Re: What is the 'best' method for transporting a sound signal?

Hi Duncan:

I'm going to answer your question in two parts.  

The first part is the 30kHz signal being transported across 'a few hundred 
meters'.  I guess I wouldn't choose to do that.  A better way is to move 
the sound source close to the speakers.  Another solution would be to make 
a couple of really cheap 30kHz sound sources and place them in many places. 
 By making small cheap units, you prevent any costly damages to a good  
sound-system and speakers, and save on energy, and probably have better 
sound coverage in the end. If you have wired electricity available at the 
end of the few hundred meters, then everything should be relatively easy. 

The second is the idea of 30kHz being a pest deterrent. I would feel a lot 
more comfortable if I knew for sure that this will work for the intended 
purpose, before starting on a big project like this.  Perhaps you can 
bounce that question off of a pest control company like Orkin, and see what 
they have to say.

Let me know if you need help with some 30kHz circuit recommendations.

Also, if you are willing to conduct a scientific experiment on that topic, 
let me know.  Maybe we can get one of the biologists and statisticians at MadSci 
to set up the test method with the vermin of your choice, and I'll try to 
provide the 30kHz hardware.  Provided you agree to share the findings with 
MadSci.

Abtin Spantman
SPANTMAN@EXECPC.COM