Arrgghh..this 100Hz room mode is killing me. I know it's a room mode, because it manifests at maximum right above my Sweet Seat ! Also, Sub and speakers both generate it. Can't place the speakers anywhere else nor uglify the room any further due to the WAF. Tried a very steep EQ by Behringer (DSP based) and it worked, but too noisy and hummy, could be it's not getting enough juice from the preouts, for the DSP to engage properly. Isn't there some passive notch filter (VERY steep) or even active (also VERY steep) I can try?