So last year I had 1 12w7 in a 2.5 cu foot box tuned to 30 hz and absoluey loved it and how it really killed the lows
Now I have a second one and they each have there own jl 1000 thry will be run off of ( and I.have all the electrical upgrades to do so)
The largest box I can fit tho will be 4.25 cubic feet for the two.
My questions are: A- would it be better to have it a single chamber at 4.25 cu feet or make it two chambers at around 2 cu feet each? These measurements areafter the port is subtracted.
B- is 2 cu feet per sub enough airspace and will it sound as deep at the same tuning frequency as the 2.5 cu foot box?
single chamber will allow a little more airspace. and yes 2 cu ft per sub is fine especially with the space shared. keep the same low tuning and it will be crazy loud. you have good alt and or batts to properly power those amps? thats quite a bit of money invested in subs and amps. you want to make sure you can use them properly
Or if you can do a single 6 in aero port that would be better Or even better yet if you can do a slot port with 1.75 cu ft I would say that's your best bet for output and getting low and even tune a little higher like 32 to 34 that could save some space and still get very low
Sorry I wasn't very clear yes 1.75 per sub that's after all displacements including subs port and bracing So gross the box will be bigger than 3.25 cu ft it really depends on how much port you want and of course lower tuning needs more port
"A- would it be better to have it a single chamber at 4.25 cu feet or make it two chambers at around 2 cu feet each? These measurements areafter the port is subtracted."
If your tight on space, go with just a common chamber as dual will require a bit more volume. Depending on your vehicle and power running 4.25-4.5 cubes would work very well.
B- is 2 cu feet per sub enough airspace and will it sound as deep at the same tuning frequency as the 2.5 cu foot box?
Simple answer is yes. If you keep the tuning right around 30hz (which is perfect for W7's imo) you will still get excellent lows. Let me know if you need any help with the build or design man.
If space is something that you are tight on, I wouldn't look past using aero's. The downside is is that Aero's (precision ports) can get quite spendy if you are on a tight budget. But they help output ans save a ton of space.
I had Dustin build me an enclosure for my 12w7 a while back and it was 2.0 cubic feet after all displacements tuned at 32 Hz. I was happy with the output and low end the enclosure gave me. You were running a single w7 yourself and now you're going to be running two. Doubling your displacement by running another sub is going to give you a huge increase in output. So even though the box might not be as large as you had hoped for, you're still going to have a great set up. If you're able to give the subs 1.75 cubes a piece, they should do just fine. You're also doubling your power, so that too is going to give you a big increase in output as well.
What are the actual measurements you have to work with in-cabin to build the box?
If you go w/ a common chamber box, depending on the actual net volume the subs will actually react like they are in a larger chamber than they 'see'. Acoustics of a common chamber change slightly. For instance, your subs may react as-if they are in as much as a 15% larger chamber than the actual net volume.
Properly braced and given the same signal (strap your amps)....a common chamber can save a little space and help w/ in-cabin acoustics.
I've always wondered if putting a wall between the subs that goes just past the basket gives a better performance...I forget where i seen that at, but it made sense to me,lol.I'd like to know.
Using some box building software I have come up with these 2 boxes:
SLOT PORT - Box is 16x16x39 - Net volume is 3.6 cu feet (single chamber) - Slot Port is 14.5x2.5x24 (tuned to 30hz) (10.15 sq inches of port per cu foot)
AERO PORT - Box is 17x16x38 - net vloume is 4 cu feet (single chamber) - 6" flared aero port about 14" long to tune it to 32hz (7.05 sq" of port per foot.
