Abstract: The system eliminates the noise, rumble and hiss from any standard 35 mm analog optical sound track. By simply feeding the film through the projector sound head in a normal manner the system automatically converts the analog optical sound tracks to digital quality. No special storing of digital data on film is required and no special digital decoder equipment is needed. The system produces noise-free sound, increased frequency response, expanded dynamic range and clarity of the dialogue. Film studios will no longer need to carry a double inventory of films having digital and analog sound tracks or to process the sound tracks for noise reduction.

Abstract: An arrangement of divergently mounted acoustic transducers in a hemispherical air tight enclosure, the enclosure being sized with regard to the loading requirements of the acoustic transducers to produce a small size speaker system having an omnidirectional sound radiation pattern and a flat frequency response without the need of a crossover network. The hemispherical enclosure being comprised of six flat equal sided pentagonal plates, five triangular shaped flat gussets and a flat base plate all of which when assembled forms a half dodecahedron polyhedron shaped enclosure with a closed base, with the base serving as the enclosure mounting surface.