My brother once told me, in relation to audio engineering, "you can't polish a turd".
I know almost nothing about the deep technical methods and terminology.
What I basically (think) I need to do is clean up all of the "air" from my samples. I often compose very heavy, thick music with many different instruments doubled up and many channels. What I normally end up with is a very "muddy" sound. It's hard to explain. I'm also a bit tone-deaf and tend to really reduce the volume of high-pitch trebles and bass it up. I assume this is due to all of my samples, despite being high bitrate/hertz, not being clean from the beginning. Many of them were recorded from real instruments. What I'm getting is an accumulation of all of this useless air from my samples giving the final mix a grubby muddled sound that just can't be fixed. The air is not noticeable when listening to each sample individually, but all stacks together when mixed. That's my amateur assumption.
Like I said, I have no idea how to properly refer to anything, but I am very willing to learn. My approach that I'm trying is to play with equalisation, testing the samples while isolating different frequency ranges, and finally lowering (zeroing) anything (low-bass or high-treble) that seems to be nothing but noise. This helps, but not enough, I feel. I try some filters called "hiss reduction", "reduce hum" and "compressor", but this sometimes can do more harm than good under my amateur fingers. I've heard a lot about using compressor filter, but I normally end up losing the subtle attacks and decays, which I don't want to lose, so I'm obviously not doing something correctly.
So I'd really appreciate if anyone can give me some pro advice, with some audio engineering knowledge, on how I can go about trying to "polish a turd".
While I'm at it - I'm also especially interested to learn the best ways (pro techniques) concerning what I should do before and after
trying to convert say 24bit@48KHz samples down to say 8bit@11KHz samples, for use on legacy hardware to play in a real-time game engine. I think this subject is related because I get very muddy, noisy results, teetering on the unacceptable.
Thanks for your time!