First-time enclosure specs look ok?

[CeleronXXX]

I have decided to tackle these boxes on my own. I have access to a wood shop at work so I should have all the tools I need. After many mock ups and failures I finally found dimensions that will get me two boxes that will both fit in my trunk. I came up with 19w 16h 24l. This will give me 3.3 cubes using 3/4 mdf. I also came to a port size of 2.5x 14.5 x 19. That should give me 3 net at 35hz. Does this look good and is it ok to have a box so much longer than wide and is it also okay to not have the port in the shape of an L an instead just running parallel with the on wall? Boxes are for Sa15s btw

Click to read more...

 

[ancorp 10+ year member]

The port (with one common wall, and one wall of its own) will take up 3.25 x 14.5 x 19 = 0.52 cubes. SA-15 displacement = 0.17 cubes. So you end up with about 2.6 cubes net. You're much better off with a pair of SA 10s. Or a SA 12.

 

[CeleronXXX]

I had to change the port design because I had to much port area. It's now 2x14.5x15. I calculated 2.90 net after port and sub displacement which with 1000rms should be okay from what I've read

 

[ancorp 10+ year member]

That port displaces .35 and the sub .17 - 2.78 net.

2x14.5 is 29" of port area - 10.4" per cube. Not enough port area in my opinion. What amp or amps are you running for bass?

 

[CeleronXXX]

I agree about the port area. I'm confused.then...because with the original posts port dimensions I thought I had to much port...so I changed it and got 57 inches of port. I must've goofed something up. Plan on running an scv2000. I need to get 16 inches per cube

 

[ancorp 10+ year member]

Does it have to be two split boxes or could you build one single box? Are those the absolute maximum dimensions? I still say trade them for a pair of SA 12s. With 16" per cube, you should end up with about 2.5 cubes net per driver maximum.

If you insist on two SA 15s anyway - I would do a single box (if it could fit just as well as two separate ones), with a flared round port firing to the side. At minimum a nice 6", but preferably an 8" or two 6" flared (very important) ports.

If you can mount them inverted, you will be able to get 6 cubes net tuned to 35hz with two 6" flared ports around 16.5" long. That's what I would do if I were in your situation.

 

[CeleronXXX]

Unfortunately it has to be two boxes. I planned on sealing of the trunk and firing into the cabin. I just played with the numbers again and adjusted the width to 19.5. That is the maximum I can do. But with a port dimension of 2.5x14.5x20 that gives me 35hz and 13.5 port area, with 2.69 cubes net per sub. With 1000rms per sub do you think it will still sound decent and get loud? I can always go back to the drawing board if these don't work. When I called sundown they said it falls within range and should be okay with the additional power, but I didn't give them any specifics other than net cubes of the prefab I was looking at which was 2.75 and the rms I was planning to run.

 

[CeleronXXX]

I have a 15.5 cube trunk its just the trunk opening is so friggin small. If this doesn't work I may look in into building something in place I the trunk, I didn't want to loose access to the spare which I why I decided not to for now. I also need to mention that although I've had a system in almost every car I've owned this I the first one im trying to build so particular and by factory specs. I've always just thrown what I could get into a trunk. My last system was two audiobahn 15s sealed on a jbl1200, and it was decent to me. I hope what im building with the boxes I've designed thus far will blow that away

 

[ancorp 10+ year member]

Could you slide the box from the inside? My vehicle (Mazda 3 sedan) would allow for at most about 4-4.5 cubes net from the trunk lid opening. I removed the rear seats and some of the plastic trim, and was able to slide in a 7 cube net box.

http://i10.photobucket.com/albums/a119/ancorp/Mazda3Trunk/20140728_185107.jpg

If you build it right, it will blow you away by comparison to your old system. Make sure you have enough electrical to run the 2k amplifier also.

For SPL purposes a smaller box such as your design (2.7 cubes) would work, if not smaller. But for daily I'd want 3.5 cubes per 15" if not more. You can always build it and see how you like it. With the smaller box you'd lose low end.

 

[CeleronXXX]

When I go to work today I'm going to make a new mock up box. I'm going to try going 17 on height and an extra half inch on both length and width. If it fits I will get 2.99 net at 35hz with 13 of port area. I'd like 16 but I would be sacrificing more cubes. One more question, what it be better to get the port area to 16 and loose a little cu es or keep the cubes with less port area lime I ha e it? TBA ks for all your feedback btw. I've also been considering an scv1500 instead of the 2000 because I also have a component amp I only ha e big 3 plus a aux battery, which I also haven't ordered yet

 

[ancorp 10+ year member]

I'd leave it at 13" per cube as 3 net is the lowest I'd ever go for a SA15 for daily. Make sure you round every edge and flare it out on both ends as much as possible to make it more efficient.

 

[Jeffdachef 5,000+ posts]

I have a 15.5 cube trunk its just the trunk opening is so friggin small. If this doesn't work I may look in into building something in place I the trunk, I didn't want to loose access to the spare which I why I decided not to for now. I also need to mention that although I've had a system in almost every car I've owned this I the first one im trying to build so particular and by factory specs. I've always just thrown what I could get into a trunk. My last system was two audiobahn 15s sealed on a jbl1200, and it was decent to me. I hope what im building with the boxes I've designed thus far will blow that away

it wont blow away anything. too little airspace man. Fk the spare tire, just get a tire repair kit instead along with pump.

 

[CeleronXXX]

I messed around in the maintenance shop like I had planned today. I ended up with 3.01 net with 14.25 of port area. Better than I thought, and its within specs so I hoping it will sound decent on 1000rms a piece. I also still have room for two batteries. I haven't even purchased the woofers yet, If an XFl would be better suited for my airspace and planned amp I could go that route, but the sa's seemed like a good option to me.

 

[Jeffdachef 5,000+ posts]

Might want to look into a dayton ho 15, they work well in 2.5 to 3.0 cubes