3 memphis m312d4 subs

i was trying to find some answers to my dilemma, i have 3 memphis m3 12's dual 4 voice coils, and two amps. my firsdtt question is which amp would work better. one is a memphis pr1.1000 (1000 watt at 1 ohm  mono block) and i just got a hifonics bxi2008d ( 2000 watt at 1 ohm mono block). my second question is what is a good size enclosure for the subs a t uning frequency. i put them all in seperate boxes 2 cubic ft tuned at 34 herts and they sound horrible. had just two before in 3.5 cubic ft box tuned at 40 hertz and they sounded great. any infoe would help a;ot

thank you

For box spec we need to know what kinda room you have to help you there. As far as it sounding bad it could be a number of issues.  You may be getting cancelation due to the way you have the 3 boxes arranged making it sound bad. Another good possibility is you now you are running a 2.66 ohm load and you are not getting  the power to the subs like  before.

My suggestions. Sell both the amps you have now and buy something that is a higher output 2 ohm stable mono block. ( Kicker zx1500.1 or something similar)or if you have the money you can do an amp that will do the lower .5 ohm stable(MMATS D2100.05 or similar). you only have 2 real options running 3 dual 4ohm subs to one amp. A .66 load or a 2.66 load.( with the exception or running one coil per sub. If you choose to do this remeber you will only get 250rms per sub not the 500rms it states.) but doing that you would have a 1.33 ohm load and the pr1. 1000 would be fine on them but the overall output will not be as good as if you ran a full 1500watts rms they can handle to there dual coils.

vehicle is a 1990 cadillac sedan deville

max width across the frt of trunk is 36 inches 

max width at rear of trunk is approx 45 inches

and trunk is 40 inches deep

only 15 inches tall due to trunk springs in rear

these are max measurement of trunk hope this will help

A single chamber as said before above would work fine. If you liked the sound of the 3.5 cu.ft. better than the 2 cu.ft. i would probably do  9 cu.ft for all 3 in a single chamber. You should have good room to do this from the max dementions you gave. 

I had two in a 3.5 cu ft box before I just bought one more i think 9 cu ft may Be too big too. i also been experimenting all week with the amps and found the memphis amp sounds better than the hifonics amp in sound quality and seem to produe moore power. I used win isd to make thses boxes and i dont like them the box for just the first two was memphis spec (actually slightly smaller). if anybody has a program to find a good size that would be great also need port size too. Thses were my second ported boxes i built have not quite got the concept of how to read a graph just yet of what sound good

the t/s paramters are

fs  31.01hz

qms  3.24

qes 0.32

qts  0.29

xmax (linear)  9.14mm

sensitivity 2.83 volts series  89.36db

sensitivity 2.83 volts parallel  95.75db

sd  0.053m2

vas  1.95cf

vas  55.30 liters

continuos power 500 watts

max power 1000 watts

and these are dual 4 ohms voice coil speakers

I've got 2 in 7 cubic ft, works perfect, in a honda civic hatch, the whole car is flexing i can give you more specs and pics if you want on what i have, they also work good in memphis reccomended mojo specs, i don't remember the exact dimensions on the box, but i have built both and have had mine in both, they are terrible in sealed enclosure, i will find the exact specs i have and post them