Even pumps marketed as whisper quiet typically have >30db noise. I don't know what pressure/flow rate the ET arm requires, but but if you are getting by with a low pressure pump, there is no reason to add the complexity, condensation issues, and expense of compressors. You might try the pump in an insulated & vented wood box. I cut noise of my 30db Rena 400 air pump in half by encasing the pump in a carapace of soft modeling clay, and placing pump and flow tank inside a plywood box insulated with several layers of cut-up acoustic ceiling tiles.
