I can't comment on this directly and my dad served in the
USAAF flying B-17's out of Italy. And most of my other relatives who served have since passed. But my father did say that he asked a few ground-pounders in Italy about it when they had come off the line to the rear. Universally, their response is "Nah, the [Germans] can't hear it over the constant firing. In fact, sometimes it's easier to hear the *ping* from the guy next to you than your own."
If anyone wants to see how fast a Garand can be fired and reloaded, rent a few episodes of the old
Combat TV show and watch Pierre Jalbert ("Caje"). While these were modified blank-firing Garands, he can reload in about 1~1.3 seconds. I caught him talking about the show on a late channel one night. He actually bought his own M1 and practiced with it until he could empty 8 rounds in 5 seconds an reload in under 2 seconds. (yes, he said he had a callous on his shoulder from all the practice too!
)