US Patent 7362876 Interference-free transmitting receiving earset

A interference-free transmitting receiving earset includes a housing houses a speaker, a grille covering the speaker and having a front center tube, and two microphones mounted in the center tube of the grille in reversed directions to pick up sound waves from the user's external auditory canal and wound waves from the speaker respectively and to eliminate interference of sound waves from the speaker with sound waves produced by the user in the external auditory canal.