I did a similar test with AAC, which as I understand it (not a compression engineer) doesn't suffer from the same 16KHz problem. 64kbps vs 128kbps (p = .01) 1

I did a similar test with AAC, which as I understand it (not a compression engineer) doesn't suffer from the same 16KHz problem. 64kbps vs 128kbps (p = .01) 128kbps vs 192kbps (p = .02) 192kbps vs 256kbps (p = .05) 256kbps vs 320kbps (p = .16) This test taught me that (for my ears), AAC 256kbps is a good all-around codec for my music. You should do your own test (you might hear differently than me, apparently I hear differently than everyone in the Gizmodo and Maximum PC "studies"). But I would be surprised if it was simply a coincidence that Apple chose to standardize on 256kbps AAC, exactly the point where I have serious trouble distinguishing bitrates.