A test module for testing microphones comprises an outer chamber being airtight, and a sound chamber comprising an electrical test device for testing the microphones. The sound chamber is located within the outer chamber, and the sound chamber is coupled to the outer chamber with a connection suppressing structure-borne noise between the outer chamber and the sound chamber. A space between the outer chamber and the sound chamber has a gas pressure being lower than an ambient air pressure. A method of testing microphones comprises evacuating the space between the outer chamber and the sound chamber to having a lower gas pressure than an ambient air pressure, and testing the microphone.