US Patent 9838787 Acoustic device

An acoustic device that is adapted to be worn on the body of a user, with a first acoustic transducer and a second acoustic transducer, where the first transducer is closer to the expected location of a first ear of the user than is the second transducer, a third acoustic transducer and a fourth acoustic transducer, where the third transducer is closer to the expected location of a second ear of the user than is the fourth transducer, and a controller that is adapted to independently control the phase and frequency response of the first, second, third and fourth transducers.