Quote Originally Posted by aditya View Post
Put the piston dia at 12.58 inch. And repeat the Vas measurements with different weights, and note the results. Choose weights to shift Fs between 15% to 40%, and note the changes in the readings. It takes some effort to get the correct data for Vas.

Also take a 'in-box' impedance reading. This will help.
Yeah when measuring the VAS piston area (cone/dust cap) will always be in cubic inches.So when trying to figure the correct data to enter you are essentially trying to figure the total piston area in cubic inches.. And adding the correct weight does take some effort..

VAS methods

1. Added Mass
2.Known Box

Measuring Loudspeaker Driver Parameters