US Patent 8472639 Microphone arrangement having more than one pressure gradient transducer

A microphone arrangement includes multiple pressure gradient transducers having an acoustic center, a first sound inlet opening leading to a front of a diaphragm, and a second sound inlet opening leading the back of the diaphragm. A directional characteristic of the pressure gradient transducers includes an omni portion and a figure-eight portion. The pressure gradient transducers have a direction of maximum sensitivity in a main direction. Each main direction of the pressure gradient transducers is inclined. The acoustic center of a pressure transducer and the pressure gradient transducers are positioned within an imaginary sphere having a radius that corresponds to double the largest dimension of the diaphragm of one of the transducers.