Noise removel not so successful

[TheNewNumber2]

I'm a newbie to Audacity. I originally downloaded it for the person who owns the computer, so they could use a feature, but I knew I'd get my hands into it sooner or later, and yesterday was my day.

Today I tried something new. I tried Noise Removal.

I edited out a track from a suite on a CD. Before the track begins, there is this deep, thunderous sound that dies off, but fades in with hte beginning of the track -- a single instrument performing the beginning.

I tried the loud part of the noise and applied that and when I filtered it out, it just muted the whole thing to where you can't hear the beginning.

So then I opted, thinking that initial sample of the noise was too far into the frequnecy, to go with the quieter part right before the cue starts to fade in. This worked, but the opening instrument now sound like a muted whistle -- not at all what it is supposed to sound like.

Can anyone suggest to me what to do to get this track clean? Keeping in mind I have no idea what I am doing.

[steve]

Can you upload the first few seconds or so somewhere on the internet and post a link so that we can have a go with it.
If you don't have any web space, try a file hosting site like mp3space.com
Upload it as a 16 bit 44.1 kHz wav file so that we have a good quality sample to work with, and chop it down to just the relevant few seconds so that the file size is not too big.

[TheNewNumber2]

Thank you, stevethefiddle.

Here are the first five or six seconds of the piece which includes the sound, and then just the music after it's fully died down:

http://www.zshare.net/audio/15665579156fbe67/

[steve]

I can get rid of most of it with a high pass filter set to 200Hz.
When the music starts, there is very little below about 300 Hz, but most of the "deep, thunderous sound" is below 100 Hz, so using a "High Pass" filter set to 200 Hz removes much of the rumble with very little effect on the music.

The high pass filter plug-in is available here: http://audacityteam.org/download/nyquistplugins

I recommend Audacity 1.3.x for this kind of work.

If you could also post a link to the bit just before that sample - where there is just the rumble, but before the music starts, it may be possible to reduce the unwanted noise even further.

[TheNewNumber2]

Here is a longer sample. From the loudest peak of the noise, and some extra music incase that helps:

http://www.zshare.net/audio/15743875956483b9/

[TheNewNumber2]

Anybody had a chance to mess with it?

[steve]

Sorry, I thought that I'd replied to this.

High pass filter applied for the duration of the unwanted noise. That will get rid of nearly all of it.

If you want to eliminate it altogether, copy some samples of the first few notes and adjust the pitch of them to match the original notes, then replace the original notes with your new notes (rather fiddly, but it can be done).

[TheNewNumber2]

I tried High Pass Filter jsut now. It worked quite well, but didn't take the noise out fully, and sadly when the part where it filtered out passes, the volumes just back up, so it's broken the feel and flow of the beginning of the track.
And it sounds like it affected the music a little as well.

High Pass Filter (LFO) has more options, but I am not an audio geek and dont' know how to adjust those setting properly.


Thank you for responding! I know this can be done, I got a crappy MP3 from years ago before I bought the CD and someone managed to get the sound out.

[kozikowski]

Note nobody is trying to use the Noise Removal Tool.

Noise Removal only works with noise that doesn't change over the duration of the show.

Koz

[TheNewNumber2]

The most complicated thing I have ever done with a music program, is use Exact Audio Copy to check spectral analysis. I'm a newbie here, and I don't know that, or much of anything else in regards to Audacity.

Still hoping someone can help.