I don't use Cool edit pro, but what you want to do is pretty much the same with any DAW software program. If you're looking for "What buttons to push", I can't help you. If you're looking for "what's wrong with this recording sonically, and what can be done to improve it," then read on....

At first listen, you have a variety of common mistakes in audio capture. The sound source (at least one person speaking, maybe two) is not close enough to the microphone(s) and the background material is all over the road - probably an outdoor shot? Lavalier mics are the first thing I'd suggest, maybe a boom mic as well, cardioid pickup all the way. A limiter (NOT a compressor) would be a good idea; you could get in close to get the normal dialog levels, and then the limiter would make sure peaks and transients don't overload you inputs, as they do here in places.

A compressor is usually a bad idea here as well; when not set properly, it will "hunt" for a nominal gain level, thus cranking up you background noise, and then overshooting (and distorting) when your REAL dialog begins. It's a common default setting on consumer camcorders, audio (cassette) recorders, etc. If you can simply set things up to act as a fast limiter next time, you'll do better.

You've got low-end rumble on this as well; (music and passing vehicles) that's the first thing to be removed. Use a high pass filter (or even FFT if you have it) with a steep curve to get rid of everything below 200 or so, at least for starters. If you have a noise reduction tool, you may have some luck with sampling a bit of the background wash, putting it on your clipboard, and using that as the noise print to remove some of the BK noise.

If you have a de-clipping tool, you'll need to use it on this as well; the dialog peaks are distorted. Ditto for de-hissing. There's some system noise, (or tape hiss?) on here as well. It can use a little reduction here, too.

When you get it cleaned up (well, clean-er), you may want to do a bit more limiting to tame the dialog peaks, letting you bring up the level in general. They seem to be all over the road here, too.

You may have the option to upgrade from Cool Edit Pro to Adobe Audition (I think that's the new-parent company for this software?) THey have a spectral editor in Audition that some folks have raved over. That plug-in will give you a few more options as well, including the ability to redaw (remove) some offending things - pops, ticks, door slams, etc. It's not a miracle cure, just another tool in the arsenal against bad sound. ;-)

I fooled around with your clip using the above steps and got arguably "better" dialog with Samplitude. The problem here is that it's easy to go too far, as well, and then the whole thing starts to sound electronic and washed-out. Let me know if you want to hear it, and I'll email it to you.

THANKS for your thorough reply. I'll certainly try to follow it with the right equipment, if possible.

And yes I'd like to see your result. Could you please send it to my email, peter.valentino(at)gmail.com ?

Thanks alot.