A directional sound apparatus includes a planar shape plate and a sound wave generator. The planar shape plate has a plurality of grooves formed on a surface of the planar shape plate. The sound wave generator is configured to radiate a sound wave to outside from the surface of the planar shape plate. A width of each of the grooves and a distance between the grooves adjacent to each other are smaller than a wavelength of the sound wave. The planar shape plate has a plurality of cell areas in which at least one groove is included. A structure of the groove included in a first cell area is different from that of the groove included in a second cell area adjacent to the first cell area, so that surface admittance in the first cell area is different from that in the second cell area.

A directional sound apparatus includes a planar shape plate and a sound wave generator. The planar shape plate has a plurality of grooves formed on a surface of the planar shape plate. The sound wave generator is configured to radiate a sound wave to outside from the surface of the planar shape plate. A width of each of the grooves and a distance between the grooves adjacent to each other are smaller than a wavelength of the sound wave. The planar shape plate has a plurality of cell areas in which at least one groove is included. A structure of the groove included in a first cell area is different from that of the groove included in a second cell area adjacent to the first cell area, so that surface admittance in the first cell area is different from that in the second cell area.

Electroacoustic device that includes a body, an electrode to be electrically powered, named hot electrode, and an electrode to be electrically grounded, named ground electrode. The body includes a piezoelectric part or the electroacoustic device further including a piezoelectric part different from the body. The hot electrode includes a hot track spiraling around a spiral axis. The radial step between two consecutive coils of the hot track decreasing radially from the spiral axis. The hot electrode and the ground electrode are arranged on the piezoelectric part such as to define a wave transducer configured to generate a focalised ultrasonic vortex propagating in the body and/or, when a fluid medium is acoustically coupled with the electroacoustic device, in the fluid medium.

In the sound insulation apparatus, a sound wave transmitter configured to transmit sound waves with frequencies including the frequencies of propagation sound waves from a sound source and a sound wave receiver configured to receive the sound waves transmitted from the sound wave transmitter are coupled such that the orientation of a sound wave transmission surface of the sound wave transmitter and the orientation of a sound wave receiving surface of the sound wave receiver intersect each other and one pair set is formed. The one pair set is disposed in plurality such that the sound wave transmission surface of one set is spaced from and opposed to the sound wave receiving surface of another set and a space surrounding the sound source is formed. The sound waves transmitted from each of the sound wave transmitters are mixed with the propagation sound waves.

A transducer probe includes a transducer array with rows of transducer elements that each extend in an elevation direction and is transverse to an azimuth direction, a matching layer disposed adjacent to the transducer array, and a focusing layer disposed adjacent to the matching layer. The focusing layer includes a first material with a first refractive index and a second material with a second refractive index, and the first refractive index is less than the second refractive index. The first and second materials are distributed in an alternating pattern with the first material at edges of the rows. First widths of the first material decrease from the edges towards a center of the rows, and second widths of the second material increase from the edges towards the center.

An acoustic structure for beaming soundwaves from a first direction toward a second direction, may include a plurality of phononic crystals. The plurality of phononic crystals have an outer border, an internal cavity and a channel extending between the outer border and the internal cavity, wherein the channel defines an opening within the outer border. The phononic crystals are disposed such that the opening faces the second direction. Soundwaves from the first direction are beamed to the second direction by the plurality of phononic crystals.

An acoustic structure for beaming soundwaves from a first direction toward a second direction, may include a plurality of phononic crystals. The plurality of phononic crystals have an outer border, an internal cavity and a channel extending between the outer border and the internal cavity, wherein the channel defines an opening within the outer border. The phononic crystals are disposed such that the opening faces the second direction. Soundwaves from the first direction are beamed to the second direction by the plurality of phononic crystals.

An acoustic system for an Urban Air Mobility (UAM) vehicle may comprise a first shield configured to be disposed around a rotor of the UAM vehicle, the first shield having an annular shape, the first shield configured to be disposed radially outward from a blade tip of a rotary blade, the first shield configured to redirect sound waves from a substantially radial direction to a second direction, the second direction being orthogonal to the radial direction.

The present disclosure relates to a sonar device (1) for detection of underwater objects. The sonar device comprises a body element (2) having a cavity. A piezo electric element (3) is comprised within the cavity. A resin filling (6) of the cavity protects the piezo electric element (3) from water at underwater operation. The sonar device further comprises a holder (4) adapted to hold the piezo electric element (3). The holder (4) is arranged to centre and hold the piezo electric element (3) within said body element (2). The holder (4) comprises in its structure a plurality of damping structures (5). A method of manufacturing holder and a sonar device is also disclosed.

A method of designing an acoustic waveguide in which acoustic waves travelling along the waveguide are treated as exhibiting single parameter behaviour, and in which the waveguide provides a boundary confining the acoustic waves as they travel along the wave propagation path and has two substantially parallel, primary surfaces spaced apart a distance less than a wavelength of a high frequency acoustic wave. The primary surfaces may be planar, curved, or a combination of planar portions and curved portions.