The camera may be amplifying the sound. I know that mine does.
I just came back from testing the sound level

My Compak K10 measures 65dB at 1.5 feet distance and no beans. At 2.5 ft is only 62dB. The distance to the mike really affects the sound level.
My BrewtusIII measures 62 dB with pump on at hand distance (~2.5 ft)
PS: The lowest scale of my meter is 60dB. So it may be even lower than measured.