Abstract: An earphone has a casing, containing a speaker, the casing being adapted to fit within the outer ear of a user at the entrance to the ear canal of the user. The casing has a guide, protruding from the front surface of the casing, and suitable for locating in the ear canal of the user. The casing is also adapted to allow sound to pass through a sound-permeable portion of the front surface. The casing has sound channels, leading across the front surface of the casing from the sound-permeable portion to a periphery of the first surface of the casing. The earphone can be used in a noise cancelling earphone system, with signal processing circuitry connected to the microphone and to the speaker, wherein the signal processing circuitry is adapted to receive the ambient noise signal from the microphone, and to apply the ambient noise signal to a filter having a controllable amount of gain, for generating a noise cancellation signal for transmission to the speaker.

Abstract: An earphone has a housing, with a speaker mounted within the housing. A cable inlet contains a cable that includes a wire connected to the speaker. The cable and the cable inlet have different cross-sectional shapes, such that the cable is in contact with the inner surface of the cable inlet over a substantial portion of their length, while a rear volume of the speaker is vented through the cable inlet. This ensures that the cross-sectional area through which the rear volume is vented through the cable inlet remains relatively constant. The earphone may further comprise a microphone, positioned to detect ambient noise approaching the ear of a wearer of the earphone, and the cable may then further include a wire connected to the microphone.

Abstract: An earphone comprises an earphone body, containing a speaker, and a projection, extending from a first surface of the earphone body, for location in the entrance to the user's ear canal. The earphone body comprises a sound outlet in the first surface, for allowing sounds generated by the speaker to leave the earphone body. The projection extends from the first surface of the earphone body, adjacent to the sound outlet, and contains a sound inlet port, connected to a microphone for detecting sounds entering the ear canal. A noise cancellation system includes noise cancellation circuitry, for applying a frequency dependent filter characteristic and applying a gain to an input signal representing ambient noise, at least one of the frequency dependent filter characteristic and the gain being adaptive. The earphone then has an ambient noise microphone, and an error microphone connected to the sound inlet port.

Abstract: An earphone has a housing, with a speaker mounted within the housing. A cable inlet contains a cable that includes a wire connected to the speaker. The cable and the cable inlet have different cross-sectional shapes, such that the cable is in contact with the inner surface of the cable inlet over a substantial portion of their length, while a rear volume of the speaker is vented through the cable inlet. This ensures that the cross-sectional area through which the rear volume is vented through the cable inlet remains relatively constant. The earphone may further comprise a microphone, positioned to detect ambient noise approaching the ear of a wearer of the earphone, and the cable may then further include a wire connected to the microphone.

Abstract: An earphone has a casing, containing a speaker, the casing being adapted to fit within the outer ear of a user at the entrance to the ear canal of the user. The casing has a guide, protruding from the front surface of the casing, and suitable for locating in the ear canal of the user. The casing is also adapted to allow sound to pass through a sound-permeable portion of the front surface. The casing has sound channels, leading across the front surface of the casing from the sound-permeable portion to a periphery of the first surface of the casing. The earphone can be used in a noise cancelling earphone system, with signal processing circuitry connected to the microphone and to the speaker, wherein the signal processing circuitry is adapted to receive the ambient noise signal from the microphone, and to apply the ambient noise signal to a filter having a controllable amount of gain, for generating a noise cancellation signal for transmission to the speaker.

Abstract: An earphone has a casing, containing a speaker, the casing being adapted to fit within the outer ear of a user at the entrance to the ear canal of the user. The earphone can be used in a noise cancelling earphone system, with signal processing circuitry connected to the microphone and to the speaker. The signal processing circuitry is adapted to receive the ambient noise signal from the microphone, and to apply the ambient noise signal to a filter having a controllable amount of gain, for generating a noise cancellation signal for transmission to the speaker. The result is that, however the earphone is worn within the outer ear of a user, an amount of sound leakage lies within a predetermined range, such that the amount of gain to be applied by the signal processing circuitry falls within a relatively narrow range.