# Estimating basket volume

#### Studley

I plan on making a couple of sealed subs using a pair of the legendary Aurasound NS15 woofers. I’m decidling on the box volume but I need to make an allowance for the huge magnets and frames of these woofers. Is there an approved method for estimating the volume displacement within the box?

#### Galu

I don't think you would be too far out if you simply imagine the woofer as a solid cone as far as its volume displacement is concerned.

The volume occupied by the woofer can then be calculated from the equation for the volume of a cone:

Woofer Volume = (1/3) * 3.14 * (Woofer Radius)^2 * (Woofer Height)

This calculator also allows you to treat the woofer as a truncated cone: https://www.omnicalculator.com/math/cone-volume

I've started the ball rolling at least.

#### stv

Paid Member
Also consider the "added" volume of woofer cutout. Depending on the baffle thickness this can be quite big.

Thanks guys

#### rabbitz

I find it easy just to calculate the volume as a cylinder using the magnet diameter x the full height to the face plate. Gives a volume thats close enough.