I'm making some screen casts and the sound of my computer can be heard in the background. Is there a way of filtering it out of the recording? Any command-line tools?

sox and audacity have a number of tricks. But ultimately it's easier / better to not record the noise to start with. There's a reason they make field recorders and fanless computers.

And also better to know what $&@^ mic your using. I thought my mic was just picking up lots of noise turns out after putting my hand over the mic and speaking I noticed the recording didn't change.

Then realized... I have three computers in my office, and pulseaudio didn't detect the mic on the vnc server, so it decided to get smart and found the mic on my laptop (where the vnc connection was started from) and used it.

ARR... I'm so brain dead some times.

Now that I've switched pulseaudio to use the mic fixed to my head... noise reduction isn't as much as an issue.

Thanks for the help anyways.