How to remove noise on negative-voltage part of mono track

[lowerlight]

I recorded an audacity file from an old cassette tape. The tape was a mono recording, and I recorded it as a mono sound track. There is a lot of noise for the negative voltage portion of the track (the positive voltage portion of the track seem to be fine). Is there a way to get out the clean signal by some operation with the positive voltage portion?

I tried noise removal and it doesn't work for this one.

Thanks,

[kozikowski]

It's highly unusual to get a non-symmetrical audio waveform. I think one of the female announcers on KPCC can do that, but it's still unusual. It's a piece of cake, however, to get DC offset on your sound by accident which will look like more blue waveform on one side than the other. Select a piece of the show and Effect > Normalize > Remove DC Offset. Don't select anything else. Do Not actually normalize.

Cassette noise tends to be wide band, flat and impossible to remove. It's reeeeeally important to get a good profile--select a segment that has noise but no performance. If there is no such thing, you're dead.

Another note is that the noise removal tools in 1.3 are vastly better than the ones in 1.2. You can install both Audacity 1.2 and 1.3, but you can't use them both at once.

Koz