Auralex subdude

i have subdudes under my sunfire hrs subs {2} on a suspended carpeted wood floor. great bass performance. i also had them under my 2 sunfire crm-2's on spikeed sunfire stands. one day i removed them form the monitors and a livliness and musical beauty returned to the sound. i then stated using the 2 subdudes for amp stands instead. i had read that one should avoid "exciting" the room floor and walls. but in my case the sunfire monitor speakers did not work well at all with the subdudes. any explanations for this? thanks

thanks jtcf. how far into the room do you place the crm-2s. my room is 16 x 18 and i have mine 3 feet into the room with the subs 1 foot from the rear wall[not in the corners].i saw bob carver discussing 24 inches but that would be behind the parallel of the television.