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View Full Version : Quick Port Question Please HElp



NoPh33rRaCiNg
05-18-2007, 05:27 PM
What happens to the tuning of the box when the first port width area (the width of the port area where the air exiting the box) is about an inche wider than the 2nd port width more toward the inside of the box.

im using this diagram

http://www.subwoofertools.com/forum/ported-box.asp?Ew=34&Eh=15&Dia=9&Xmax=22&Vd=.18&NumW=1&Vb=4&Fb=32&Qts=&Vas=&Fs=&CE=0

the pink side to the black side, that width is about an inch smaller than the green to teal sides.

profundus-sanus
05-18-2007, 06:41 PM
you definitely want to maintain a constant port area.

You would have to calculate the tuning of the smaller area part then just guess hwo much lower it might be tuned.

Since its just a step, the tuning is really calculatable, with common knowledge i'm aware of anyway. It may act somewhat like a horn tho. Just having two tuned frequency instead of a tuned range that a horn has.

If it was a linear and constant change or exponential change in area then it would be a horn, but just stepping up the size from what i can conjur up would just make it a useless waveguide, that would only possibly help phasing.

Simple answer, don't do it.

NoPh33rRaCiNg
05-19-2007, 12:37 AM
**** alright i kinda ****ed up on the cut. ill short the first port wall. its my first box build