I too have been assessing providing these creatures with their missing MBAs (moderating barking assholery.)

Here be a device which appears to ramp across various frequencies, some in high biped range (for older dogs) as opposed to the many which are indeed ultrasonic. Though maybe you want it entirely 'silent' so as to mess solely with the reptile brain.

Unclear if schematic/tech data would be forthcoming, though one could ask. Note also the remote; conceivably all you'd have to do is parallel the pushbutton on that -- via whatever electronic *gizmo you want to trigger on, as it is set for barking sounds. This provides your manual control/override at what seems an entirely adequate range.

http://www.ultimateb...ol.com/ds_pro.htm

Am pondering this investment in restoring the lovely silence of these parts pre arrival of:
a Big Pharma sales lackey and their undisciplined yap-dogs + a couple bigger basso profundo robotic-persistent types, (triggered oft by yan neighbor's similarly full-automatic silence assassins.)

Pretty steep $$ so the sucker had better perform as claimed; can't see building a new wheel with transistors and messing about on a breadboard -- if this does what is claimed.

* It may be that all you need is a high-pass filter in microphone amp circuit; I'm presuming that the screams are way ^up^ in the AieeeEEEEE!!! - range, as in Piercing, Man.. Thus the occasional "You broke WHAT ?!" -- ought not to trigger your button-pusher circuit. Could be multiple mics too, of course.

Happy gedanken experiments.