No, you won't necessarily know about it.
Firstly, different aircraft behave differently and have different noise characteristics. Secondly, if the gear for some reason is misbehaving, it's at least comforting to know (before you have to ask him politely) that he selected it up, but nothing is moving. In the third place, as I say above, acknowledgement of instructions to provide feedback to the guy with his eyes glued to the instruments is helpful. It's not helpful to insist that the guy has to peer around the flightdeck just to find out if you've followed his request when it takes no trouble at all just to acknowledge him, and to confirm that you're still awake and taking notice. So, in the fourth place you confirm that you are not incapacitated at a rather vital stage of flight. And finally, so you can tell the CVR that it's done and the survivors or the relatives of the victims don't sue you or your widow.
So it's rather more than your dismissive term "mouth music".