Abstract: Measurements of body sounds in the ear canal may be used for many applications. However, reliability is dependent on the ear canal being properly sealed to allow the body sounds to achieve a detectable level. An apparatus is therefore provided for determining a seal quality indication for a seal of an ear canal. An ear canal microphone (201) provides a microphone signal to an input (203) which is coupled to a circuit (205) for generating a first signal from the microphone signal. The first signal may be the same as the microphone signal. A circuit (209) then determines the seal quality in response to the frequency spectrum for the first signal. A frequency transformer (207) may perform a frequency transformation on the first signal to generate a frequency spectrum for the first signal and. The seal quality indication may specifically be generated based on a detection of a low frequency boost.

Abstract: An earphone arrangement comprises a microphone (109) which generates a microphone signal and a sound transducer (101) which radiates a first sound component to a user's ear (103) in response to a drive signal. An acoustic channel (111) is further provided for channeling external sound so as to provide a second sound component to the user's ear (103). An acoustic valve (117) allows the attenuation of the acoustic channel (111) to be controlled in response to a valve control signal. A control circuit (105) generates the valve control signal in response to the microphone signal to provide a variable attenuation resulting in a mixed sound of the first sound component and the second sound component reaching the user's ear (103). The combined use of acoustic and e.g. electric signal paths allows improved performance and in particular allows a dynamic trade-off between open and closed earphone design characteristics with respect to external sounds.

Abstract: An earphone arrangement comprises a microphone (109) which generates a microphone signal and a sound transducer (101) which radiates a first sound component to a user's ear (103) in response to a drive signal. An acoustic channel (111) is further provided for channeling external sound so as to provide a second sound component to the user's ear (103). An acoustic valve (117) allows the attenuation of the acoustic channel (111) to be controlled in response to a valve control signal. A control circuit (105) generates the valve control signal in response to the microphone signal to provide a variable attenuation resulting in a mixed sound of the first sound component and the second sound component reaching the user's ear (103). The combined use of acoustic and e.g. electric signal paths allows improved performance and in particular allows a dynamic trade-off between open and closed earphone design characteristics with respect to external sounds.