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orphe
09-05-2006, 01:00 AM
I built a box about a week ago but I dont know if I calculated the tuning freqency right.
Box details

I have the port fireing up.

total driver displacement is about .174 cu ft

the external dimentions
40 *18 *16 = 6.67 cu ft

internal dimentions
38.5 * 16.5 * 14.5 = 5.33 cu ft

port area 3.5 * 16.5 * 13

Any ideia wht this is tuned to? :confused:

tank65
09-05-2006, 01:48 AM
http://www.carstereo.com/help2/Articles.cfm?id=31

that should help i dont really know though

jeepintn
09-05-2006, 01:52 AM
if the internal deminsions u gave are including the port... its about 43 hz.. if they are not including the port... about 41 hz

xluben
09-05-2006, 09:04 AM
you don't want the port ending that close to the back wall.

but that tuning is right around what jeepintn posted.

Trixter
09-05-2006, 02:01 PM
you don't want the port ending that close to the back wall.

true....it should be no closer to the back wall then it is wide.

orphe
09-05-2006, 11:18 PM
Is there any way I could change the tuning to 30-35 HZ?

xluben
09-05-2006, 11:19 PM
90 degree turn in the port!

this looks about right:

http://www.subwoofertools.com/forum/ported-box.asp?Ew=40&Eh=18&Dia=6&Xmax=15&Vd=.085&NumW=2&Vb=4.25&Fb=35&Qts=&Vas=&Fs=&CE=0