Try this site
http://onlinetonegenerator.com/

Some things to consider:
 
http://pets.thenest.com/there-highpitched-whistle-make-dogs-stop-barking-constantly-11318.html
 
http : // pets thenest com / there-highpitched-whistle-make-dogs-stop-barking-constantly-11318
 

TheMaartian
Some things to consider:
http://pets.thenest.com/there-highpitched-whistle-make-dogs-stop-barking-constantly-11318.html

Indeed, sometimes these dog whistles "work" but if they end up causing these junkyard dogs to bark more, at least I can induce them to bark at times less convenient for their rude owners, and perhaps they'll choose to do something about it. A bit (more) off topic, but I'm amazed at how chronic "security" dog barking is not considered rude by many, but if someone's car or house alarm wailed every time someone or some animal passed within view, then that would be considered a nuisance.
 
... I forgot to mention that my first hope is that the dogs will become desensitized to stimulants such as these noises, and start ignoring more triggers. If not, then at least the owners might suffer as much as the rest of us.

I'm now at the stage of having the 16--20KHz tones but after exporting them to .wav files and playing them on anything but my Focusrite Scarlett (e.g., playing them on my SoundBlaster or iPod), there are a lot of audio artifacts lower frequencies (buzzing, etc.). Yet, on the Scarlett, the master sounds fine, and if I import the exported .wav back in to Sonar and play it over the Scarlett, it looks (spectrum) and sounds fine too... so the problem isn't with the .wav exporting, but with the playback devices?
 
I'm wanting to load this .wav on an iPod 2, but that too exhibits the problem artifacts.
 
Does anyone have any work-arounds to possibly consumer hardware not being able to output high-frequency sine wave .wav files clearly? Perhaps I'm missing something?
 
Thanks!

It's probably hardware dependant.  A lot of consumer grade stuff wont give you 20 - 20 like a high quality audio receiver.