The boundary layer microphone shall have a hypercardioid pattern and shall fit within a rectangular envelope given by: 97 x 67 x 20 mm (3.9 x 2.6 x 0.8 in.). The sensitivity shall be no lower than 30 mV/Pa, and total harmonic distortion (THD) at an operating level of 115 dB shall be no greater than 1 %. The equivalent noise level shall be no greater than 27 dB-A. The frequency response shall be flat from 60–20,000 Hz. The microphone shall operate on phantom power over the range from 9 to 52 volts dc. Net/shipping weight: 100/400 g (3.5/14.1 oz.).
