an acoustic transducer is disclosed including : a fixed perforated member ; a freely movable diaphragm spaced from the perforated member ; a support ring in the perforated member maintaining the proper spacing between the diaphragm and the perforated member near the perimeter ; means of suspension allowing the diaphragm to rest freely on the support ring and yet mechanically decouples the diaphragm from the perforated member ; means of applying an electrical field in the space between the perforated member and the diaphragm ; means of detecting the change of electrical capacitance between the perforated member and the diaphragm when the diaphragm moves in response to an incident acoustic sound pressure wave .