C562 CM - Hemi-spherical A 'professional,flush-mount, boundary microphone', designed for permanent, 'invisible' mounting in ceilings, walls, tables and stages, the C562 CM is characterised by 'excellent clarity and a consistent pickup anywhere around' the microphone, styled by AKG as the 'Invisible ear' for recording, courtroom, surveillance and security applications and a 'perfect tool for surveillance or live recording'. It has a hemi-spherical polar pattern for 'clear, intelligible pickup of speech'. 'high sensitivity for a great pickup area' and a 'low-profile cylindrical design perfect for wall or tabletop installation'. Note that since this microphone has a hemi-spherical pattern, it receives sound at an equal level from all directions except through the base of the plate. As a result it could be very useful for a round-table discussion or mounted on a wall, but in neither of these cases if it is feeding a loudspeaker which is within the range of that hemisphere. The microphone is meant to be mounted through a sheet of material or a plate. A 3mm thick, 20mm diameter, bevelled disc sits on the surface of the plate, showing only four drilled holes in the matt nickel-plated surface. Behind this, a threaded cylinder fits through a 12.5mm hole in the plate, held in position by a milled nut. The cylinder is 25mm in length, and contains the electret capsule and a cable grip for the captive cable which exits from the cylinder at the rear. This cable is 500mm long, terminated with a two pole miniature jack plug, which is small enough to go through the mounting hole. The plug mates with a cable socket with 500mm of cable, connected to an extended-length XLR connector containing a phantom power adapter. Output connector: 3-pin, male XLR. Applications: Recording, courtroom, surveillance and security applications. Response: 20Hz-20kHz. Sensitivity: 25mV/Pa. Phantom power: 9-52V DC. Dimensions: 3 x 20(depth x diameter) mm plate;.25 x 12(depth x diameter) mm rear cylinder. Weight: 30g without cable. Boundary Microphones When a microphone diaphragm is placed very close to a flat surface it is said to be in the 'pressure zone' or at the acoustical boundary of the room. This is the region where any reflections of acoustic waves will be so short that they will have a frequency way above the range of human hearing, thus avoiding the comb-filtering, or interference of the direct sound by the reflected sound, experienced when placing a normal microphone near a reflective surface. Excelent condition. Length total 103 cm. Not have box. Only can see on photos. Made in Austria,original microphone.