Concur with Juggler25. One can identify the 787 of certain operators just because of the high pitch whine on the carrier wave, and the speech does sound significantly more muffled than other types.
Upon reflection, I think all 787s have the muffled audio; but add in the whine then in a busy ops room with lots of ambient noise going on, and perhaps a crossed transmission, it gets quite difficult sometimes to understand some of them.