[Snipped from an email response to someone from whom I requested a revised mix with less compression]
Ok so, it isn’t always easy to say what’s causing what from this end. Trying to do detective work like CSI or something, figuring out what happened after the fact. But really it’s pretty simple. The track […] sounds like everything is pushing everything else out of the way all the time. Everything is fighting everything for space; as a result, there is essentially no space. And the ‘epic sound’ you seek needs space; specifically the right balance of space/separation vs intensity/density. Your stuff is way towards the latter. Separation is arguably the number one thing you need for a great master – it’s way easier to squash things together than to pull them apart. This is why I am always moaning about people overdoing compression all the time. But I digress.
Now then, the thing with your stuff is not (I’m 99.99999% sure) what you do to individual elements. Like, crunching the drums and so on. That’s fine, it’s creative and musical stuff. The root of the problem is almost certainly the interdependent stuff. That is, stuff that makes things do stuff to other things 🙂
This is why I assumed compression; if you push two things into a compressor, they fight for space, and (basically) whatever is loudest wins. But it could be other things; sidechaining means that effectively one thing pushes another out of the way. And if you’re doing that via automation of some sort, we probably have our answer. All this stuff all amounts to the same thing, whether it’s buss compression/sidechaining/automation/whatever. It makes things fight for space, which is cool – up to a point. So, do less. I have no idea how you’re approaching it, implementing it, or how much actual gain reduction is happening on individual elements in the mix, but it’s too much (sorry, being honest).
Behind all this I’d ask why you want to do it; if it’s for creative effect then I get that it’s very popular, the whole Flying Lotus thing and all that. But there’s no need to do it to everything. A pumping rhythm section with a gorgeous spacious pad floating over it is a world apart from that same pad being sidechained and pumping in and out; it robs all that space from the track, while not really adding anything to the intensity/density (which comes from the rhythm section).
If you’re doing it for ‘mix’ reasons, bear in mind that sidechaining is a last resort (more here) in my opinion anyway. A track should sound good way before you need to sidechain stuff, that just ices the cake, if you even need it.
TL;DR do less gain reduction on the interdependent ‘stuff’ (sidechaining etc), much less. Less gain reuction on fewer things. Be selective. However you’re doing it, just ease it back and get yourself a ton of space and separation – LIFE – in your mix.