anyone have some links to online calculators and what not to help me build a box for 2 15s.

 

altoncustomtech will chime in here soon I bet, he designed my box for me.

 

cause im debating on weither to get 2 sa-12-d2 or 2 sa-15-d2

 

how loud are you trying to get? LOL you cant go wrong with either.

 

probly get a 2000wrms amp. but i plan on keeping it at 2ohms instead of 1. so the amp im looking at gives 1300wrmsx1channel at 2ohms, so 650w to each sub, even though the SA's can handle 1000-1500w rms easly as long at you dont clip. just going for something bigger then my old MTX thunder 4500s that only have 150rms, an the old TIS20 T510-PK 5 channel. but i got all the system and wires for free, only thing i bought was my radio, which is a Pioneer 44HD. latter on down the road in like 10 years when money allows it ill have a wall with 18s with 10k+watts. but 1000-2000watts will make me happy compared to like what, 300w max? XD lol

 

Dual 15's is going to eat up the entire rear of the truck for the proper sized enclosure with fair port area. A pair of 12's would be much better suited unless of course you don't mind not being able to see out your rear window and/or loosing the use of the back seat.

The upgrade you have planned is a good one. Running the amp at 2 ohms instead of 1 is easier on the electrical, easier on the amp, and can result in better sound due to better damping, less distortion, etc. Also, there would barely be any audible difference in output running the amp at 1 ohm for 2,000 watts as opposed to 2 ohm for 1,300. More power is the least efficient way to get louder.

If I were you, the pair of SA-12's on the amp you're looking at (which one by the way?) would definitely be the way to go. What are your maximum dimensions? As Rich said, I can help you with the enclosure design.

 

use torres box calculator just google it its the best one out there it calcs displacements for you and port area. theres plenty of room for 2 15s in a blazer. especially sundowns because they don't require much air space like other 15s do. and another thing to add is that stock electrical isn't made for systems and can only handle about 1000 - 1200 watts total I only say this from experience. anything higher your head lights and interior lights will start dimming like crazy.

 

Sundown shows a range of 3cuft to 4cuft per sub for a ported enclosure for those subs. The larger size enclosure will have a smoother response along with more efficiency which will help the OP on output since unlike most SA series sub owners will actually be putting around RMS power to the subs.

So, an 8cuft NET enclosure, tuned to 32hz with about 116sqin of port area will measure 34" wide (widest width that can fit in the back) 18" tall (almost level with the back seat head rests) and then would need to be 36" deep (won't fit behind the rear seats) to size for that enclosure. That's not including bracing or any sort of double baffle.

Yes, 15's will fit, the enclosure could be smaller, the port area less, etc. Even at 7cuft NET and everything else the same the enclosure would need to be 32" long, not saving much on space, plus that would be a crazy tight fit. In my mind, the real question is whether or not the OP is willing to give up that much of his space or not. If so, then two 15's is doable, if not then 12's would be the better choice. Besides, if this is for a daily driver and no competing will be done with it then would 15's REALLY be any sort of necessary? All these questions and more need considered and answered before suggesting a setup and designing for it.

 

38 is the max width in blazer to fit between the wheel wells
you could do 38w 20h and 28d with .34 being the displacement and after all the calculating will get you 10.2 cuft then after port displacements and every thing it would be 8.39 cuft at 35.56hz with 111sq in port would be 18.5h 6w and 19.5 d. you have to do sub up port back and if you want to brace it you got plenty of airspace to spare for bracing and keeping it up or right at 8 cuft

 

yes my blazer is my DD, but im a bass head, and if i ever need to actuy haul something i have my dads truck :3. ik the SA2500Dv.2 would probly be the better amp cause sundown with sundown products, but the amp I was looking at was a soundstream TA1.2000D TA1.2000D - Tarantula - Amplifiers - Car Audio