An external ear canal pressure regulation device including a fluid flow generator and an earpiece having a first axial earpiece conduit fluidicly coupled to the fluid flow generator, whereby the earpiece has a compliant earpiece external surface configured to sealably engage an external ear canal as a barrier between an external ear canal pressure and an ambient pressure.

An external ear canal pressure regulation device including a fluid flow generator and an earpiece having a first axial earpiece conduit fluidicly coupled to the fluid flow generator, whereby the earpiece has a compliant earpiece external surface configured to sealably engage an external ear canal as a barrier between an external ear canal pressure and an ambient pressure.

The microphone comprises a housing (1, 2), which has an inner volume (12) filled with a gas, an opening (10) of the housing, an acoustic sensor (3) arranged in the housing, a diaphragm (13) of the acoustic sensor located above the opening, and a heater (14) in the inner volume. The acoustic sensor may especially comprise a microelectromechanical system. The gas is heated from inside the inner volume to increase the pressure and generate a corresponding signal of the acoustic sensor (3). This signal can be used for self-calibration of the sensitivity or for self-diagnostics to check the function of the microphone.

The microphone comprises a housing (1, 2), which has an inner volume (12) filled with a gas, an opening (10) of the housing, an acoustic sensor (3) arranged in the housing, a diaphragm (13) of the acoustic sensor located above the opening, and a heater (14) in the inner volume. The acoustic sensor may especially comprise a microelectromechanical system. The gas is heated from inside the inner volume to increase the pressure and generate a corresponding signal of the acoustic sensor (3). This signal can be used for self-calibration of the sensitivity or for self-diagnostics to check the function of the microphone.

An airtight tensionally stiff speaker diaphragm (i.e. being non-stretch, having a relatively high Young's modulus) which relies on tensile stiffness and air pressure to maintain its shape and produce sound can be extremely lightweight, a lighter spider is also described.

Apparatus and methods for the measurement of gas volume fraction of produced oil are described. A first method measures the response of a pipe containing the produced oil excited by a source of vibration in the form of an acoustic frequency chirp containing a linearly varying range of frequencies in the tens of kilohertz range encompassing at least one resonant mode of the pipe. As the gas volume fraction increases, the location of the peak maximum of the measured frequency spectrum responsive to the excitation increases in frequency, and the height of the peak maximum increases, thereby permitting a linear calibration curve to be obtained. A second method measures the response of a pipe containing the produced oil to excitation by a continuous source of vibration having a chosen frequency above those which excite flexural vibrations in the pipe and simultaneously excite acoustic waves in the fluid contained in the pipe, known as the coincidence frequency. Gas present in the fluid will interrupt sound propagation or reverberation, thereby generating fluctuations in the amplitude of the measured vibrations of the pipe. The amplitude fluctuation level provides a measure of the gas volume present inside the pipe. A third method measures the response of a pipe containing the produced oil to excitation by a high-bandwidth, short pulse having a chosen center frequency above the coincidence frequency. Gas present in the fluid will interrupt pulse propagation, thereby generating fluctuations in the amplitude of the measured vibrations of the pipe.

Apparatus and methods for the measurement of gas volume fraction of produced oil are described. A first method measures the response of a pipe containing the produced oil excited by a source of vibration in the form of an acoustic frequency chirp containing a linearly varying range of frequencies in the tens of kilohertz range encompassing at least one resonant mode of the pipe. As the gas volume fraction increases, the location of the peak maximum of the measured frequency spectrum responsive to the excitation increases in frequency, and the height of the peak maximum increases, thereby permitting a linear calibration curve to be obtained. A second method measures the response of a pipe containing the produced oil to excitation by a continuous source of vibration having a chosen frequency above those which excite flexural vibrations in the pipe and simultaneously excite acoustic waves in the fluid contained in the pipe, known as the coincidence frequency. Gas present in the fluid will interrupt sound propagation or reverberation, thereby generating fluctuations in the amplitude of the measured vibrations of the pipe. The amplitude fluctuation level provides a measure of the gas volume present inside the pipe. A third method measures the response of a pipe containing the produced oil to excitation by a high-bandwidth, short pulse having a chosen center frequency above the coincidence frequency. Gas present in the fluid will interrupt pulse propagation, thereby generating fluctuations in the amplitude of the measured vibrations of the pipe.

The present disclosure provides a reliable structure which can prevent disconnection of a voice coil lead wire, while employing a voice coil embodied as an aluminum coil to improve the mid-frequency band SPL of a slim high-pressure water resistant microspeaker. According to the present disclosure, there is provided a high-pressure water resistant microspeaker with an improved coil structure, including an FPCB attached to the outer surface of a frame, a pad of the FPCB extending inside the frame and another part of the FPCB extending outside the frame. The upper end of the voice coil is attached to an overlapping position of a side diaphragm and a center diaphragm, and the lower end of the voice coil is supported by the part of the FPCB extending inside the frame.

The present disclosure provides a reliable structure which can prevent disconnection of a voice coil lead wire, while employing a voice coil embodied as an aluminum coil to improve the mid-frequency band SPL of a slim high-pressure water resistant microspeaker. According to the present disclosure, there is provided a high-pressure water resistant microspeaker with an improved coil structure, including an FPCB attached to the outer surface of a frame, a pad of the FPCB extending inside the frame and another part of the FPCB extending outside the frame. The upper end of the voice coil is attached to an overlapping position of a side diaphragm and a center diaphragm, and the lower end of the voice coil is supported by the part of the FPCB extending inside the frame.

Techniques are disclosed relating to sensors configured to measure acceleration and pressure. In various embodiments, an apparatus includes a first hydrophone sensor having a first piezoelectric material and a first housing structure and a second hydrophone sensor having a second piezoelectric material and a second housing structure. In some embodiments, the apparatus includes a first pair of wires configured to provide a first differential voltage and a second pair of wires configured to provide a second differential voltage. The first pair of wires may be coupled to the first hydrophone sensor and the second pair of wires may be coupled to the second hydrophone sensor. In various embodiments, the apparatus is configured to determine, based on the first and second differential voltages, a pressure and an acceleration experienced by the first and second hydrophone sensors.