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nismos14
12-14-2006, 11:11 AM
I have a box 33 wide by 13 high by 11 deep. The port is 4 inch x 15. Can someone please assist me in figuring out what this port is tuned to? I appreciate any responses.

matt_martin87
12-14-2006, 11:18 AM
I assume it is a 4" round port at a length of 15".

I'm getting approx. 34hz. Someone correct me if I'm wrong.

nismos14
12-14-2006, 12:28 PM
Yep 4 inch round. Ok I kept getting calculations between 30 - 32, but the main issue was some places were saynig that a shorter port like 8.9" would give me the 30 hz tuning.. that threw me for a loop.

nismos14
12-15-2006, 09:14 AM
Anyone else?

evan
12-15-2006, 02:01 PM
If you guys are using WinISD to check, how do you take the effects of the different speakers out of the equation? I'm not sure how to start a project without having to choose a speaker first, and once I've chosen a speaker it effects the way the numbers are calculated.

iamamp3pimp
12-15-2006, 02:06 PM
no...it effects the graphs...not the numbers

iamamp3pimp
12-15-2006, 02:10 PM
32 HZ before sub displacement.....1.956 cubes @ 31.96 hz

evan
12-15-2006, 02:22 PM
no...it effects the graphs...not the numbers

32 HZ before sub displacement.....1.956 cubes @ 31.96 hz

So did you find the volume of the box and subtracted the volume of the port to get 1.956? Doesn't the program account for the displacement of the sub also?

iamamp3pimp
12-15-2006, 03:24 PM
yes thats how i got it...the volume of the port and 1/4 inch to account fopr the PVC displacement.


thats assuming its 1/8th thinwall.

rpfuror
12-15-2006, 03:28 PM
If assume .08 cu/ft displament for the driver and that it is a 4.20 OD port I get net box volume = 1.89 cu/ft @ 22.40Hz

nismos14
12-15-2006, 07:24 PM
The driver is a DLS SP12, magnet is pretty large. http://www.dlsamerica.com/pdf/manrultsub3.pdf thats the manual for it.

So i could potentially be tuned as low as 22.4 hz?! God this is confusing. So With the way its tuned, if I was running a 30hz ssf would that be a bad thing?

Immacomputer
12-15-2006, 07:52 PM
It's no where near 22hz. I have a net volume of 1.8 cubic feet after port, sub, and wood thickness. The tuning I came to was 32hz.

nismos14
12-15-2006, 08:24 PM
Thats what I get! Maybe he meant 32.4.

rpfuror
12-15-2006, 08:56 PM
edit... actually, u guys helped me with my math.. I had the wrong number pluged into my equations.

yes = 32.4with 1.8cu/ft net;)