12" BL enclosure

[SKiN 0]

I haven't ever designed a ported box before, but I did alot of reading and sat here for a few hours and came up with a design for my enclosure. You guys wanna check and see if I did it correctly?

will be using 3/4" MDF.

Outer dimensions: 29.5" width

15" height

15" depth

Inner dimensions: 28" width

13.5" height

13.5" depth

Volume = 28 * 13.5 * 13.5 = 5103 cubic inches

convert that to cu.ft 5103 / 1728 = 2.95 cu.ft before sub/port displacement

Port dimensions (which I hope are correct): 2" width

13.5" height

20.53" length

Port volume = 2 * 13.5 * 20.53 = 554.31 cu.in

convert to cu.ft 554.31 / 1728 = .32 cu.ft

so... 2.95 minus .32 minus .15 (sub displacement) = 2.48 cu.ft

I am looking for a total of 2.5 cu.ft (after sub/port displacments) tuned to 33Hz.

Does that look correct to you guys? If not... what do I need to change?

thank you

[shizzzon 461]

pretty good for your first try. There's only 1 thing you forgot to calculate displacement-wise, you're gonna say "OH yea!" on this one, hehe.

The port displacement you say is 2" wide, 13.5" high, 20.5" deep

this is a slot port i take it?

If it is, then 2 walls of the enclosure will be used for the port as well.

Usually, the floor and the side wall, but since your port equals the height of your enclosure, then the top will also be used for your port. The only remaining side left is the port wall... which is 0.75" thick.

So the port displacement of 2.75" wide x 13.5" high x 20.5" deep = 0.44 cu ft minus .15 for sub displacement equaling -

2.31 cu ft internal.

[SKiN 0]

pretty good for your first try. There's only 1 thing you forgot to calculate displacement-wise, you're gonna say "OH yea!" on this one, hehe.

The port displacement you say is 2" wide, 13.5" high, 20.5" deep

this is a slot port i take it?

If it is, then 2 walls of the enclosure will be used for the port as well.

Usually, the floor and the side wall, but since your port equals the height of your enclosure, then the top will also be used for your port. The only remaining side left is the port wall... which is 0.75" thick.

So the port displacement of 2.75" wide x 13.5" high x 20.5" deep = 0.44 cu ft minus .15 for sub displacement equaling -

2.31 cu ft internal.

OH YEA!!! i forgot that lil bugger!!

now does that mean i have to start allover or is what i have now alright? so basically instead of "thinking" i have a 2.5 cu ft box tuned to 33 hz, i have a 2.3 cu ft box tuned to 33 hz?

one last question... for a double baffle... if i add an additional 3/4 inch to the depth of the enclosure... that will make everything the same as it is now right?

thank you very much shizzzon :beer: for you

Edited February 10, 2008 by SKiN666

[shizzzon 461]

just add a another sheet of wood to the outside of the box, that will not change anything.

This is what i have for you based on graphing software for this box-

2.3 cu ft using that port length-

box will be tuned to 35hz.

And i made a mistake of my own!

the displacement of the port actually is - 2.75" x 13.5" x 19.75" (0.75" thick for baffle)

If you plan on adding another layer, subtract another 0.75" from the INTERNAL port length.

Since the baffle counts as part of port length when it exits, 2 layers would be 1.5" worth of port.

If you need any more help, let us know

[SKiN 0]

this is what i drew in cad really quick

scratch that... what i drew in cad came up complete chit when i posted it on here... was way too small

this is driving me nuts

Edited February 10, 2008 by SKiN666