so after having my system in my grand prix for about a month now and done all my playing and tuneing in it. it does rattle the trunk more then the MTXs did but tbh it dosent sound to much louder (or deeper) then my MTXs do in my blazer. info of the stuff in the GP. 2 sq HDS121 dvc4, sq q1200, box is 3qubes tuned to 33hz, 4guage power and ground rest is stock electrical, pioneer 44hd headunit, gains on amp set according to how SQ says to on there amps. iv tried the box facing into the car, into the trunk. and tbh it sounds a little better facing the trunk but comes with lots of trunk rattle. but its dosent seem as loud and as deep as a "1200" watt system should. I put "1200" because im on stock electrical so I know its not getting full 1200 but I should be getting 900-1000 atleast. iv seen vids of just 1 12 on similar power doing 3x better then my setup. so any ideas of what it could be

 

The "trunk rattling" is robbing you of a fair amount of both sound quality and SPL, as is the stock electrical. Look into some sound deadening materials for your trunk, and for your whole car if you can. It will do wonders for the sound in the car and eliminate a lot of road noise too.

How are your subs wired? They are DVC, so you have 4 4ohm voicecoils to wire together. Do you have them wired to amount to 1ohm or 4ohms? That will affect how much power the amp can put out. Is the amp stable at the ohm load you are giving it?

I'm not familiar with that amp, but hopefully someone else might chime in here. Altoncustomtech knows his stuff well and could be a good help if he chimes in, along with a few others.

 

iikikik, that's why i turned my box facing forward so more of the pressure is going into the car, but the box isn't sealed off from the trunk so theres some loss <..> wired to 1 ohm. there isn't a lot of road noise tbh. but i don't have money atm to dump into deadner. all soundqubed is Audioque renamed.

 

You will be louder inside facing the subs to the back of the car. That being said, you need to solve that trunk rattle (you wont ever completely get rid of it)

and, being that its a car, comparing it to the system in an SUV is like apples and oranges..

 

yea ik its apples to oranges BUT. when you have a system that's barely getting 300watts (blazer) and a system that can should have almost 1200w (gp) then there should be a big difference, atleast in the department of ripping the car apart lol

 

Stock electrical should run the amp pretty close to it's rated output without too much trouble. Are your lights dimming? How bad is the voltage drop? Either way if the amp was only putting out 1,000 watts vs. the rated 1,200 you'd never hear any difference anyway.

Who built the box? Are you certain it doesn't have any air leaks? Was it built to the exact specs/dimensions that I posted up?

Believe it or not, even with the big gaping slot for the port if there's any air leaks anywhere it will hurt the sound and output of the system. The most common place people have leaks and don't realize it is where the sub mounts to the baffle. Even with that rubber gasket around the frame. Any leaks on any of the seams around the enclosure are a definite problem. The easiest way to seal those is silicone, use a thin weatherstripping to seal the mounting surface of the subs.

I've always preferred have the subs turned forward and firing into the cabin of the car. However, if the front of the enclosure is not SEALED to the cabin of the vehicle then it does generally make the output much worse than when firing rear. The best plus to doing that is that when it's done right there's almost no trunk rattle, at least not any more so than the rest of the car starts doing, lol.

Something is a bit off being that the 12's aren't outperforming those old 10" MTX's by a large margin. I would say the subs need to continue to break in but after a month of healthy running they should be broke in by now. I would go after an issue with the enclosure such as air leaks first as you'd be surprised how just a tiny leak can make a big difference. Your PM to me about how it's wired didn't make a great deal of sense. A little more explanation or a picture would be most helpful. If you do indeed have it wired as the example you sent shows except that the negative from the amp to the subs is on the same sub as the positive then it is wired correctly for a one ohm load, all the coils are wired in parallel. If I were you I'd double check everything and make sure that there's not one out of phase, or a posi/negi crossed on one coil. Make sure to look at the coils to be certain the manufacturer didn't accidentally put the red/black terminal stickers on the wrong ones or swapped the terminals when building it. It's rare but does happen. For example, when you look at both the subs if the red/posi terminal is on the right hand side on three terminals but on the left on the fourth then the fourth terminal is accidentally been swapped during the build process. Like I said, it's rare but does happen.

 

about the wiring I have it correct now, went out and bought a Digital multi meter, the way I had it wired before was fluxing between 1.6 and 1.9 ohms, now I did it right and im at 1.0-1.2 ohms. I built the box, but didn't use your design, used a different one that was similar. not far off, I wouldn't of been able to get yours in my trunk at all if it was an inch taller. FYI the mtxs are 12s too. Maybe the subs just want more airspace :/

 

What's the dimensions of that design? I can double check and verify whether or not it's any issue for the subs. The one I designed was from the dimensions you gave me, were they not accurate?

I would still check everything over for air leaks. That is extremely important.

 

yes your box would of worked, if I could have fit in the trunk opening, grand prixs trunk opening is small. 33Wx16.5Hx20D I do belive