"Len Moskowitz" wrote in message

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?

Vifa has one that goes that high.

http://www.d-s-t.com/vifa/data/xt25tg30-04a.htm
http://www.d-s-t.com/vifa/data/xt25tg30-04c.htm

Not frightfully expensive:
http://www.partsexpress.com/pe/pshow...64-555&ctab=14

Similar, higher priced, same factory - the Scan Speak R2904/700000

http://www.d-s-t.com/scs/index.htm