input on quitting my wet/dry system

Not enough info.

What type of overflow? Internal, HOB?

And where is the noise, overflow or splash in the sump?

splash into to the glass media.

Does it have a drip plate or is it dumping straight in?

You could fill the area where the water is dripping with pot scrubbers or filter fiber.

if you could lower your plate that allows the trickle down to as close to the water as possible that would be your best bet... are you injecting co2 by chance?

there is a reason its called a wet/dry, for your biomedia to work best the ceramics are supposed to be above the waterlevel, not submerged, so the drip runs over them and they are exposed to air, this allows maximum aerobic filtration, this will also help it run quieter. if it were I, I would add more biomedia to bring it up within an inch of the drip plate, this will do a few things, reduce the distance the water is falling reducing impact noise, as well as increaseing the biologic capacity potential.