A system may include a first input for receiving a first signal for driving an amplifier that drives a load, a second input for receiving a second signal driven by the amplifier, and an instability detector for detecting instability of a feedback loop for controlling the first signal based on comparison of the first signal and the second signal.

A system may include a first input for receiving a first signal for driving an amplifier that drives a load, a second input for receiving a second signal driven by the amplifier, and an instability detector for detecting instability of a feedback loop for controlling the first signal based on comparison of the first signal and the second signal.

Acoustic loudspeaker (10) comprising a cabinet (12) extending in a direction (L), and a speaker (14) defining an acoustic axis (X). The cabinet defines a first axis (V1) perpendicular to the direction, and a second axis (V2) perpendicular to the direction and to the first axis.

The acoustic loudspeaker is intended to be used in a first configuration, wherein the first axis is essentially vertical, and a second configuration, wherein the second axis is essentially vertical.

The speaker is movable relative to the cabinet around an axis of rotation (D) between a first position, wherein the acoustic axis defines with the second axis a first angle less than 30°, and a second position, in which the acoustic axis defines with the first axis (V1) a second angle less than 30°. The axis of rotation makes two angles between 40° and 50° with the first axis and the second axis.

A display apparatus includes a display panel configured to display an image and including a first to a fifth regions, at least one first and fourth sound generating devices in a left region of a rear surface of the display panel and in the first and fourth regions, at least one second and fifth sound generating device in a right region of the rear surface and in the second and fifth regions, and at least one third sound generating device in a center region of the rear surface and in the third region. The at least one first to third sound generating devices is configured to vibrate the display panel to generate sound, and the at least one fourth and fifth sound generating devices is configured to vibrate the display panel to generate sound in a direction upwards from the display panel.

A display apparatus includes a display panel configured to display an image and including a first to a fifth regions, at least one first and fourth sound generating devices in a left region of a rear surface of the display panel and in the first and fourth regions, at least one second and fifth sound generating device in a right region of the rear surface and in the second and fifth regions, and at least one third sound generating device in a center region of the rear surface and in the third region. The at least one first to third sound generating devices is configured to vibrate the display panel to generate sound, and the at least one fourth and fifth sound generating devices is configured to vibrate the display panel to generate sound in a direction upwards from the display panel.

A detection system includes a drill bit where electro-acoustic transducers operate as a transmitter and/or receiver, are integrated; electronic circuits; a control unit associated with a data storage unit and is powered by an electrical supply system, the processing and control unit for generating driving signals sent to the electro-acoustic transducer acting as a transmitter by the analogue driving electronic circuits, for acquiring signals received from the transducer and for processing the received signals to determine discontinuity interfaces and/or anomalies in pore pressures in geological formations; wherein each of the electro-acoustic transducers is in contact with a pressurised fluid and includes: a tubular body with two end portions opposed to each other longitudinally, internally a first chamber with the first end portion and a second chamber on one side adjacent and in fluid communication with the first chamber and, on the other side ending with the second end portion.

A display device, includes: a display panel including a pixel array layer, a panel lower member disposed under the display panel, a first magnet disposed under the panel lower member and having a first area, a vibration generator coupled to one surface of the first magnet and having a second area larger than the first area; and a second magnet overlapping the first magnet in a thickness direction and spaced apart from the first magnet in the thickness direction.

A display device, includes: a display panel including a pixel array layer, a panel lower member disposed under the display panel, a first magnet disposed under the panel lower member and having a first area, a vibration generator coupled to one surface of the first magnet and having a second area larger than the first area; and a second magnet overlapping the first magnet in a thickness direction and spaced apart from the first magnet in the thickness direction.

The invention provides apparatus and methods for interference based wave synthesis. The invention comprises (i) receiving information defining output wave characteristics, said output wave characteristics comprising at least an output wave frequency B, and an output signal amplitude M, (ii) determining a constant value A and (iii) driving a first input wave generator to generate a first input wave and (iv) driving a second input wave generator to generate a second input wave, such that the interfered wave synthesized by interference of the first input wave and the second input wave has output wave characteristics defined by the received information.

A speaker comprises a housing, a transducer residing inside the housing, and at least one sound guiding hole located on the housing. The transducer generates vibrations. The vibrations produce a sound wave inside the housing and cause a leaked sound wave spreading outside the housing from a portion of the housing. The at least one sound guiding hole guides the sound wave inside the housing through the at least one sound guiding hole to an outside of the housing. The guided sound wave interferes with the leaked sound wave in a target region. The interference at a specific frequency relates to a distance between the at least one sound guiding hole and the portion of the housing.