Ported Enclosure

[Rogers]

ok so since i traded my type s's for 2 type r's im going to be buying 2 more and i might as well get my box design out of the way...

an eclosure for 4 12" type r's

so the type r's need 1.3cuft net each... so thats 5.2 net alltogether

im going to do (4) 4" round ports x 18" long = .44cuft displacement

should be 35ish hz

the driver displacement is .07cuft per sub = .28cuft

so i end up with a total displacement = .72cuft displacement

so my gross enclosure volume needs to be = 5.9cuft

so im going to do subs up ports back again...

so im thinking my demensions will be... 33"wide x 15"tall(double baffle) x 27" long

making my internal deminsions 31.5"wide x 12.75"tall x 25.5"long =5.92 gross

let me know if im off.....

[bkolfo4]

You got it. . .

[Rogers]

You got it. . .

you taught me man....thanks! i havent decided if im going with this enclosure or if im going to do a slotvent, if i do a slotvent im not sure how wide to make my vent...

[bkolfo4]

You will see the general rule 12-16 sqin of port per cuft of enclosure. This normally works out, but port area is really determined by the air velocity moving through the port.

If I have a 7 cuft box for an 18" driver and I put in a low excursion driver and a 500 watt amp, that is not going to require as much port area as an 18" BTL on 4000 watts. . .Not that it will hurt to have more port area on the low power setup, it is just not a must if space is an issue.

I use this for my box designs:

http://www.carstereo.com/help2/Articles.cfm?id=31

Slot ports are as easy to calculate as round - same method - just watch out when the length gets the port wall too close to the back wall.

Brian