Tweeter parameters, Dome

[urbs]

Hello
First time poster here. Thanks for all the good work done at DIYAudio.
I am having a bit of trouble understanding tweeter specifications.
I would like to know ....
1. How is "effective piston area" calculated for a dome tweeter.
2. Are most dome tweeter domes hemispheres ?
3. Some seem to be radially smaller sections of spheres. But I can't really tell from
pictures Is there any way to infer the radius of the dome from a manufacturers spec sheet ?
4. Perhaps these dome radii are peculiar to a manufacturer ?

Sorry if this is basic stuff. I couldn't seem to formulate a "search" that would tell
me much about this. Any pointers to this would be appreciated.

Al

[speaker dave]

Effective area is just the circular area as viewed from above. The depth of the dome (height across the middle) doesn't matter. Usually the inner portion alone is calculated (inside the half roll of suspension).

Few domes are total hemispheres. For one thing that is a hard shape to form as the starting angle at the edges would be quite steep and the depth would be half the diameter. Most domes are a sector of a sphere with a starting angle of about 30 degrees off the surface . This is concave enough to give good strength.

The actual dome shape is usually empirically derived. Most manufacturers don't explicitly define them but you might be able to estimate them from photographs.

David S.

[urbs]

Hello Speaker Dave
Thanks for the reply !