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outspoken
11-19-2008, 09:50 PM
so i know this may get me flamed, but, in an l shaped ported box, longer port = lower tuning, shorter port = higher tuning? i would like to modify my box until i can get a new one built. flame me if you must, i probably deserve it anyway :crap:

P.rick
11-19-2008, 09:51 PM
"longer port = lower tuning, shorter port = higher tuning?"

yes sir

outspoken
11-19-2008, 09:55 PM
o.k., that's what i thought,now how do i figure out how much i need to reduce the port to get it to the freq. i want? it's at 32 now need it to be at more like 38...

simpsonbuck
11-19-2008, 09:57 PM
http://www.bcae1.com/spboxnew2.htm

mlstrass
11-20-2008, 02:17 AM
also realize that changing the port length will change the box volume...

9seconlives
11-20-2008, 03:01 AM
Is it true that every 1/2" in port length (shorter or longer) eitherway is the equivelant to 1hz increments of tuning?

dragnix
11-20-2008, 03:03 AM
Is it true that every 1/2" in port length (shorter or longer) eitherway is the equivelant to 1hz increments of tuning?

never heard of this and i don't think it would be right anyway. Tuning also has to do with box size and port area.

11-20-2008, 03:05 AM
Is it true that every 1/2" in port length (shorter or longer) eitherway is the equivelant to 1hz increments of tuning?

Absolutely not.

9seconlives
11-20-2008, 05:09 AM
never heard of this and i don't think it would be right anyway. Tuning also has to do with box size and port area.

Understood BUT why then by making the port shorter or longer does it change the frequency to which the box is tuned? just curious and not trying to pick a fight with a senior member but it "almost" made sense to me when i heard it the first time. i understand that the size of the box and port are a major factor but i'm use to building by DD's specs most of the time and if i have a 2"-3"x16"port tuned at 40htz then how come if i make it an inch or 2 longer ir will drop it down to like 36 or so? cause you're tuning the box not the sub....maybe it's too late and my meds are kicking my a\$\$ but than you guys for clearing that up for me. :D
here's what i mean though...doesn't matter if you have a 1510 or a 3512 the area of the port is different but the length and tuning frequency is the same..i also understand that thes #'s are not set in stone..
http://www.ddaudio.com/dd/caraudio/enclosureInfo/boxSize_hiEff.asp
SORRY TO JUMP OFF TOPIC!!:crazy:

mcsoul
11-20-2008, 10:30 AM
"longer port = lower tuning, shorter port = higher tuning?"

yes sir

OP, keep in mind the a the depth of the port gets longer for the same tuning when
the port area (port length x width) are increased. The depth needed will also increase for every port when you add additional ports.