redsox98

Hey Guys,
This is my 1st post here and I was wondering if someone can help me with my question.
For the first time I looking into making my own box! I would like to try to make a Ported sub box. I'm going to get the mdf wood cut on friday (March 11).
I have 2 Alpine SWR-1243D 12" R Series 1800 Watt Subwoofer with a JL Audio J2 1000.1 1000 Watt Class D Subwoofer Amplifier.
I was wondering if you could give me the directions to making a box.
I'm looking to tune it to about 30-35 hz.
What sized holes would I have to make to get my subs in there snug?
The biggest I could make my box to fit in the very back of my trunk is 33" in width, 14.5" in height and 15" in depth.
Thanks in advance.
Looking forward to your response.

Denonite

iTrader: (1)

using your max dimensions will give you about 3.2 cubes net using .75" mdf. I recommend a single port that is 13" tall x 2.5" wide x 28" long which will reduce your net volume to 2.6 cubes and subtract .2 cubes for the sub's displacement will yield 2.4 cubes net internal volume. The tuning will be approx. 33.3 hz. If you add 1 pound of polyfill/cubic foot internal or about 2.5 pounds total, then you can reduce the port length to 21" for the same tuning as the polyfill will create a virtual volume of approx 3.0 cubic feet internal (approx. 25% volume gain with that density of polyfill). With that port size and box volume your port air velocity will be under 30m/s at full power (1000 watts), so no noticeable port noise at full output, group delay, frequency response, is nice and smooth with a typical boost in bass between 25-80hz versus a sealed system, and cone excursion using a subsonic (infrasonic) filter set at 20hz (1st order or higher is fine..6db/oct or greater) will prevent the subs from exceeding 18mm xmax at full power (1000 watts) ...subs are rated for 20-21mm xmax, so very little to no risk of mechanical damage due to over excursion. If you can, try to put a slight angle on the front or rear baffle to prevent standing waves, use the polyfill, and make sure you brace the box internall using strips of wood crossbracing the walls. When done, be prepared for loud, clean, shake your fillings loose bass!! and the hole sizes are listed in the manual.

SPLACCENT

Ive built over 10 boxes for my old type r's. I would personally recommend at LEAST 2.2 cubes each to begin with. they do not require a big port as well. Try tuning around 28hz first, you can always cut your port shorter to raise the tuning. With the space you have id build a box 33wide 14.5high and 13 depth, with a port 1.75 wide 28.75inches long.

Denonite

iTrader: (1)

^^that would be great if size is not an issue...but given the op's max box size," The biggest I could make my box to fit in the very back of my trunk is 33" in width, 14.5" in height and 15" in depth", 2.2 each would be impossible. OP if you can spare 33 x 14.5 x 26..sure go for it, bigger box, bigger port=more efficient, louder, deeper bass!

SPLACCENT

Id only run one 12 in the box i mentioned.

Lord Huggington

iTrader: (1)

I'd tune it to 35 Hz with enough port area just incase you want to stick some MDF in the port to bring the tune down to 30 Hz... if that's even possible.