analogRead and pulseIn


I'm trying to use analogRead to input some sound, and I want to use pulseIn to measure the duration of a certain threshold; but I'm having trouble once I put the pulseIn function into the code, it freezes up the seria.println for some reason. I've tried to search and seems like pulseIn can only be used for digitalInPuts, is that correct?

Any insights would be much appreciated. Thanks