An electronic horn includes a cover (8) on a front side of an intermediate element (6). A first passage (P1) within the horn is defined by a central portion (82) of the cover (8) that projects into a cylindrical interior of a cylindrical water-proofing wall (621). Second passages (P2, P3, P4) extend generally concentrically with respect to the first passage (P1) and are respectively defined by water-proofing walls (83, 84) that are formed on the cover (8) and project into the interior spaces of water-proofing walls (622, 633). The outermost second passage (P4) opens toward the forward direction. The first and second passages (P1-P4) extend in a back-and-forth path that prevents any rainwater, which has entered the interior of the horn through the opening of the outermost second passage (P4), from reaching a resonance space (7) defined between the resonator (7) and a sound-generating oscillator (51).

A resonance tube of a horn according to one aspect of the present invention includes a first resonance tube and a second resonance tube branching from the first resonance tube at a branching portion. The first resonance tube is a resonance tube that resonates with a first sound contained in a chord generated by a diaphragm. The first resonance tube includes: an input opening surface to which the chord is input; and a first opening surface from which the first sound is output. The second resonance tube is a resonance tube that resonates with a second sound contained in the chord. The second resonance tube includes a second opening surface from which the second sound is output. The second opening surface is displaced from the first opening surface in a normal direction K1.

A resonance tube of a horn according to one aspect of the present invention includes a first resonance tube and a second resonance tube branching from the first resonance tube at a branching portion. The first resonance tube is a resonance tube that resonates with a first sound contained in a chord generated by a diaphragm. The first resonance tube includes: an input opening surface to which the chord is input; and a first opening surface from which the first sound is output. The second resonance tube is a resonance tube that resonates with a second sound contained in the chord. The second resonance tube includes a second opening surface from which the second sound is output. The second opening surface is displaced from the first opening surface in a normal direction K1.

An underwater sound source includes a cylindrical body having a front body portion, a rear body portion, a cylindrical piezo-ceramic ring transducer disposed therebetween, a flexible sleeve configured to cover an outer surface of the cylindrical piezo ceramic ring transducer, and a resonant pipe mounted to the cylindrical body and surrounding the cylindrical piezo-ceramic ring transducer. The resonant pipe is disposed around the cylindrical piezo-ceramic ring transducer, forming a gap between an inner surface of the resonant pipe and the outer surface of the cylindrical piezo-ceramic ring transducer.

An acoustic lens is presented that redirects high frequency voice sounds over a barrier to improve the intelligibility of speech when a protective barrier is used to isolate people from each other. The acoustic lens includes curved sheets to delay sound to create focal points on each side of a barrier, where the focal points are lower than the top of the barrier.

A device for manipulating an incident acoustic wave to generate an acoustic output is described wherein the device comprises a plurality of unit cells arranged into an array, at least some of said unit cells being configured to introduce time delays to an incident acoustic wave at the respective positions of the unit cells within the array of unit cells, such that said plurality of unit cells define an array of time delays to thereby define a spatial delay distribution for manipulating an incident acoustic wave to generate an acoustic output. The array of time delays may be re-configured to vary the spatial delay distribution of the device in order to generate different acoustic outputs. Also described are methods for designing or configuring such devices.

A sound output apparatus, a display apparatus and a method for controlling the same are provided. The sound output apparatus includes a housing; and at least one speaker provided on a side of the housing, wherein the housing includes an accommodation portion provided with an insertion groove to which the at least one speaker is inserted and mounted, wherein the at least one speaker includes a sound generator configured to generate a sound; and a guide tube that has a cross sectional area that changes from a first end of the guide tube to a second end of the guide tube, and wherein the guide tube receives the generated sound via the first end, and the guide tube includes an outer surface having a plurality of radiation apertures arranged in at least one row.

A sound output apparatus, a display apparatus and a method for controlling the same are provided. The sound output apparatus includes a housing; and at least one speaker provided on a side of the housing, wherein the housing includes an accommodation portion provided with an insertion groove to which the at least one speaker is inserted and mounted, wherein the at least one speaker includes a sound generator configured to generate a sound; and a guide tube that has a cross sectional area that changes from a first end of the guide tube to a second end of the guide tube, and wherein the guide tube receives the generated sound via the first end, and the guide tube includes an outer surface having a plurality of radiation apertures arranged in at least one row.

An acoustic meta material (AMM) spiral device for passive amplification of sound is described. The AMM amplifier device employs at least one deep sub-wavelength spiral design with high refraction index, based on an exponential spiral shape. The AMM spiral amplifier is used to focus on low frequency sound amplification and to cover broadband frequency range. Sound emanating from a speaker travels into a spiral channel until reaching the apex of the spiral. When twin spirals are used, the sound then enters a second spiral for radiating into open air.

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.