PDA

View Full Version : Finding port wall lengths



Thuracine187
11-30-2004, 10:45 PM
Having a little trouble with this.

Ok i know my physical pL is 20in and my depth is 18.5(internal)

First wall = Depth - port width 18.5 - 2 = 16.5 in

Second Wall = Physical pL - (internal depth + 1.5) 20-(18.5+1.5) = 0

thats the part where i get confused

does that mean i dont have to make a second wall or what cause im not sure

*edit* i change the physical pL to 20 b/c that would be closer to the 33hz i want

Fb = 0.159*Sqrt[35*1.84*10^8/(5989.375(20+0.823*Sqrt(35)))]
Fb = 33.06136067

Thuracine187
12-01-2004, 12:16 AM
*Bump* for the edit

LBX2G
12-01-2004, 12:29 AM
one answer i can give u is that. yeah u will have 2 walls:

one that runs parrelle to the side wall
and
one that runs parrell to the back wall

if u need pics i can post them.


(sorry about the spelling)

Thuracine187
12-01-2004, 12:38 AM
So if my first wall is 16.5 in but in reality it would be 18in in pL

16.5 + .75 + .75 = 18

so i would need a second wall of 2in to get my 20in pyhsical pL

could some1 tell me if that is correct

LBX2G
12-01-2004, 12:45 AM
see that part i do not kno but i can point u in the right direction

http://www.caraudio.com/vb/showthread.php?t=75259

Thuracine187
12-01-2004, 01:04 AM
so if i measure down the middle

16.5+.75+.75+1 = 19

so 19 would be the Pl with the first wall in

making the second wall 1in would give me the 20 pL

now that i think i have its time to draw out a diagram of the box

LBX2G
12-01-2004, 01:08 AM
Like i said before i do not kno but here is one that will help

http--www.audiobahninc.com-tech-Calculators-PortLengthCalc.htm. (file:///C:/Documents%20and%20Settings/Hagan/Favorites/http--www.audiobahninc.com-tech-Calculators-PortLengthCalc.htm.url)

Thuracine187
12-01-2004, 01:33 AM
been messing around with autocad 2005 and with the first wall 16.5in that should give me my 20in physical pL

16.5(port wall) + 1 + 1 +1.5(mdf)

LBX2G
12-01-2004, 02:31 AM
http://www.audiobahninc.com/frame2004.html

^^^^^^^^ check that out........