A new audacity trick

[reggind]

I was listening to a file tonight and the people were whispering to each other, but it was too fast and too muffled to make out exactly what they were saying. I was able to slow it down with 3 passes of -15% tempo reduction per pass and I was finally able to make it out. But as many of you know, if you stretch an audio file out too much the interpolated information gives the file kind of an unnatural almost reverberation sound. This bugged me last night and I thought on it. My first thought was to try a notch filter and see if I could take out the nasty peak that seems to be accented. This idea may have some merit, but I hate trying to tune the notch filters in Audacity. You can not do it in near real time, it is a very iterative process. Scratch that. Next I wondered if there was a way to push the artifacts up in frequency so they would be out of the normal speech band which is roughly 300 to 3000 Hz. That idea will not work, the more you slow the file down, the lower the artifact frequencies will be. I suspect for small slow downs like 5% the reason they do not sound bad is that the artifacts are mostly ultrasonic. That being said, I don't give up easy.. I found a place in the file that just had the room noise background and the artifacts from that, and I used that as the seed for a noise reduction pass. This worked slightly better than I expected it to. So, if you want to try slowing something down, and you want to get rid of the weird sounding artifacts, try using a sample of the rooms background noise, and the noise reduction effect. See what you think.

[sndprv]

I now prefer to use WavePad Sound Editor for large sound files - I've noticed that the file loads up a lot faster
than it does in Audacity 1.2.6 (that I also use). So far, I've only done very quick and basic noise reduction in WavePad.

[reggind]

I used a bunch of NCH stuff at one point and liked it OK, but it started doing something, begging or telling me my demo time was up, I honestly forget but it was enough to make me dump all of their stuff and go with free alternatives. I do agree though Audacity can take a while to start up, even on a fast machine.

[sndprv]

I just use the unlicensed, non-commercial, home use (free) version.