Head unit ticks with transducer

Anyone ever put an ear on the head unit. My HDS unit clicks right along with its transducer.
My Garmin doesn't so I'm wondering if this indicates the Garmin has a problem.

My Garmin does it and my old Onix did too. My HDS Gen3 doesn't. Just depends on the unit I guess.

so, i'm learning ticking or not ticking is not an indicator of proper working order.

thanks,