My St Jude's make a dull thump, like a normal heart sound through a stethoscope, except I don't need a stethoscope to hear it. It's not bothersome. Were it a definite click, I might find that irritating. Lord knows why mine's a thumper. I'm rather slight and small and was worried I was going to be annoyed by the mechanical valve clatter, but I find the regular thump is comforting.