PDA

View Full Version : When doing an L-port, how do i measure the port?



I Like Waffle
05-22-2009, 04:32 PM
Just as the title says, im wondering how i measure the port out to do an L port in a box im gonna build. Im familiar with doing sealed and aero boxes but never a slot port. Do i measure the outside of the box wall for port length? Or do i measure the straight part, then measure the other end of the L add and those together to create the length?


Box in question is a 3.6 cube box tuned to 35 hz, port length is around 20 inches. 4"x11" port. Other reccomendations are welcome as well.

mlstrass
05-22-2009, 04:35 PM
measure down the middle of the port...might also want to do a search on "end correction"

rollerdj
05-22-2009, 04:36 PM
When I build any slot ported boxes, I allways draw them out full size on something. I draw a line going down the center of the port the whole length and measure that. Seems to work for me.

DonH
05-22-2009, 04:38 PM
measure down the middle of the port...might also want to do a search on "end correction"

this....


also an angled piece should be placed in the corner

I Like Waffle
05-22-2009, 04:55 PM
measure down the middle of the port...might also want to do a search on "end correction"

I found a few topics on end correction, but nothing that i could understand real well. But heres what i got from it, end correction is something needed when one of the box walls also serves as a port wall, and when that happens half of the port width needs to come off the end of the port? So i would measure down the middle of my port, then instead of making it 20" i would make it 18? :confused:

mlstrass
05-22-2009, 07:38 PM
If the port is 4" wide then you would take 2" off the over-all length otherwise you'd be tuned a little lower then planned. Honestly I don't even do it anymore as it never seems to make much of a diff for daily boxes and most guys like to play the low stuff anyway...