My puppy has separation anxiety and will start crying and barking when I leave. This has actually cut her barking way back. You can hear that she starts a bark but the sound and vibration deter her (it must be those two at the most because after the second attempt at barking I don’t usually hear her anymore, and the collar is designed to escalate with continued barking from sound deterrent to vibration deterrent to shock deterrent). I don’t think the collar has ever had to shock her. And I’ve never heard her yelp with it either. And I can say I haven’t heard these things because I watch her sometimes from my security camera after I leave to see how she acts.