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[acarmody]

A 3 cubic foot box, all constructed with 1" MDF. With a slot port thats 1.5" wide, 14" high, at 35hz, which equals 11.6172" length, which equals 0.2353 cubic foot displacement including 1" MDF wall.

The Subwoofer specs say the 15" woofer has 0.14 cubic foot displacement.

So total displacement is 3 + 0.14 + 0.2353 = 3.375 cubic feet.

A box that has outside dimensions of 34" x 16" (height) x 15"= 3.37 cubic feet.

So new box will need to be 34" long, 16" high, and 15" deep. Now remember these are outside dimensions using 1" thick material.

Make the bottom and top pieces 34" x 15".
Make the sides 14" x 15".
And the front is 30.5" x 14" (because of port) and the back is 32" x 14".

 

[MattyC]

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[MattyC]

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[acarmody]

According to the specs of the sub, the actual cutout for the sub is only 14.25", so it should still work.

You said earlier you only have 420mm of height to play with, well thats only 16.5" so you wouldn't be able to build a 17" tall box.

I'd wait till someone else confirms my specs because I'm not a professional box builder.

 

[holdenboy]

Yep acarmody is pretty much right on the money i think......although the slot port will need to be wider than 1.5", a general rule of thumb is to have a height to width ratio of no greater than 1:8, otherwise the port turns into a large gap that acts like a leak in the box, not a port.

If you want a massive amount of bass, ive found the Digital Designs enclosures to go hard.....this is one ive used before with alot of success, i realise you only have 420mm to work with and not 430mm.......so just make it 420mm and add a little extra to the port depth (around 30mm is fine).

 

[MattyC]

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[Fun_Bucket]

Just thinking a 3 cubic foot box is more of an SPL box. Maybe a 2.5 cubic foot box would be more suitable. The one I posted up should work but I wouldn't be pushing the sub all the time. Its a 1000wrms woofer so I would NOT put more than 1000wrms into it. Maybe even tune the amp for 900wrms.

Just quickly, out of interest, why would you not want to run that much power, or more? my only ported enclusre was underpowered by about 200RMS, but with the rest of my sealed enclosure's, i've always ran a considerable amount more power into them, that their rated input.

Is it that it's bad for the sub in a ported enclusure to be fed any extra power? Is there not as much need for extra head room when porting due to the extra effeciency?

 

[holdenboy]

Generally, a big ported box will lower the subs power handing......definately when playing under the tuning frequency. But on the other hand, a smaller box will handle more power......but it will be harder to get a lower tuning frequency (can i just say "F3" from now on haha) in a smaller box.

Still, everyone has to remember that 90% of amp ratings are done with two parameters that arent accurate in the real world, one is the voltage the power is taken at (mostly 14.4v - how many people have 14.4v when the system is cranking?) and the second is its taken with a non-reactive load (i.e. 2 ohms, as soon as you turn the volume knob i can guarantee your speakers / subs dont stay at 2 ohms - more like double that).
But it works both ways, sub manufacturers rate their products in the best case scenario......to get the most possible wrms rating, although IMO the amps output power is going to be further away (lower) than the subs rating is.

Sorry for the rant

 

[bezz]

lol why do car audio guys hate the metric system so much?

 

[holdenboy]

because its just easier Subs / speakers are measured in inches so why not just measure everything else like that?

Why are you such a pain bezz???

:banstick:


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