Does Vas tell of compliance?

[Tom Loizeaux]

If I want to judge the compliance, or softness of a speaker's surround, does a low Vas figure tell me it's softer? Doesn't a softer compliance indicate it's ability to work in a smaller, or sealed enclosure, as compared to a higher number Vas rating?
Can someone shed a little light on this?

Thanks,

Tom

[Earl K]

Hi Tom

It would be much better if Giskard explained the relationship between
"Compliance" and the "TS" parameter Qms.

Qms is a unit of measurement that will also describe " Compliance" because its' a measurement of the mechanical resistance .

Vas is a more complex measurement that also involves the weight of the cone
( and air-mass being "pushed" by the cone; Mms ) among other parameters .

I think you've stated your "premise/argument" incorrectly .
A "large" value Vas will just about always indicate a high compliance .

<. Earl K

[Tom Loizeaux]

Earl,
This is already helping!
Thanks,

Tom

[speakerdave]

From the Parts Express Tech Talk Page:

"Vas (volume of air having the same compliance as the driver suspension)"

Larger volumes of air would be more compliant.

David

[John Sheerin]

Vas=p0*c^2*Sd^2*Cms

p0 = density of air, c = speed of sound, Sd is cone area

So a higher Cms gives a higher Vas, ie, a softer suspension gives a higher Vas.

John