Box for 2 sa 12's feed back

[Nealon14]

hey i was hoping some of you experienced guys in car audio could take a look at the box design i been working on for 2 sa 12's on 750 watts rms each. give me any feed back so i can fix anything now because i am going to start building over the spring break. it is for a 4 door sedan with seats that cannot be folded down. i am using 2 4" aero ports about 11.7inches in length (flared on both ends) one for each chamber tuning is about 34 hertz. outside box dimensions 31 x 13.5 x 25. i am building a separate chamber box with each chamber 2.06ft^3 with aero ports, bracing and sub displacement included.

i am using 1.5" hardwood dowels and 3/4" MDF here is a link to the dowels and some pictures of the box

http://www.homedepot.com/p/Waddell-1-1-2-in-x-36-in-Round-Hardwood-Dowel-6352U/203706846?N=5yc1vZaqifZ1z11cot

[john253a]

Do a single chamber so they have a shared/ common air space

As for port 1x 4" each will not cut it

You'll either need 2x 6" or 4x 4" ports

With either set up you'll want them 22-27" long

In 4net

And being in a trunk car

Don't fire the subs up fire them the same way as the port

And for max sound in cab

Don't worry about seats not go down

Still seal it off and do both fwd

And if you do both fwd you won't fit aero ports in you'll need to do a slot port

[Nealon14]

wow thanks for all the help john i really appreciate it. one problem i have is that i bought an sa 12 a few months ago and i bought a newer one recently. therefore i need a new box and i didnt want to do shared because i am scared it will mess up my newer sub. would it be ok to put an old sub and a brand new one together like that in the same chamber? on top of that i already bought 2 4'' aero ports. i also dont have the skills to do 45 corners or flared slotted ports thats why i strayed from slotted. if it will make a significant difference doing subs and port on the same face i will have to do a slot port.

[john253a]

Are they the psp ports?

In that case stick with separate chambers

But leave the ports at the full 17" including flare (approx 30hz)

Idd still try and run all the same direction

[john253a]

And if you can't move the port opening as far away from the sub as possible to refuse unloading

[Nealon14]

yeah they are the psp ports the price was great like 14 bucks for one. ok so i wont cut the port lenhths to 12 inches i will just tape together the port parts and see how that works out. i am going to use clear packaging tape hopefully it holds up. how far does the port inside need to be from the wooffer? because if i use the port at 17 inches the sub will be ontop of the port. if i use the original 12 inches i think the opening for the port is like 4 inches from the subs magnet.

[thefourth]

IMO all that bracing is a bit overkill

[Nealon14]

so if i was to put the ports on the most bottom left and right spots on the box it will be louder than putting it in the center bottom?

[Guest]

IMO all that bracing is a bit overkill

you can never have too much bracing lol.

[Nealon14]

lol i wanted to add alot of bracing because i read on a few websites that it is very important so the box walls wont flex and create problems. i still have to figure out how i am going to put all this together with the bracing. i never built a box with bracing before