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billy18bm
05-16-2007, 11:13 PM
is it true when you use the back of the box to extend your port to your desired length you have to extend an imaginary line (1/2 of the ports width) out like my example below..

also just let me know if this box ends up around 3.10 cuft....@ 36hz....

http://home.comcast.net/~tshot39/illis.jpg
http://home.comcast.net/~tshot39/done.jpg

thanks.

billy18bm
05-17-2007, 09:39 PM
anyone?

04_edge
05-17-2007, 09:42 PM
i dont understand at all.

why would you need to extend an IMAGINARY line?

billy18bm
05-17-2007, 09:50 PM
like when u calculate the box volume and port length.... iamacomputer told me that when you use the back wall of your box you have to subtract half of your ports width?....

Immacomputer
05-17-2007, 09:54 PM
Yes, it is true when part of the port is a wall of the enclosure. Part of the air after the port wall acts as part of the port.

No, I'm not making it up and no, I'm not wrong.

http://mobile.jlaudio.com/support_pages.php?page_id=165

You can see it used there as well if you don't believe me.

billy18bm
05-17-2007, 09:56 PM
lol i didnt say you were wrong i know u know your **** man.. i was just seeing if anyone else knew about this...

Immacomputer
05-17-2007, 09:58 PM
I'm not offended. You would be surprised though... some people refuse to believe that it exists and not many people take account for it -- including Moe's designs.

Trixter
05-18-2007, 02:31 PM
it is true and to accurately tune you need to use it. however, for the most part, if you have a 3" wide port and you add your 1.5", not taking the correction factor into consideration, that 1.5" will make how much difference in tuning....1 maybe 2 hz?? the larger the box and the more port it has, the more critical it becomes.