...something that ashcat suggested here.
I appreciate the namedrop and I'm glad I could help.
It never made sense to me, though, to try to do anything to peaks
before you adjust for average level. I think it's a holdover from analog workflow, but even then it didn't make a whole lot of sense. I put my lookahead RMS leveler first and then the saturation that I use to control peaks.
Actually, my mastering chain is:
ReaEQ to shelf down the low end and maybe a couple other things for "preemphasis" to sort of shape and focus the action of the compressor.
ReaComp as a long slow RMS leveler with lookahead set to the very lowest ratio with the knee cranked way up and threshold set so that it pretty much never gets to out of the knee. It's almost always doing something but never really doing much.
ReaEQ for deemphasis (shelf the low end back up) and any final spectrum shaping I might want.
Saturation to round off the very tops of the very loud things and make sure that whatever happens it will never ever actually be as loud as X. I don't trust limiters with time constants. They can't promise you a ceiling unless they also add saturation or clipping.
In the end it's not much more than pounding it to tape and letting it distort if it wants to, but it works.
BUT I'm always mastering things that I have also mixed. Usually I do end up slapping that chain on the actual mix project toward the end and kind of finishing the mix through it. I do my best to control the dynamics at every stage from performance to track level compression or saturation to group/bus level so that at the Master is just about some glue and some "aberrant" peaks from when everything just happens to push the same direction at the same time. If it's a one off, I'm done. Render it, see where the peaks fall, adjust the master fader to make that -0.6dbFS, render final. If I'm compiling an album I usually bypass the Master chain, render to floating point so that I don't have to care about absolute levels, and bring it into an album master session with about the same chain.
When you're mastering for other people, it's sometimes more about rescue and repair and that's when you usually do have to do a lot more than just "slam it to tape". I'm kind of glad I don't have to do that kind of thing, but I'd be happy to if there was money on the table.