@jbhiller I´m not using a subwoofer yet but I´m waiting for a reply from a dealer who is willing to send me two to compare (Rel T/7x and SVS PB 1000 Pro). The EQ I´m using is basically only to push the lows a bit. It also shows that the Cornwalls lack in that area (for my taste) but first and foremost it so much helps to give depth, just as you say. I´m hoping a sub will do that to an even bigger extent and that it will give the recordings I find (for lack of better words) crowded more room to breathe.
I like Albini´s productions for capturing a live feeling and directness which does not automatically translate into pure sonics as can be found on recordings considered good by audiophiles. You said muddy... Maybe I myself have to listen to it with open ears again, I´m such a fan.
Two years or so ago he recorded the newest album by SUNNO))), the drone-doom duo that basically plays guitar-generated soundwaves*. Compared to their other albums the resulting „Life Metal“ manages to leave room to breathe in the overall oppressing wall of sound. He´s done a stellar job there.
As for Nirvana: I find it hard to tell which mixes I like better, the re-mixed versions of „Heart Shaped Box“ and „All Apologies“ are just so familiar, those are the version I came to like. Albini´s are also great, the roughness and all. As far as I know it´s just these two that were fiddled with, the rest is all Albini.