Len Moskowitz wrote:
We're working on an interesting application that needs a super tweeter
that can operate at 40 KHz. Anyone have a favorite driver that they'd
like to recommend?

I can't recommend any.
But I know that Pioneer/TAD makes one which is very well respected.

And I know that, if you can live with some spikiness, the Motorola
piezo tweeter is available in a model for super-20KC use that is dirt cheap.

I think some of the smaller ribbon drivers will do ultrasonics, but
they won't go all the way up to 40 KC.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."