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nismboy6986
03-21-2005, 12:52 PM
say i was making a enclosure that would be 3.5 cubes after displacements tuned at 30hz. the port would be 3"by 15" and winISD freeware gave me a length of 31.16" but i'll use 31" instead. the port would be a L shaped port exiting through the front baffle utilizing the enclosure walls as one side of the port and 2 pieces of woof creating the other side.
the enclsosure would be internally 15" tall and 20" deep
portwall 1 which would be perpendicular to the front baffle would be 15"x16.25
portwall 2 which would be adjacent to the back wall would be 15"x 11"
portwall 2 would give up .75" of its length to compensate for the added length of the the thickness of the wood at the joint between it and portwall 1.
since my physical length would be 31" i figured out it my effective length would be 29.5" since i would subtract 1.5" (1/2 of port width) for endcorrection
i figure out my wall measurements by running a line that would stay in the middle of the port at all times and basing the length of portwall 2 on it.

would this be the correct way to design a port? if not can you please show me where i went wrong since i need to know this since i want to install as a career.

and can i plug the formula for finding port length into the Windows grahping calculator or do i need a TI graphing calculator or something.

DFW40
03-21-2005, 04:14 PM
Sounds about right to me measure down the middle

hdave
03-21-2005, 06:40 PM
say i have a 20" port, and i break it up into 2 10" parts.

which way do i measure it, the first or the second?

http://www.uoguelph.ca/~hdave/port.JPG

Moe Lester
03-21-2005, 07:05 PM
the 2nd way, with straight lines :p:

hdave
03-21-2005, 07:26 PM
thanks

nismboy6986
03-22-2005, 10:49 AM
so moe would i be right on how i think i should do it??

Moe Lester
03-22-2005, 10:57 AM
i believe youve got it right.

nismboy6986
03-22-2005, 11:09 AM
thanks for your help about time i finally get this port design right. i think my current enclosure is actually tuned in the 20's since i added length to the port instead of subtracting but oh well ID's large box recommendation it 2.7@28hz anyway.