Your electronics have already been designed to address any of those things for most residential and even professional/industrial applications. Save your money. McIntosh wouldn't skimp on cables anyway.
Interesting about the 8khz. I hadn't noticed but I'll try your EQ "fix" and see if it makes any difference. Do you set the 'trim' controls on the front baffle to anything other than 0?
Pretty sure Paul said the exact same thing every time a previous free, revolutionary firmware "upgrade" came out. Best improvement in audio he's heard in 50 years! LOL I wish my hearing was as good and discerning as Paul's, and I'm probably 20+ years younger.
Came up earlier in the thread, but yes, I also have a good "phantom center" effect in my living room with two JBL 4349s for L/R toed in slightly and angled up according to whatever the native slope is on the stands I bought for them from Deer Creek, back when they were still selling them. Had...
I actually don't even use a center channel speaker at all for most movies. Seems to work great with the 4349s on either side, TV speakers off, and no sub needed. I guess in typical "surround" situations maybe the center does do a lot of the work.
How bad really is the 520c and since it's only usually used for center channel dialog and whatever background noise and music make it to the center, is it really a big deal?
Yeah it's a nice player, but frankly in terms of operation it's pretty clunky (by design I guess). Also since I don't have a use for it in my living room, the fact that a lot of the functionality is only visible via the on-screen display (to a TV), makes it too difficult to use in my office.
I couldn't delete the thread, but I've received enough messages such that I'm going through them in order. If it falls through, I'll edit this again, but for now the Oppo is considered taken.