Calculate box air volume.

[Too Tall]

Hi,
When I figure the air volume of a box I need to subtract things such as port volume, bracing and the room the driver takes up. Mostly cone drivers.
I had this information for 5", 8", 10", 12", 15" and 18".
I believe I got this from one of the driver manufacturers (Eminence?), but I can not find it.
If anyone has these figures let me know.

NOTE: I understand these figures are not accurate , but they work well enough in practice.
Looking at the back of the driver and adding Kentucky Windage helps.

Thanks.

[Ron E]

Curt?
One way to estimate is use the volume of a cone the diameter of the driver piston and the depth/height of the magnet. V = pi*rb^2*h/3 so if you have a 12" driver with a 6" magnet height the area of a cone ~10" in diameter (5" radius) and 6" tall is 5^2*6*pi/3 or 157 in^3 or 0.09 cubic feet or about 2.6 liters (a liter is 61 cubic inches more or less)

Another thing I have read in the literature is somewhere between 0.4 and 1.0 times the advertised radius cubed, which would be 86 to 216 cubic inches in the example above.

For the most part this is insignificant, but it can add up.

[Neil Davis]

Originally Posted by Too Tall

Hi,
When I figure the air volume of a box I need to subtract things such as port volume, bracing and the room the driver takes up. Mostly cone drivers.
I had this information for 5", 8", 10", 12", 15" and 18".
I believe I got this from one of the driver manufacturers (Eminence?), but I can not find it.
If anyone has these figures let me know.

NOTE: I understand these figures are not accurate , but they work well enough in practice.
Looking at the back of the driver and adding Kentucky Windage helps.

Thanks.

This calculator will get you closer:

Speaker Driver Displacement Calculator Help

[Too Tall]

Originally Posted by Neil Davis

This calculator will get you closer:

Speaker Driver Displacement Calculator Help

That is quite a piece of work.
I wish I could download the ap so I know I have it for the future.
Thanks

[Too Tall]

Thanks Ron

[tassie tiger]

Hi there Too Tall.

Also, don't forget that damping/stuffing materials will actually increase the apparent (calculated) volume of the enclosure. Refer to the bottom of Troels Gravesen's web-page about this:- http://www.troelsgravesen.dk/ports.htm

Cheers,
J

[Ron E]

Originally Posted by Too Tall

Thanks Ron

For giggles, I looked up the old Adire Shiva 12" driver and the specs say 3 liters or 183 in^3. So my method at 2.6 liters is fairly close. I put in shiva dimensions and got ~1.85 liters in the calculator page....