And when they can't hear its even better. Last Friday- Me: " Holds on 71 coach"
Coach: "61 ain't even in the game, how can you have a hold, blah blah blah?!"
Me: "I said 71 and he's standing right there", as I point towards my hashmarks.
Coach: Hangs head and turns away.
I had a similar exchange recently...
Me: The hold was on 66 (who I happened to be standing next to).
Coach: COME ON, MAN... WE DON'T EVEN HAVE A 66. THAT'S TERRIBLE!
Me (turning 66 towards his coach so the coach could see the front of his jersey): Coach, let me introduce you to 66.
Coach:

Not another word from him all day.
Back to the OP, I try not to "over communicate". The coach has a job to do and I don't want to distract him from his job any more than I want him distracting me from mine. If the clock status is important information for him to have (end of a half, end of a quarter if significant weather exists, etc.), then I'll give it to him. If he asks, I'll give it to him. I'm not going to offer it all the time for no specific reason.