A sound pickup device, which is arranged in proximity to a percussion instrument (e.g., a bass drum), comprises a diaphragm stretched under tension over an opening of a shell having a cylindrical shape, and an electroacoustic transducer arranged inside of the shell. The electroacoustic transducer comprises...http://www.google.fr/patents/US7256342?utm_source=gb-gplus-shareBrevet US7256342 - Sound pickup device for percussion instrument
