I have in my music listening room 4 pairs of speakers on two systems, one a 2 channel music system, the other a quasi-home theatre. I have a pair of jbl L-166's with 12 inch woofers, a pair of JBL L-200's with 15 inch woofs, a pair of Chario Academy 1's and a pair of Spica TC-50's. Usually only 1 pair is playing at any given time... I have noticed that if one of the mini monitors is playing, the woofers on the jbl's do, if you feel them, resonate somewhat. I have never been able to hear any sound or any interference on the part of the woofers in the room. I think I remember reading an article way back by Linn stating that you should only have one pair of speakers in a room and recommended to their dealers that only 1 pair of Linn speakers should be set up in a listening room. Anyone remember that?