Ok so here's the deal. This is my wall design for my two 18in. fully loaded btls that will be running 3000rms a piece. I have never done a wall build before so I'm hoping i somewhat got it. EVERYTHING is double baffled 3/4in. mdf . In the 1st picture showing the front plate it looks double baffled its only supposed to be single " which i just fixed and im to lazy to take and upload another picture" due to the fact that there will be another front vanity plate to go around the curves in the car all nice and snugly.

The box is , 15.7341 ft³ BEFORE DISPLACEMENT

15.2141 ft* after sub displacement displacement

port is 6 inches in height

width is 29.224 inches

length is 4.79

tuned to 32hz.. does this sound right to you?. port seems a bit off to me, but then again i've never worked with some subs on the scale of these.

Also i know this is going to sound stupid but due you factor in port displacement and take it from the volume of the box? etc etc.

Edited May 26, 201015 yr by imthebombticktick

I'm no SPL guy but it looks like a good design. You may want to put the port along the driver's side of your vehicle and then stagger your woofers diagonal to fit.

Always account for all port, speaker and bracing displacement when calculating internal volume.

I'm no SPL guy but it looks like a good design. You may want to put the port along the driver's side of your vehicle and then stagger your woofers diagonal to fit.

Always account for all port, speaker and bracing displacement when calculating internal volume.

I would do that type of design but im trying to keep my back seats. Thats why its got that slant in the back so it will go along with the structure of the roof.

About the port displacement though i'm having a brain fart its almost 5am. When i go to calculate my port length i have to put in the width/hight/enclosure volume. How would i find the port displacement it just seems like a infinite loop to me.

I also will be throwing in a couple of 1in. wooden dowels coated in fiberglass to help with bracing but i think the double baffle all around should be good with a good amount of glue and screws.

Look under the BTL specs on the Fi website it's probably around .20ft^3!

Look under the BTL specs on the Fi website it's probably around .20ft^3!

unless we are misunderstanding each other, all i see for displacement is for the subwoofers which is already factored in.

Fs: 31.9 Hz | 31.1 Hz

Re: 0.7 Ohms/coil | 1.4 Ohms/coil

Qms: 6.26 | 6.42

Qes: .26 | .24

Qts: .24 | .023

Mms: 313g | 329g

Sd: 1210cm^2 | 1210cm^2

Vas: 163.1 l | 163.1 l

Spl: 94.9dB 1W/1m | 94.9dB 1W/1m

Bl: 18.3 N/A | 27.2 N/A

Xmax: 28mm * | 28mm *

Rms: 2000W * | 2000W *

Sealed box: N/A cuft | N/A cuft

Ported box: 5-10cuft | 5-10cuft

Sub OD: 18.500” | 18.500”

Cut ID: 16.750” | 16.750”

Mounting depth: 10.250” | 10.250”

Displacement: 0.26cuft | 0.26cuft

My bad, yes subtract the port displacement from the internal volume! Port width x height x length = port volume.

My bad, yes subtract the port displacement from the internal volume! Port width x height x length = port volume.

Here is where im confused.

i used PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES to calculate the port. i put in my freq. enclosure volume. then my width/height of port to get the length.

So if enclosure volume has to do with the length of the port and port displacement has to do with the volume of the enclosure.. WTF its just a loop isn't it? or am i doing something wrong

Try calculating with this .... Enclosure Volume Calculator (EVC)

Scroll down for the port volume and put in your dimensions

Try calculating with this .... Enclosure Volume Calculator (EVC)

Scroll down for the port volume and put in your dimensions

doesnt seem like i can due to my box having those weird angles

on a side note my port volume is 839.898

also i dont think im getting what im trying to say across here.

Edited May 26, 201015 yr by imthebombticktick

My bad, yes subtract the port displacement from the internal volume! Port width x height x length = port volume.

Here is where im confused.

i used PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES to calculate the port. i put in my freq. enclosure volume. then my width/height of port to get the length.

So if enclosure volume has to do with the length of the port and port displacement has to do with the volume of the enclosure.. WTF its just a loop isn't it? or am i doing something wrong

No!

Enclosure has nothing to do with port length. Port length is your tuning frequency. Port displacement has to be subtracted from total enclosure volume to get an accurate internal volume.

You maybe thinking of port area which is port width x port height (6" x 29.224) = 175.344in^2 of port area. And the 4.79" length will give you your tuning 32hz frequency.

ok thank you, sorry for the hassle its been a long day/night getting this right.

i greatly appreciate the help and information.

So its 14.7281 after sub/port displacement. Seems good to me, on my post a bit back of one of my quick mockups someone said

"Are you sure you want to go that large with all that power? Usually the enclosure is smaller if overpowering" when my original plan was to due 18-20cf. so this turned out good!

Just an FYI, you're not making a slot port box, your tuning is way off. Click the slot port option to off and then recalculate. It should be 19.4" long.

Just an FYI, you're not making a slot port box, your tuning is way off. Click the slot port option to off and then recalculate. It should be 19.4" long.

man...i feel stupid lol.