BTL 18 Box Design?

[holley2346 6]

Was wondering if anyone on here could offer me a reaonable design for a btl 18 for free. I have a guy at the car audio forums that has always done mine for a small fee (they are reasonable).

BTL 18

Tuned to ~30 hz.

~ 5-6 feet ^3

48 inches wide... and max of 24 inches high.

[Joker 0]

My design is about what your looking for , I am also going to be running a 18" BTL .

My goal was 6ft^3 with all displacement's tuned at 30Hz , slot port . Sub up on top and port back .

Box is designed to fit in my hatchback car so if the dimension's don't work with your space then it can be modified .

Outside dimension's 17" H x 29" W x 34" D . Using .75" MDF I get an internal volume of 8.02ft^3 .

Slot port of 5.5" W x 15.5" H = 85.25sq in port area

Total port length is 32.75" , port board going into the box is 23", plus the .75" MDF face = 23.75" board length .

Without the sub displacement this box is 6.39ft^3 tuned to 29.83Hz .

With the sub the box is 6.13ft^ tuned to 30.47Hz .

The top would be double baffled making the overall outside height 17.75" .

The extra bit of volume provided by the sub cut opening with 2 baffle's of 1.5" H and 16.750" sub cut diameter make's the boxe's final volume ~

6.15ft^3 tuned to 30Hz , 85.25sq in port area (13.87sq in per cuft )

The total port length to slot port internal width ratio is 5.95:1 .

Cut Sheet and assemble in this order ~

Bottom - 29" W x 34" D

Back - 15.5" H x 29" W

Left side - 15.5" H x 33.25" D ( port side )

Right side - 15.5" H x 32.5" D

Front - 15.5" H x 22.75" W

Port - 15.5" H x 23" D

Top - 29" W x 34" D ( need 2 of these with a 16.750" sub cut on both )

I am going to be adding some internal bracing with wooded dowel rods bracing the front to back , side to side , top to bottom , side to the port etc .

[holley2346 6]

How could I change the dimensions to make it 48" wide?

Thanks

[indytrucks 1]

http://reaudio.com/speaker_box/LPort_Box_Calc.html

Play away.

[holley2346 6]

Will it be ok if I set the port length 2 to 0 ?

[indytrucks 1]

Yeah. Just put like .0 or something. You can change the width of it. Let me know what you end up at.

[holley2346 6]

Box Width : 48 inches

Box Height : 15 inches

Depth : 20 inches

Wood Thickness is 1/2 inch I believe.... I'm not at the shop

Port Width : 5 inches

Port Length 2 : 6 inches

Will this work with the sub up mounted on the far right of the box?

[ADK 0]

you definatley need the wood thickness for a BTL to be ateast .75 or even an inhc along with bracing and baffles.

[holley2346 6]

I am fairly sure it is 3/4..... my memory fails me. I have no idea why I would buy 1/2. It would be braced very nicely.

Therefore height gets bumped up to 16 inches.

Edited April 3, 2009 by holley2346

[indytrucks 1]

Um, I would go with two layers of the 1/2" if I was you. So one inch total. Might need to reevaluate your plans.

Edit: Nevermind. If its 3/4 with the 16" height should work great. Right at 30Hz. Just under 6ft^3 after displacement. Aint nothin to it but to do it now.

Edited April 3, 2009 by indytrucks

[holley2346 6]

The wood has already been purchased...... 3/4 inch mdf. Everyone dissed my 5/8 particle board box for 2 18 inch bl's, and after taking it out last week I noticed it had not cracked, come apart, or shown any signs of stress at all! At least if it blows apart I can show you an awesome box exploding video.

But will that work correctly if I mount the sub up on the fa right of the box?

Thanks

edit: alright, going to start on it tomorrow afternoon! sub comes in tuesday! :)

Edited April 3, 2009 by holley2346

[indytrucks 1]

Looking forward to it.