PDA

View Full Version : quick question about port length



T3mpest
05-28-2009, 05:18 AM
I'm trying to build a box and effective port length on slot ports has me a bit confused. I **** at drawing so I'll explain the best I can. The port is two inches wide. It runs 10inches back into the box and then uses the back wall to run to the right. Two inches over from the edge of the backside of the wall I'd run another ten down. Then repeated one more time back up for a third bend. So three runs of ten spaced 2 inches apart both left and right right bends also being two inches off the front face. What does that make my effective port length. I know it's over 30 but by how much?

MisterGrubbs
05-28-2009, 05:49 AM
Sorry it took so long, drew out an explanation, if it's what you're asking.

http://i13.photobucket.com/albums/a263/MisterGrubbs/PortWallLengthExplanation.jpg

You start at Measurement 1, measure from the front of the port opening to the first dot(which is the middle point). Measurement two is from that first dot to the second dot which is in the next bend. The third and final measurement is from the second dot to the end of the port.

That should give you the total port length.

Edit - - - At least is the way I've always done it and been told to do it.

T3mpest
05-28-2009, 06:20 AM
Sorry it took so long, drew out an explanation, if it's what you're asking.

http://i13.photobucket.com/albums/a263/MisterGrubbs/PortWallLengthExplanation.jpg

You start at Measurement 1, measure from the front of the port opening to the first dot(which is the middle point). Measurement two is from that first dot to the second dot which is in the next bend. The third and final measurement is from the second dot to the end of the port.

That should give you the total port length.

Edit - - - At least is the way I've always done it and been told to do it.

I think I got it now. Tracing it from the port exit into the box. The first walls effective length in my case is 11. 10 for the wall and half way up a two inch gap is 1. Then to make it to the half way point of the next bend is one inch, since wall to wall was two. Then its exactly a ten drop down to the next midpoint. Then it would go back one more time to the back of the box so that's ten more. Then the exit to the port from the midpoint would be one. So that's 11+1+10+10+1=34? If that's correct then I would just shorten the last wall to eight or so? Is there an issue with the entrance to the port that the sub see's being wider than the rest of it? I tried to make it all square but that's too long in this case. I guess I can adjust the port width if thats wrong.