Producing sustained, amplified, high-frequency (17-19khz) sounds

[thrownawayxx]

Hello,

With generating a given high-frequency tone is the easy part, how can I build / where can I find a speaker capable of actually playing the amped-up tone for sustained periods (<30 minutes) without breaking or quickly degrading?

Most commercial components and products I've found don't seem to be rated for frequencies above 17khz. Any suggestions?

 

[FvM]

Compression tweeters as used in PA systems should be suitable, e.g.:

 

[DXNewcastle]

Additional factors which you might want to include are the coil's cooling mechanism of the compression drivers. Large magnets and large coils will provide the power you require, but in an air gap, the failure rate may be unnaceptable. HF drivers operating at high power often include a 'Ferro-fluid' in their gap which transfers heat from the coil to the magnet much more efficiently than air. I wish you'd tell us what power level or what dB level you require. I might be able to recommend something more specific - but it unlikely to be cheap! For example, a B&C 'DE75' high frequency driver with 3 inch voice coil costs over £200 UKP. They'll provide 103dB per Watt at 1 meter. When you burn that out, the replacement diaphragm will cost you just over £100 UKP.
Hope that helps.

 

[FvM]

A horn driver like DE75 has a nominal frequency range up to 18 kHz, but actually a considerably drop of sensitivity above 8 or 10 kHz. That's why horns are usually supplemented by ring radiators for high frequencies.

http://www.prosoundservice.com/uploaded/files/de75ptn.pdf

The said CP22 (or the original JBL ring tweeter which it's copied from) have a lower power rating, but a higher effective sound pressure above 10 kHz. It has a 25 W AES rating, which is referring to pink noise rms continuous load.

By this measurement method, it can't be excluded, that the driver has resonances which may cause a mechanical overload when stimulated at full power. I guess, that the original poster was referring to this kind of problems with the term "breaking". Although the CP22 frequency characteristic looks almost flat, this can't be strictly excluded. The risk also depends on the intended output level, of course.

As effectively resonance-free speakers, but with lower sound pressure, ribbon tweeters, electrostatic types or plasma speakers should be considered.