Fixing Muddy audio

[hf]

NOTE: This was originally a post on how to get SuperEQ
to work, I've figured out what I was doing wrong, but
still have the following question:

I'm just starting to play with avisynth...
I have some old instructional VHS tapes that I converted
to avi's and dumped on my hard drive. The video
and audio are both bad, but the main thing I want to
clean up is the audio so I can better understand
what the guy on the video is saying. The audio is very
quite and there is a lot of hiss.

I downloaded foobar2000 and used the equalizer to quite the
hiss somewhat and saved the settings to a file, then use
those settings for the SuperEQ() filter. That improves
the audio, but it is muddy sounding. Is there any way to make
it "crisper"? Adjusting down the upper frequencies in the
equalizer hides the hiss, but I was wondering if there is some
way to take a audio sample where there is no talking (so all
you have is the noise) and then use it to subtract out the
noise from the main audio track.

Thanks for any help you can provide!

[bb]

You should try a good audio tool like GoldWave or the free Audacity. Even Nero's Wave Editor has an amount of good functions like a noise analysis and a noise reduction. These tools work on uncompress WAV files, so if your audio is compressed, you have to decompress, edit, and recompress again.

bb

[hf]

I tried audacity. It does a pretty good job of removing
the hiss, but the audio is still really bad. Looking at
the spectrum graph audacity has it looks like there isn't
much going on beyond like 2Khz, so I think the main
problem is that the upper frequencies of the narration
are just not there. Oh well, at least the hiss is gone!