I have an Eclipse CD5000 deck (8v pre) connected to a 4ch MTX TA5604 (75x4 rms @ 4ohms) and a mono MTX TA5601 (1000 rms @ 1ohm). The 4ch is connected to 2 sets of Boston Acoustics Pro 6.53 components rated at 250 rms/pair and the mono is connected to 2 Sundown Audio SA12's rated at 600 rms each. Both are d4's wired to 1ohm. My problem is that there is alot of muddy mid bass (very overpowering compared to lower and higher frequencies) and everything seems to be distorting before it even gets close to a volume it should be able to handle. The closest thing I can describe to what it sounds like is a cheap alarm clock radio with the volume turned all the way up and the subs sound like they are clipping. When the volume is lowered, the alarm radio sound goes away but the sound is still muddy. I can assure you that this entire system is not even close to as loud or as clear as it should be when this happens.....any thoughts???
having both amps sound bad can almost immediately eliminate speakers and amps. So while you can still test them rather easy (external ipod hooked into a new set of mini to rca cables at the amp) i would suggest looking at the "bass" on the deck or the rca's. sounds like maybe you have some bad rca's (aka $1 store cheap) or you've got the bass boost on (eclipse doesn't have one i know), the bass cranked up high on the deck or something wrong with your crossover settings possibly.