...Perhaps other contributers do!
A link to your previous posting
The crux of your problem
"I realise it is in the recording of them, but can it be improved?"
Distortion on the original track often causes clipping, the actual recording level being too high. I don't know of any way of restoring the sound when the recording level has gone off the scale.
Differing volume on different tracks may be improved by sound card software and probably re-recording to lift the fainter tracks, but you are then into the vast world of enhancement just like the present popularity of improving photgraphs.
in fact you could liken you audio distortion to the overexposed photo so much of the picture burned out.
I hope somone can offer a path to suit you.