Clarion DVD head unit with a 7 inch flip out monitor , 2x Kicker CVX 12 inch Dual 4 ohm (750rms) each wired to 1 ohm in a sealed box , Orion 2400D mono channel amp wired @ 1200 watts rms 1 ohm , Memphis M-class 4 channel 75 rms x 4 , Memphis 6x9 in the rear 85 rms each , Eclipse 5.25 inch 3 way components in the front . Optima red top under the hood , Optima yellow top in the trunk , and a Kinetics cap-killer equivelent to 100 1:farad caps .

MY QUESTION IS - how do you know what frequency is best suited for your amp/sub setup - to get best spl/sq - or do you just play it by ear ?????????????

In your case, since you are only worried about a HP for the fronts/rears and a LP for the subs I'd start around 60Hz and if your fronts distort and high volumes raise the crossover frequency, and if your subs become too far forward in the car lower it. Those will be the things you mostly have to balance.

I guess to answer your question, I said by ear.

Im also haveing a problem with distortion in my rear speakers - at first i thought i may have blown them , but is it possible the frequency setting i have now is putting to much pressure on my 6x9 rear cones and causing that effet ?

Easy to check, raise your crossover and see if it goes away.

Distortion in rear speakers can be a result of the substage pressure back there in rear parcel shelf installations.

Cliff Notes: Remove em

Damnit - I shut the Orion off completly , the y rear speakers sounded fine for about 20seconds with no subs , then they started to distort - i think my amp , or my speakers may be bad , the 6x9s are 85 rms , and my amp pushes 70 rms , and its at 80% gain , i dunno - crap !

80% gain?? Do you have 2 volt preamps? I've never needed that much gain on 6 x 9's. Just turn it down, you're probably clipping it.

Gain setting tutorial in the amplifier section. At 80% gain, you are clipping it.

Oh really - thats what was recomended to me by the memphis rep - because my fronts are at 40% and i have it faeded to the front a little to take some of the output from the sub and let the amp do the work instead of the deck - this is what he explained to me , but I will check it out. thaks.

Err, that memphis rep has no idea then... I would never tell someone to just set it to a specific value. At the very least use your ear.

It was actually fine for the last 4 months though - it only started happening wen i added the 2 cvx's , im gonn go switch my amp to this 2 chnl i have layin around , so i can see if it may just b the amp - brb !

Ok - so I figured it out - I switched amps and it still sounded like crap - so i knew it had to be a speaker - setting the bal/fade to rear left/right helped me discover that the issue is my rear left 6x9 - but why would one go and not the other , and how the hell did it even go at all when I was under powering it by 20 watts rms. Ahhh whatever , Memphis - guess its time to trade in that warranty -

HOWEVER - what do you guys suggest I buy to replace these - I am deffinately getting rid of them - I was thinking ECLIPSE 8394 , or a JL VR690CXi - let me know - thanks !

Your subs may be the culprit, bass in the trunk will move the cones on your rears. Personally I do not run rears and can't stand rear fill but if you are going to get something just put some 6.5 or 7's in there instead.

/\ but you may need to "protect" them from the sub.