Which types of motor are the most quiet from a mechanical and electrical point of view? To avoid quiet, but weak, suggestions, the motor needs to be capable of about 70 Nm of torque and speed range from 600 to 2400 rpm.
Have you considered a hydraulic motor?
Have the pump power unit remote in another room for example, which keeps that vibration separate.
The speed is achievable and can be finely controlled.
There won't be any electromagnetic interference produced which seems to be one of your important parameters (electrical noise).
You can either use asynchronous motor or synchronous motor Asynchronous motors is quiet compared to synchronous but their speed highly depends on load and frequency . Synchronous make little bit more noise because it has brushes to make magnetic poles but you can adjust the speed by lowering the DC current in magnetic poles