I heard what’s often referred to as piping from the bottom of Hive #1 yesterday. (Read more about piping at Honey Bee Suite.)
Piping sounds usually come from newly emerged queen bees. We requeened this hive back on July 11th. I’m not sure what to think. Perhaps it’s not piping at all. At any rate, I got it on tape:
You might need to crank up your speakers.