We have that same problem here. I apparently hear like a bat, and the DH hears low tones, and misses a lot of the higher pitched stuff. My hearing though isn't terribly good with direction, so when we're trying to figure out where a noise is coming from (like in the car, for instance), it can get pretty comical.
You can probably "see" the noise we're talking about. The needle bottoms out, then does a tiny little bounce. This bounce causes a little "thump", then when the shuttle begins its drive forward, it grabs the thread, and you see the shuttle pitch to the left a little as the thread goes between the first "claw" of the holder and its shuttle. It "clicks" and the shuttle rocks back to the right, sometimes there's a slight noise here, another click. The thread travels further, then goes under the second claw, click click.
They're not bad noises, but I sort of think that the motor seems to amplify it a little, and I sew "faster" with a motor than when I treadle, so there's more noise due to the higher rpm. Enough so that I would use another machine if the DH was sleeping across the hall. During the day though, any machine is fair game.
as far as tension is concerned (might as well keep it somewhat on topic, eh RBS?) I wonder if the shuttles can use the same "rule" for setting their tension.
I posted a thread a while back about setting the bobbin case tension for a 99 / 66. It said that an ounce of weight should have the thread -almost- coming off of the bobbin. If I can come up with a way to verify that this is the same for the shuttles, I will definitely post about it. I want to know too, since I have 4 of the things here that should probably be set correctly. That may help you lead your dance. If it's set rationally at the bobbin side, the top tension should be easier to reign in.