Does anyone know a program in wich you can simulate a sound source and circuits? I am working with piezoelectric sound sensors so it would be good if I can simulate sound to test the circuit.

 

LTspice allows one to use a .wav file as an input. I've not done this, but I did read the user manual and know it can be done.

 

Is your piezo "sound sensor" used to trigger a recorder?
Is it used as a microphone?
Is it used as a beeper?