Chassis volume measurement

Hi People,
I am kind of wondering about how to best construct a loudspeaker.
Now given that in the end I get some volume for the Box that I need to build. but the problem is, that when I build in the Chassis I loose some volume (Chassis cone and magnet at the minimum)
Is there any tested technique how to best calculate or measure this volume?

kind regards
huegene
 
> any tested technique how to best calculate or measure this volume?

Geometry?

Computing the volume of a cylinder or cone is fairly easy. And in most cases, make nearly no difference to the result. A so-called 10-inch cone might use a 1700 cubic inch box, the cone is about 11 cu.in., the magnet maybe 30 cu.in. 1700 or 1659 is only 1.3% difference in resonant frequency, and ALL loudspeaker parameters vary more than that.