Only on some channels, e.g. 504 (NBC), very low sound level (hardly audible) during regular program, but normal (loud) sound level during commercials.
Details: Verizon fios STB, HDMI, new Samsung TV, optical sound cable to Denon AVR, separate speakers.
Sound normal when only built-in speaker is used (which is poor sound quality for music).
Has anybody experienced this problem of different sound levels between show and commercial?