BM6 was a pressure-gradient ribbon microphone with full-frequency range, perfect figure-eight directional characteristic and a 3-position switch for speech, music and off. It had an international standard plug (DIN) and 150-ohm impedance – the internationally-accepted impedance for dynamic microphones in recording studios. Adding the BM7 microphone converted the BM6 into the BM5 mono/stereo microphone which could be use for stereo recordings according to the MS or AB method as desired.