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View Full Version : quicky L port questionnn



a_steezy
07-17-2008, 10:57 AM
how important is the bottom of the L, so not the one going straight back, but runs along the back of the box??? i'm building a pretty big box and need the ft^3

if i dont do the bottom of the L i gain +- .5ft^3

but if it's "highly reconmended" then i'm all over it lol

just quicky opions from people that know what's up, thanks guys

squidlover
07-17-2008, 11:04 AM
It's important if you want the box tuned to a certain Hz.
Use this to figure out the port length.

LV= [(1.463 x 10^7 x R^2) / (Fb^2 x Vb)] - 1.463xR

Fb - is the desired tuning frequency of your enclosure in Hertz.
Lv - is the length of your port in inches.
R - is the inside radius of your vent tube.
Vb - is the internal volume of your enclosure in cubic inches. To convert cubic feet to cubic inches, multiply by 1728.

If you want to calculate square vents, the formula below will give you the value of R to use in the formula above.
R=square root of ( A / Pi .

Atleast this is what iv'e been told and what I have used.

a_steezy
07-17-2008, 11:16 AM
ya i know all that, and have the box tuned right, the extra piece only changes by less than 1 hz, and i dont need it that exact, i'm just wondering because people like to play and add stuff to there ports for a cleaner sound, more flush airflow, if the L is nessacary vs. the straight back port

mlstrass
07-17-2008, 12:03 PM
So the "L" part only changes tuning by 1Hz, yet takes up 1/2 a cube? Doesn't sound right to me...

a_steezy
07-17-2008, 04:10 PM
box height is 14" x 6" of the end of the L equals .6?? of a cubic foot, makes perfect sense, but the 1 hz is what it is

box is 36 wide x 14 height x 24 deep

7" port straight back is like 39.8

7" port with 6" L is 38.2, so i guess 1.6 hz. not to much, but i'll probably end up doing that