What is the formula for finding Cubic ft for a speaker box?

Discussion in 'Archived Threads 2001-2004' started by Sebastian, May 5, 2002.

1. Sebastian Second Unit

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Is it HxWxD? or is that surface area?

2. eric nyhof Stunt Coordinator

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it is HxWxD, which would be in feet cubed.

Surface area is feet squared and is only the are of a side

3. Dustin B Producer

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Don't forget to account for the thickness of the walls, any bracing and any volume displaced by the driver and port if present.

4. Wayne A. Pflughaupt Producer

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Of course, you have to use the interior H x W x D dimensions, or else subtract the wall thickness from the exterior measurement.

If you are measuring in inches, divide the total cubic inches by 1728 to get the number in cubic ft.:

E.g.:

22” x 18” x 16” = 6336 cu. in.

6336 ÷ 1728 = 3.6 cu. ft.

As Dustin mentioned, you have to subtract the displacement of any braces from that figure (using the same method). Not sure how to figure the displacement of the driver – perhaps the manufacturer could tell you that.

Regards,

Wayne A. Pflughaupt

5. Dustin B Producer

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You don't have to be that precise with the driver if you are reasonably precise with the rest. Use 5L for a 15" driver and 3L for a 12" driver. Should be close enough.

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