low volume voice, high volume noises

Hi,
I have some files of voice recording I need to clean up.
The voice volume is very low and there are many brief noises at very high volume.
I am a complete incompetent when it comes to audio. I just need to get this done and the only audio editor I ever used is Audacity. What effect/parameters I can use?

Can I somewhat script it to run on many files?
(using ubuntu gutsy here)
Thanks very much!

It sounds like you will need to use a limiter
If you’ve got the LADSPA plugins installed, look for “Hard Limiter”

With the whole track selected (You may actually be better trying this on a short section first, then using “Undo” and arepeating it on the whole track once you have found the optimal settings), set the hard limiter settings as follows:

dB Limit - set this to just a little higher than the loudest part of the voice recording
Wet level - set to maximum (1.0000)
Residue level - this one you will need to play with - the higher it is, the more of the “brief noise” peaks will be left - the lower it is, the more distortion will occur - try it at about “0.1” to start with.

This will not remove the noises, but it will reduce the level to just a little higher than the voice, allowing you to then amplify the track to get the voice louder.

Hint -
to find the level of the voice in dB, select a loud section of the voice (without the noises) and click on “Effects->Amplify”

If the noises are very brief (occasional clicks) you can use the “Repair” feature that is available in v.1.3.4, but I’m guessing it’s worse than that, hence my first reply.

Thanks a lot. It somewhat worked, though the recording is just crappy.
Any possibility of automatically applying it to many files?

The problem with trying to do it on many files as a batch opperation is that the levels may not be the same on all the files, and you need to set the limiter as close as possible to the peak voice signal.

Also you can’t use Audacities “Chains” feature, as it is limited to the built in functions and not the plug-ins.