GFM 132

Common name: Neumann GFM 132

Production Status: Discontinued / Vintage

The GFM 132 is the only boundary layer microphone manufactured by Georg Neumann GmbH from 1990 to 2012. A new pressure capsule (K 32) with a MCF (Pe/G) diaphragm is placed on top of an aluminium made plate, suitable to be installed on a sound reflecting surface like a table, a floor or a wall. The reflecting surface, if larger than the incoming sound wavelength increases the sound pressure. The GMF 132 is designed to achieve 6 dB increase for frequencies above 1,5 kHz in a free sound field. When placed on a large surface, lower frequencies are increased by the surface itself, so the microphone system has a virtually frequency-independent hemispherical directional pattern in addition to 6 dB with higher sensitivity. The GMF 132 body shape is engineered, via advanced computer modelling, to eliminate vertical and horizontal sound coloration. The frequency response is the same for both free and diffuse sound fields, with no sound coloration for moving sound sources (e.g. actors across the stage). Moreover GMF 132 microphones do not produce comb filtering in multi-miking applications and therefore can be used for A-B stereo setups in rooms with good acoustical properties. The physical theory regarding use and application of a boundary layer microphones vs. conventional microphones design is quite complicated. Please refer to M. Schneider and B. Muller’s AES papers and to Neumann GMF 132 operating instructions for further information.