Abstract: An active noise reduction (ANR) earphone system includes a feedback microphone for detecting noise, feedback circuitry, responsive to the feedback microphone, for applying a digital filter Kfb to an output of the feedback microphone to produce an antinoise signal, an electroacoustic driver for transducing the antinoise signal into acoustic energy, a housing supporting the feedback microphone and the driver near the entrance to the ear canal, and an ear tip for coupling the housing to the external anatomical structures of a first ear of a user and positioning the housing to provide a consistent acoustic coupling of the feedback microphone and the driver to the ear canal of the first ear. The acoustic coupling includes a tube of air defined by the combination of the housing and ear tip, having a length L and effective cross-sectional area A such that the ratio L/A is less than 0.6 m?1.

Abstract: An apparatus include a first electronic component having first interface circuitry configured to generate an electromagnetic signal. The first electronic component is switchable such that in a first mode of operation, the first interface circuitry is configured to transmit the generated electromagnetic signal via a first antenna, and in a second mode of operation, the first interface circuitry is configured to transmit the electromagnetic signal to a second electronic component via a constrained signal path coupling the first electronic component and the second electronic component. The generated electromagnetic signal may be a radio frequency signal or an optical signal.

Abstract: A detecting circuit measures at least one response characteristic of an output channel in an electro-acoustic transducer system. A memory stores a plurality of equalizations, each equalization corresponding to a known electro-acoustic transducer system associated with at least one response characteristic stored in the memory. A processor in communication with the detecting circuit and the memory selects one of the stored response characteristics matching the response characteristic measured by the detecting circuit. In some cases, an appropriate equalization is loaded based on the selected response characteristic.

Abstract: An apparatus include a first electronic component having first interface circuitry configured to generate an electromagnetic signal. The first electronic component is switchable such that in a first mode of operation, the first interface circuitry is configured to transmit the generated electromagnetic signal via a first antenna, and in a second mode of operation, the first interface circuitry is configured to transmit the electromagnetic signal to a second electronic component via a constrained signal path coupling the first electronic component and the second electronic component. The generated electromagnetic signal may be a radio frequency signal or an optical signal.

Abstract: A detecting circuit measures at least one response characteristic of an output channel in an electro-acoustic transducer system. A memory stores a plurality of equalizations, each equalization corresponding to a known electro-acoustic transducer system associated with at least one response characteristic stored in the memory. A processor in communication with the detecting circuit and the memory selects one of the stored response characteristics matching the response characteristic measured by the detecting circuit. In some cases, an appropriate equalization is loaded based on the selected response characteristic.