For me, sibilance or shrill highs with the HD800's are a result of either a poor recording or poor pairing with the rest of your gear. I am enjoying the HD800's, Wyred 4 Sound DAC2 DSDse and the ALO Audio Studio Six at the moment and it is revelatory. Incredible balance. Clean and clear across all frequencies. Whenever I have been exposed to highs that were not good, making a change of either the amp or DAC (or a couple times a cable) cleared up the issue. As always YMMV.