Often the biggest problem is at the recording stage... some engineers insist on processing the sound as it is recorded... which is fine for pop music and the like, which will be heavily compressed to make the maximum noise so it comes out of the radio at a homogenised level....

When I'm recording I like to record totally 'flat' with no compression or reverb, etc., because that gives me a totally blank canvas to mix down afterwards - as if I'm still working with the performer. You can add stuff, but you can't take it away once it's recorded. If you follow my drift?