I was hoping someone could help me out , Im running 4 CF-3s .My living room is a long rectangle (ranch style home ) . Im kinda limited to speaker placement . Ive got 2 speakers at each end of the room , approx 7ft between each pair . the room is 25 ft in length .All 4 speakers are running through my Pioneer spec1 preamp and powered with the phase linear 400 amplifier. The spec 1 has the A or B or both A+B speaker selector , its A or B or both A and B speakers . The problem is when set on A the speakers sound great, set it to B the back 2 speakers sound great . When you select both A and B you lose the depth if your in the center of the room , get closer to either set of speakers and they sound( ok ) not great.But the depth comes back ( more bass). I do notice than when all 4 are going i get a cracking sound when the bass is about half way up and the volume is about noon. My freinds dont notice it until i point it out .When on A or B but not both at the same time, you crank up the bass and volume and both sets sound great, until you play them at the same time A+B. Could there be a cancellation problem ? I have double and tripple checked my wiring , all + are + and all - are -. Do i need to reverse my phase on the rear speakers . Im at a lost here, so any imfo i would greatly appreciate. Possibly could it be in the preamp A B selector control ? how about some ideas on a better choice of amplification for these CF3s I like power ( clean power ). Thanks