So while waiting for my sub to arrive I've been messing around in sketchup, which I just learned to use. This is only my second design but I think it's pretty good. Let me know what you guys think. Only thing I'm weary about is how the sub will be right in front of where the port begins. Is this a problem? Maybe I can go narrower on the port and make it longer...

Edit: Forgot to mention it's for a Fi Q 12". Also not sure of the port displacement. 3.43 would probably make more sense for a sealed enclosure...how do I take into account the port?

3.43 cu. ft. @ 31 Hz

Edited January 24, 201114 yr by sonicsaiyan3

Too big for one 12. My opinion.

I'm an idiot. Misread rec specs as 3.5 instead of 2.5. Gonna redo the design now.

Take two...

2.39 cu. ft. @ 31 hz

Looks good, I'd move that sub cutout to the right though. It looks like the box isn't very deep and it would be pretty close to the port opening.

Something like this?

Yeah, I know it's not visually appealing, but it makes better use of the space you're putting it in.

Okay, here's the final design. Gonna pick up supplies tomorrow and get to work.

2.40 cu. ft. @ 32 Hz

how much port area per cube?

I have no idea...how do I find it?

From the last design I see: 2.5" for port width and 12.5" for port height. 2.5*12.5 = 32.25 square inches of port area.

if you stuck by the 12"-16" rule, then your in between 28.8" and 38.4" (so it looks like it'll be fine, but I'm no box builder)

Whats the depth of the box?

Whats the depth of the box?

Dimensions are 28 x 14 x 14

Whats the depth of the box?

Dimensions are 28 x 14 x 14

Thats what I thought. While your gross volume is 2.4ft^3 as soon as you put the port, and driver in the volume and tunning changes. Your box will end up being 1.51ft^3 @ ~38hz

Yeah, you need to use a predetermined net volume to find the needed length for the port. Then find the volume it's going to take up, along with your sub/bracing, and add that to the volume you used to find the port length. This will give you the needed gross volume of the box. Then just plug and chug different dimensions until you find ones that work(or close enough so you can add some more bracing, 45's, etc, to take up a little more volume if needed).

Easiest way for me to do it is have two dimensions set in stone, and just adjust the third.

Edited January 26, 201114 yr by RAM_Designs

Makes sense, I think I got it now. I misinterpreted port length for physical port length, also wasn't taking port displacement into account.

3.49 cu. ft. before displacement

2.26 cu. ft. after port & sub displacement

Tuned to 32.05 Hz

Port area per cubic foot - 14.38 sq. in.

Edited January 26, 201114 yr by sonicsaiyan3

Unless you have bracing I don't know about your taking to much volume out somewhere.

Big volume = 10.625 * 31.125 * 12.5 = 4133.7890625 / 1728 = 2.39 ft^3

Small volume = 3.375 * 14.3125 * 12.5 = 603.80859375 / 1728 = 0.349 ft^3

2.39 + .349 = 2.739 ft^3 - .16 sub displacement = 2.579 ft^3 which gives you a tune of ~30hz

^Not sure I'm understanding what you mean. Are you referring to the last design?

Yes, you can split the shapes in the box to separate shapes to figure internal volume, like I did.

(Big volume = 10.625 * 31.125 * 12.5 = 4133.7890625 / 1728 = 2.39 ft^3) Where the sub is mounted.

(Small volume = 3.375 * 14.3125 * 12.5 = 603.80859375 / 1728 = 0.349 ft^3) Area to the left of the port

(2.39 + .349 = 2.739 ft^3 - .16 sub displacement = 2.579 ft^3 which gives you a tune of ~30hz) Added together minus sub displacement.

You can / must trust Bromo : he designs fantastic boxes.

The last one he designed for me is...fantastic !!! The sub is a monster (a 12" fi btl), but the box plays a very big part in the sound.

I feel like my sub loves this box !!!

Asked him to fab me up a box design. Can't wait till I can finally build this thing. Sub comes in today.

Edited January 26, 201114 yr by sonicsaiyan3

here's what my box looks like at 2.5 cubes tuned to 33hz

Edited January 26, 201114 yr by Elton