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bcarpenterfhl
12-11-2004, 05:43 PM
I tried to do it myself, and got a different figure than Bassbox Pro. I just wanted double check it before i make all my cuts.

Box Volume: 3.648 ft.^3
Slot Width: 2.5 in.
Slot Height: 14.5 in.
Slot Length: 21.125 in.

Damaso87
12-11-2004, 06:22 PM
http://www.caraudio.com/vb/showthread.php?t=68635 <- Start pluggin numbers in

bcarpenterfhl
12-11-2004, 06:35 PM
i'm getting all different answers for the audiobahn.com calculator, the12volt.com, and bass box pro. can someone whos good with this stuff figure out the frequency with from the information previously given. im trying to achieve a frequency of 33.7 Hz. and the only dimension that can change is the port length.

g30ffr3y
12-11-2004, 06:55 PM
with a slot that wide your going to need a hell of a lot longer port... me thinks...

bcarpenterfhl
12-11-2004, 07:25 PM
ok change of plans. i want to widen the vent to 2.75 inches. so my new vent dimensions are:

w: 2.75 in.
h: 14.5 in.

bassbox pro says i need a port length of 24.68 inches to achieve a frequency of 33.7 Hz. (fyi this decreases my Vb to 3.483 in.) but audiobahn.com says i need it to be 19.35 inches. i just thought of something. Bassbox Pro takes into account port displacement, perhaps adiobahns calculator doesnt?

bcarpenterfhl
12-11-2004, 07:28 PM
can someone please verify my Bassbox Pro calculations?

DBfan187
12-11-2004, 07:32 PM
ok change of plans. i want to widen the vent to 2.75 inches. so my new vent dimensions are:

w: 2.75 in.
h: 14.5 in.

bassbox pro says i need a port length of 24.68 inches to achieve a frequency of 33.7 Hz. (fyi this decreases my Vb to 3.483 in.) but audiobahn.com says i need it to be 19.35 inches. i just thought of something. Bassbox Pro takes into account port displacement, perhaps adiobahns calculator doesnt?
BB6P takes the subs displacement into account. That's why it's longer. The online calcs don't.

bcarpenterfhl
12-11-2004, 07:52 PM
oh ok thanks a lot.

bcarpenterfhl
12-11-2004, 08:49 PM
why not?

bcarpenterfhl
12-11-2004, 08:59 PM
f**k! this is becoming so complicated. then whats the poinit of their slot feature?

bcarpenterfhl
12-11-2004, 09:01 PM
can anyone tell me how to calculate a slotted port displacement?

bcarpenterfhl
12-11-2004, 09:03 PM
oh ok thanks, so that means it probably wont even calculate my frequency right cause it cant get an accurate displacement of the port, huh?

bcarpenterfhl
12-11-2004, 09:56 PM
ok. i get Cs in math. can someone please help me out. The slot height needs to be 14.5 in., the width 2.75 in. The total box internal volume w/ driver displacement is 4.255 ft.^3. all i need to do is figure out the port length the achieve a tuning of 33.7 Hz. I've tried m best on this, and havent been able to figure it out. can someone please help me out?

bcarpenterfhl
12-11-2004, 10:06 PM
i know, i did that, but then my frequency changed. i dont know how to get my frequency with the port length b/c everytime i put in the port displacement, the volume changes, thus changing the frequency. im just having so much trouble figuring out something that should be so simple.

DBfan187
12-11-2004, 10:33 PM
Design the box first.(Before entering in the subs specs)

bcarpenterfhl
12-11-2004, 10:43 PM
yea, but then that wouldn't take into account driver displacement, so after i'd enter the driver displacement in, the Vb would change and so would the frequency.

DBfan187
12-11-2004, 11:08 PM
yea, but then that wouldn't take into account driver displacement, so after i'd enter the driver displacement in, the Vb would change and so would the frequency.
After the design is done, you then enter the subs specs. BB6P does the rest.

bcarpenterfhl
12-11-2004, 11:30 PM
so i dont need to worry about port displacement now?

DBfan187
12-11-2004, 11:33 PM
yes

bcarpenterfhl
12-11-2004, 11:36 PM
so does this make sense now calculation wise:

http://img31.exs.cx/img31/6215/box3sc.jpg

bcarpenterfhl
12-11-2004, 11:37 PM
sorry the port width is supposed to be 2.75 my bad.

DBfan187
12-11-2004, 11:43 PM
OK, this thread got me allllll confizzled!

bcarpenterfhl
12-12-2004, 12:14 AM
does the above look right Jmac? i did what DBfan suggested and got different results.

bcarpenterfhl
12-12-2004, 12:20 AM
i added 3/4 of an inch. whatever couple Hz off wont mean anything right?

DBfan187
12-12-2004, 12:31 AM
Well I'll be damned! What threw me off was that somehow I had a shitload of pollyfill clicked.