Personal communication method and apparatus with acoustic stray field cancellation

Abstract

Personal communication method and apparatus, such as telephone handsets and headsets, with acoustic stray field cancellation are disclosed. The personal communications device employs an echo canceling receiver generally including two displacement sources that are not in phase formed by at least one driver, an acoustic cavity corresponding to each displacement source, and an acoustic output port corresponding to and in acoustic connection with each displacement source via the corresponding acoustic cavity such that the acoustic length between the acoustic centers of the two ports is less than the distance between the acoustic center of each port and the acoustic center of the corresponding displacement source to which the port is acoustically connected. In another embodiment, the ports may be such that both ports are located on a same side of a surface of at least one of the displacement sources. As an example, the personal listening device may have at least two ports and a dedicated driver acoustically coupled to each port. The personal communication device may further include a transmit module. The ports may be driven and tuned such that when the device is worn, the ratio of acoustic pressure at a first location, e.g., the ear, to acoustic pressure at a second location, e.g. the transmit module, is substantially greater than that with either port acting alone. In another embodiment, the receiver ports are driven and tuned such that when the device is worn, the ratio of acoustic pressure at the first location to sound pressure gradient in a given direction at the second location is substantially greater than that with either port acting alone. The receiver thus achieves echo canceling for high frequencies.