I was hoping you would chime in : )
I remembered to see Futtrup
( I think you turned me on to his page years ago)
DPC Manual
Mvac=M(md)
* Mair, Dd
Mair := rho/3*power(Dd,3);
or (when measuring),
Mair := 8/3*rho*power(Sd/PI,1.5);
* Mvac, Mair, Mms
Mvac := Mms - Mair;
Great site! Totally forgotten about it; now if I can just remember which speaker manuf. he work[ed]? for.......
GM
GM