atomic apx 18"

[uhoh45 10+ year member]

im lookn to build a box for an atomic apx 18 heres roughly the the dimentions in this photo i just dont know how big to make the port tryin have it tuned to 32-40 hz

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[mikey060 10+ year member]

are you wanting to know how much port area you should have, or how long the port should be, or all of the above

 

[uhoh45 10+ year member]

both

 

[rpfuror 10+ year member]

This would be highly dependant on how you want the box layed out and what type of port do you want to use.

To give you an example, based on the outside values you gave. If you want a slot ported box with the port on the same face as the sub, you would have the following:

Net Volume: 7.60 cu/ft

Tuning Freq: 40.00 Hz

Slot Vent Width: 3.00 inches

Slot Vent Lenght: 11.00 inches

Port Volume: 85.50 sq/in

or

Net Volume: 6.70 cu/ft

Tuning Freq: 32.00 Hz

Slot Vent Width: 3.00 inches

Slot Vent Lenght: 26.00 inches

Port Volume: 85.50 sq/in

Now this will be completely different if you want the port on the 15" panel or with round ports.

 

[AudioXtremes 10+ year member]

With that sub your gonna want close to if not more that 100sq" of port.

 

[rpfuror 10+ year member]

I usually base the port area on the net volume of the box, to give people an idea of what they are looking at.

JFYI, if you wnat more port area you will drastically effect the amount of net volume your driver see.

 

[uhoh45 10+ year member]

http://www.stevemeadedesigns.com/forums/index.php?topic=143.0

well i was looking to build the box like this but for one single 18" sub

 

[rpfuror 10+ year member]

looks just like one I designed for 2 12s

and another for 12 15s

 

[mikey060 10+ year member]

port is 6"x19"=114^2" of port area. and it is 20" long tuning it to 35 hz

. after port displacement, it is 7 cubes

exterior dimensions are 36x36x14.75..im not sure that you would need a double baffle or not, probably better going with one though