Air-jet Ultrasonic Noise Source

[Answerman]

"Angelo Campanella" <a.camp...@att.net> wrote in
news:hnpmea$15bv$1...@adenine.netfront.net:

snip.....snip

> To get a braoadband ultrasound source that has both a smooth
> frequecy
> spectrum and a useful intensity, I use an air jet source where the
> sound is emitted in a small region just downstream of a tiny air jet
> running about 1/3 CFM. Millisecond pulsing is pretty much out of the
> question. The sound source needs to be very broad band and reasonably
> intense. Electronic devices are usually not broadband enough, thogh
> the ionophone might do it.

snip....snip

Do you have any measurements of the spectral content of your air-jet source
out to 200kHz. If not, what would you expect theoretically? The upper
frequency limit of my leaf tweeter is 110kHz, afterwhich it rolls off
pretty rapidly. I am looking for an alternative sound source that is
capable of producing a reasonably flat spectrum (eg +/5dB) over the
frequency range from 5kHz to 200kHz. At least temporarily I can live with a
continuous non-pulsed excitation.