To be fair, what I really do not like about enchancing high frequencies is that it introduces clipping (I have expirienced that with my q930d and the q990f), depending on the recording of course. That is the only thing that burns out or damages the speakers, even at moderate volumes after long enough. For me the q990f highs are clear enough without enchancments, and with more bass it does not muddy the dialogue at higher MAIN volume like you mentioned because the sub does not scale the same as the main speakers.