Frequency independent directional condenser microphone

Claim 1

A DIRECTIONAL CONDENSER MICROPHONE FOR TRANSMITTING A PREDETERMINED FREQUENCY RANGE; COMPRISING AT LEAST ONE DIAPHRAGM HAVING FRONT AND REAR FACES WITH A MINIMUM AREA OF 10 SQUARE CENTIMETERS AND A MAXIMUM DIMENSION SUBSTANTIALLY LARGER THAN THE WAVELENGTH OF THE HIGHEST FREQUENCY OF SAID RANGE, BOTH OF SAID FACES BEING EXPOSED TO THE ACTION OF THE SOUND FIELD; SUPPORT MEANS CARRYING SAID DIAPHRAGM; MEANS CONSTITUTING A FRICTIONAL ACOUSTIC RESISTANCE; SAID SUPPORT MEANS, SAID REAR FACE OF THE DIAPHRAGM AND SAID MEANS CONSTITUTING A FRICTIONAL ACOUSTIC RESISTANCE DEFINING A CAVITY; AND SAID CAVITY AND SAID FRICTIONAL ACOUSTIC RESISTANCE BEING OPERATIVE AS A PHASE-SHIFTING ELEMENT ONLY UP TO A PREDETERMINED FREQUENCY IN SAID RANGE AT WHICH ONE-HALF OF THE WAVELENGTH OF SOUND IS LESS THAN THE EFFECTIVE LENGTH OF THE SOUND PATH FROM THE CENTER OF SAID FRONT FACE OF THE DIAPHRAGM AROUND THE MICROPHONE TO THE CENTER OF SAID REAR FACE OF THE DIAPHRAGM.