Need Help, Ported Box Build For Sa12 In a 2010 Cobalt

[john253a]

you wont regret the low tune, unless you want to show off,

dont get me wrong this sub will still be loud but ti will yeald a flatter response @ 26-27hz then 30-33

but 33-35hz will be a lot louder,

best bet i can say before you build is try to lission to someone setup with same sub and see what they are tuned to,

and tune it to what you think will best suit your needs

[Hellbilly429]

I wish I had that option John but their isn't even a sundown dealer in my area, let alone any real pro audio place, any place I have ever walked into just tells me what their favorite brand is and how it beats everything else and how cool their stuff sounds with their prefabbed sealed boxes... God forbid these people even have unbiased knowledge of car audio and any knowledge of custom enclosures...

Also, I don't know if it's possible at all but I was looking to make something that can compare to my neighbor's JLW7 in a sealed box that was custom made for his camaro, he's always rolling in and out of here blasting shit like he's billy badass and how I would love to roll through here and be like what now? I didn't spend half as much on my system as you did and mine sounds as good if not better! I know, just a pipe dream of mine...

[JWIDE]

Remove your weather seal from your trunk opening and that should give you another 1/2"-3/4" of opening to help get the box in the trunk

[412Mark]

I have a two door Cobalt that I am starting to make a box for. I have found it easy to take out the fold down part of the back seats. with them out of the way, it should be very easy to slide a nice big box in there. I think I can get atleast 6 cubes net and 5 cubes gross for two 12s.

[CleanSierra]

I have a two door Cobalt that I am starting to make a box for. I have found it easy to take out the fold down part of the back seats. with them out of the way, it should be very easy to slide a nice big box in there. I think I can get atleast 6 cubes net and 5 cubes gross for two 12s.

I think you have it backwards. Net is after displacements, gross is before. So 6 gross, 5 net...

[Hellbilly429]

Hmm, I will have to take that into consideration. I really didn't feel like having to take the back seat out to put a box in there but if it comes down to it I will. I am also considerring what I could do to get the bass from the trunk to the cabin without leaving the back seat down in case I have passengers, but I do still have a loan on this car so don't want to cut it up too much... lol

[412Mark]

The back seat are very easy. No screws at all. They have a clip to the left and to the right. Then they both have a whole that a post slides into in the middle. I checked it out on mine and it took less than 5 to take them out and put them back in.

[412Mark]

@CleanSierra I did know that I have it written down right on my plans. Just wrote it too quick without thinking and proof reading.

[Hellbilly429]

Gotcha, appreciate the pointers, I haven't looked into it too hard to be honest. I have also placed a 1/2" piece of plywood underneath the carpet that I cut and stapled and ran weatherstripping around the edges so the subs have a solid platform to sit on and to help keep the vibration down.

[CleanSierra]

I didn't see you mention anywhere what you plan on powering this Sundown with. While it is nice to see what numbers will work to fit into your trunk, it's also nice to build the enclosure to match the power you'll throw at the sub. 2 cubes is a good volume to shoot for if you're just throwing the suggested 600W at it. If 1000W are being considered(which need to be a CLEAN, unclipped 1000W, maybe drop volume to 1.75 cubic feet. I also disagree tuning below 30. I know Jon has been very successful with tuning his SA8s to like 28Hz, but I'd stick with 33-35 for a daily tune if I were you. I'd shoot for a port area of no more than 15 sq inches per cubic foot as well. 12-15 would be a good range.