ok if you yell loud or the dog barks it makes a funny sound like hmmmmm hmmmhmmm.. ok? lol when u hear it you stop talking and look around and say what is that noise!! the dog basically does the same thing and it forgets that it was barking and its looking around for the funny noise! so my chi used to bark a lot then it tried to find this deal.. i put it diffrent parts of the living room/ front door area so it is looking for it. Forgets about barking all the time! then it just didn't bark as often.. now not a barker! boom! great invention! free arizona desert dust on it as well!