An ultrasonic energy gathering device and an ultrasonic repeller using the ultrasonic energy gathering device are provided. The ultrasonic energy gathering device includes an energy gathering part. The energy gathering part has a trapezoidal cross section. The energy gathering part is provided with a gathering port and a diffusing port. The gathering port is smaller than the diffusing port. The ultrasonic energy gathering device further includes an ultrasonic fixing part. The ultrasonic fixing part fixes the ultrasonic energy gathering device with an ultrasonic transmitter of an ultrasonic repeller, so that an ultrasonic wave transmitted from the ultrasonic transmitter enters the gathering port to be gathered and strengthened, and the coverage of the ultrasonic wave gradually expands along the direction away from the diffusing port under the action of the ultrasonic energy gathering device.

The invention discloses a novel passive sound transformer, either a sound-booster or a sound-silencer, embodied as an acoustic waveguide, a specific shape of which provides for either amplifying the intensity of acoustic waves at the expense of both the heat energy and the concomitant turbulence of moving fluid wherein the amplified intensity of the acoustic waves is manifested as sound loudness boosting or, contrarywise, transforming the wave power of elastic waves into the heat of the ambient fluid.

A waveguide assembly for a loudspeaker is provided. The waveguide assembly includes a plurality of panels and a plurality of trays, which together at least partially defines a waveguide. One or more of the panels are arranged to be movable relative to the trays to adjust a coverage pattern of the waveguide.

A loudspeaker comprising: an acoustic diaphragm having front and rear surfaces, the acoustic diaphragm in use being driven so as to vibrate and radiate acoustic waves from its front surface in a forward direction away from the loudspeaker and from its rear surface in a rearward direction, and a drive unit located rearwardly or to the front/outside of the diaphragm, there being at least one open duct leading in a rearward direction away from the diaphragm, in which the at least one open duct has a cross-sectional area which decreases in the rearward direction, and in which acoustic waves radiated from the rear surface of the diaphragm pass through the open duct before contacting a front surface of an acoustic metamaterial absorber located generally behind the drive unit and immediately to the rear of the duct.

Supercoupling power dividers are provided, in which acoustic impedance at an acoustic input port matches the combined acoustic impedance at two or more acoustic output ports, and the phase of the input signal matches the combined phases of the two or more acoustic output ports. Methods for achieving impedance matching using a uniform-phase acoustic power divider are also provided. The devices and methods achieve acoustic supercoupling without requiring embedded membranes or resonators.

A waveguide assembly for a loudspeaker is provided. The waveguide assembly includes a plurality of panels and a plurality of trays, which together at least partially defines a waveguide. One or more of the panels are arranged to be movable relative to the trays to adjust a coverage pattern of the waveguide.

Defining critical spacing is necessary for steering of parametric audio. Comparing steering measurements both with and without a waveguide leads to a conclusion that the diffuse phyllotactic grating lobe contributes audio and is to blame for poor steering. In addition, the waveguide needs to function with correct phase offsets to achieve the steering required for performance. Arranging tubes so that the array configuration changes from rectilinear to another distribution is useful when the waveguide is short of critical spacing or constrained for space. Array designs may also capitalize on rectilinear transducer design while having the benefits of a transducer tiling that has irrational spacing to promote the spread of grating lobe energy.

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.

A speaker system including an enclosure, a first acoustic driver engaged with the enclosure, and two or more horns configured to output a sound from the first acoustic driver to a front plane of the enclosure. In one embodiment, the two or more horns may be folded and planar. In one embodiment, the speaker system may include a second acoustic driver, which may be installed above or below the first acoustic driver. The second acoustic driver may be larger or smaller or the same size when compared to the first acoustic driver.

One embodiment provides a waveguide for controlling sound directivity of high frequency sound waves generated by a speaker driver. The waveguide is positioned in front of the speaker driver. The waveguide comprises one or more ridge areas, one or more recess areas, and one or more smooth surfaces. Each smooth surface connects a ridge area to a recess area to create a smooth transition between the ridge area and the recess area without any seams or sharp transitions. The waveguide shapes propagation of the sound waves to provide a smooth off-axis frequency response for the sound waves.