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View Full Version : what frequency this box is tuned to? or how to calculate?



04murdalanche
05-16-2012, 03:05 PM
http://www.ddaudio.com/media/54638/12_full_size.pdf

can someone please tell me what frequency this box is tuned to? or how to calculate the port in relation to the box?

thanks in advance,
Jeff

Fi_
05-16-2012, 03:11 PM
If I had to take a shot in the dark between 33-35hz.

04murdalanche
05-16-2012, 03:14 PM
If I had to take a shot in the dark between 33-35hz.

okay thanks

im looking to do a center console.. 2.5 cu feet tuned to about 33-35 hz, so this was perfect

and i was on DD's website, ran across this and figured id ask.

Fi_
05-16-2012, 03:16 PM
okay thanks

im looking to do a center console.. 2.5 cu feet tuned to about 33-35 hz, so this was perfect

and i was on DD's website, ran across this and figured id ask.

If I knew the height of the box I could probably get a way more accurate guess but based on boxes I've built and how that port looks it seems around mid 30's.

04murdalanche
05-16-2012, 03:19 PM
If I knew the height of the box I could probably get a way more accurate guess but based on boxes I've built and how that port looks it seems around mid 30's.

it says
24x15.25x14.50

pro-rabbit
05-16-2012, 03:20 PM
If I knew the height of the box I could probably get a way more accurate guess but based on boxes I've built and how that port looks it seems around mid 30's.

OD
H-14.5
W-24
D-20

ID
H-13
W-22.5
D-18.5

Port
3 x 13
20.25(ish) long

Fi_
05-16-2012, 03:21 PM
Ok it's tuned roughly around 39hz so I lied :D didnt see the other pictures just the top one haha ya that box is a bit on the high side of 30hz.

If you want to tune it slightly lower do a 2.75" wide port and make it a couple inches longer like like 4-5" and make it have an L bend and use 45's to reduce port noise/loading and to take up some extra space.

pro-rabbit
05-16-2012, 03:23 PM
Ok it's tuned roughly around 39hz so I lied :D didnt see the other pictures just the top one haha ya that box is a bit on the high side of 30hz.

yea, it is around 2.56ft3 and 40ish(before sub displacement)

May work decent, depends on the application and desired response.

04murdalanche
05-16-2012, 03:24 PM
Ok it's tuned roughly around 39hz so I lied :D didnt see the other pictures just the top one haha ya that box is a bit on the high side of 30hz.

yikes, too high.. what would need to be changed to get it down to about 34?

sub is a HDC3 12" on a AQ 1200 btw

Fi_
05-16-2012, 03:31 PM
Decrease port width to 2.75" and make the port length about 6-7" longer with an L shape bend. I would consider a double baffle which would decrease inside volume and allow a few 45's to help take up space and increase air flow. Also with that type of power/sub I would double baffle for the lows.

Theres many ways to go about it but yeah that's my suggestion Pro-Rabbit could probably provide better advice.

Fi_
05-16-2012, 03:34 PM
Ok do this:

L-SLOT Enclosure.
2.5" Wide Port
28 Length
Double Baffle
45's in EACH CORNER

I included that with bracing and it came to 2.23ft^3 34hz 15 inches of port
box is slightly on the smaller side but should work fine.

04murdalanche
05-18-2012, 01:04 AM
Ok do this:

L-SLOT Enclosure.
2.5" Wide Port
28 Length
Double Baffle
45's in EACH CORNER

I included that with bracing and it came to 2.23ft^3 34hz 15 inches of port
box is slightly on the smaller side but should work fine.

thanks man, im gonna draw it all up and PM you to check everything but i think ill be able to do this all on my own, i appreciate the help..