Well I'm thinking of adding some subs to my 2001 Suburban. I pretty much decided on four 12 inch subs and obviously an amp. What do you guys think of this set-up and how do you think it will sound. I've put systems in several cars, and they sounded great. But filling a small car with bass is quite a bit different that filling a Suburban will bass. The two 12's I had in my Lexus IS300 sounded awesome in the IS300, but it sounds like crap in the Suburban.
Speakers:

Four (4) Sony Xplod XS-L121P5
Frequency response 18-2,000 Hz
Power handling 350 watts
Peak power handling 1200 watts
Sensitivity 89 dB
Top-mount depth 6-5/16"
Sealed box volume: 1.0 cubic feet
Ported box volume: 1.58 cubic feet.
Rubber surround
Amps - Sony or Profile
Sony:

Sony XM-2165GTX XPLOD
1000W max power
165W x 2 into 4Ohms, 20Hz - 20kHz, @ 0.1% THD
200W x 2 into 2Ohms, 20 - 20kHz, @ 0.15% THD
400W x 1 into 4Ohms, 20Hz - 20kHz, @ 0.1% THD
Class AB
Variable 50 - 300Hz Low Pass Filter
40Hz EQ Boost
RCA & Speaker Level Inputs
Speaker Impedance : 2 - 8Ohms stereo, 4 - 8Ohms mono
Frequency Response : 5 - 50kHz
Input level range : 0.3 - 6V (RCA), 1.2 - 12V (High level)
Power Supply Voltage range : 10.5 - 16V
Current drain (at rated output 4Ohms) : 42 A
Profile:
Profile CA800 2 CHANNEL 800W
Peak Output Power: 400W x 2
RMS Output Power (4 Ohms): 200W x 2
RMS Output Power (2 Ohms): 300w x 2
Bridged RMS Output Power (4 Ohms): 600W x 1
Dual MOSFET Power Supply
THD: <0.07%
Signal / Noise Ratio: 102dB
High Level Inputs
Variable Bass Boost at 45Hz: 0-12dB
Switchable Crossover: High Pass / Off / Low Pass
Variable Crossover Frequency: 40Hz - 500Hz
What kind of subs and amp were you using on the 2 12's? I am getting ready to redo my enitre sub set up and was using 3 12's and think is too much. I have a 2000 suburban. I am using JL 12w6's and a PPI PC2350 to run the 12's and have 2 JL 18w6's also running off a PC350. I just have the 18's in there for fun and am not sure if will use them in the next set up. If you get good enough subs and a good enough amp, 2 12's are perfect for a suburban. Make sure you have the right box size and that you have dynamatted the entire vehicle. That is one thing I didn't go all out on and I can see now that I should have. I plan on gutting everything and droppin an ass load on dynamat now. Don't like the rattles. I hope you get yours to sounding better, and look forward to seeing what you go with.
me personally, i like to tune a box lower when using it in an suv. i dont think the cabin gain is quite as pronounced when the subs are in the same "room", so to speak, as opposed to being in a trunk. that might be why the subs sounded good when in your car, but not in your suv. my friend has the same Sony amp, with two 12" pioneers, and it sounds pretty good, though not as clean as some other amps, but it has plenty of power. in my opinion, i think a 1.3- 1.5 cft sealed box would make these play real good and low, but they might not "hit"
real hard. again, just my opinion.
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toyota echo...perfect sound named vehicle