Neumann KMR 81I Shotgun MicrophoneThe KMR 81 i Shotgun Microphone from Neumann uses a combination of a pressure gradient transducer and an interference tube. If the wavelength of the frequency is longer than the tube length, the microphone works as a pressure gradient transducer. At higher frequencies, it operates as an interference transducer for lateral sound. Off axis sound sources are picked up with reduced level, but without coloration. Therefore, the microphone is well suited to