audacity 1.3.12.
I think I tried Sensitivity 0, Signal Sensitivity 0, and Attack/Decay 0 so perhaps it is my selections for Signal Profile that are giving me worse results than 1.3.12. I tried capturing a short section of pure signal and also tried capturing a mix of signal and noise (per Marco's email suggestion).
Taking Gale's suggestion above, I just tried choosing a particularly loud selection for the Signal Profile and that appears to improve performance a great deal.
Re: New noise removal algorithm
Posted: Tue Sep 28, 2010 9:26 pm
by steve
Actually I may not have been correct. The version I was using was Sept 20th build which does not have the "Signal Profile". I wasn't aware that between the 20th and the 23rd the new experimental Noise Removal had been enabled.
Re: New noise removal algorithm
Posted: Tue Sep 28, 2010 9:53 pm
by billw58
stevethefiddle wrote:Actually I may not have been correct. The version I was using was Sept 20th build which does not have the "Signal Profile". I wasn't aware that between the 20th and the 23rd the new experimental Noise Removal had been enabled.
It's not in the 1.3.13 Sept 25 Mac nightly.
-- Bill
Re: New noise removal algorithm
Posted: Wed Sep 29, 2010 7:17 am
by Gale Andrews
scaud wrote:stevethefiddle wrote:In Audacity 1.3.13, if you set the "Sensitivity" to zero and the "Attack/Decay" to zero then it is identical to Noise Removal in Audacity 1.3.12.
I think I tried Sensitivity 0, Signal Sensitivity 0, and Attack/Decay 0 so perhaps it is my selections for Signal Profile that are giving me worse results than 1.3.12. I tried capturing a short section of pure signal and also tried capturing a mix of signal and noise (per Marco's email suggestion).
Taking Gale's suggestion above, I just tried choosing a particularly loud selection for the Signal Profile and that appears to improve performance a great deal.
It is important with the new code that if you grab a "Noise Profile" you also grab a loud "signal + noise" sample with "Get Signal Profile". In the unlikely event you have a section that really is "signal + no noise" that is I assume to be preferred for the signal profile if you grab the noise profile as well as the signal profile. I think Marco intends that both profiles be captured for best results.
That said, grabbing both profiles then removing noise doesn't (on a few tests with a tone mixed with noise) seem to give that much better results than grabbing just a signal profile then removing noise.
Whether you capture both profiles or only the signal profile, if the noise is loud you may still need to bring up the Sensitivity slider to increase the amount of noise that is removed, and that will reduce the amplitude of the output.
Just to clarify, the Signal Profile algorithm has not been committed (and I don't expect it to be any time soon). It is only currently in the Windows Unicode Nightly because I applied Marco's Signal Profile patch to it to see if we could get him some feedback with real life samples.
Gale