help figuring out tuning frequency

[orphe 10+ year member]

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? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

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[tank65 10+ year member]

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

that should help i dont really know though

 

[jeepintn 10+ year member]

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 10+ year member]

you don't want the port ending that close to the back wall.

but that tuning is right around what jeepintn posted.

 

[Trixter 10+ year member]

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 10+ year member]

Is there any way I could change the tuning to 30-35 HZ?

 

[xluben 10+ year member]

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