OK
(though the picture is not obtained through (rightclick >) Options > Filters > AC3Filter > [Main]).
Suppose you also read the thread I referred to (and that Auto gain control isn't selected), so that it will most likely have something to do with the AC3Filter-version you're using (I'm still using version 1.46).
Other items which may be of influence are
- BS.Player's Equalizer settings
- any WinAmp2 DSP plugin used (rightclick > Audio > DSP plugin > ...)