Methods and systems for acoustically treating material are described. Acoustic energy is emitted into a waveguide having a wall with a shape that tapers away from the acoustic source. The wall may have a substantially conical or parabolic shape. When emitted therein, the waveguide causes convergence of the acoustic energy so as to form an acoustic focal zone at a vessel. In some embodiments, a substantial portion of the acoustic focal zone is located outside of the internal volume defined by the waveguide.

A device integrally joined with the ported opening of a musical bass drum resonant drumhead for regulating the amount of vibrating airflow passing through the inside of a bass drumshell and continuing through the ported opening for effectively controlling undesirable higher frequency drum sounds precipitated by the airflow produced upon the striking of the batter head.

A marine multibeam sonar device comprises a processing element and a transmitter. The processing element generates a plurality of transmit transducer electronic signals and inverts a polarity of a first portion of the transmit transducer electronic signals. The transmitter is in communication with the processing element and includes a plurality of transmit electronic circuits and a plurality of transmit transducers. Each transmit electronic circuit receives and processes one of the transmit transducer electronic signals, wherein a first portion of the circuits re-inverts the polarity of the first portion of the transmit transducer electronic signals. The transmit transducers receive the processed transmit transducer electronic signals from the transmit electronic circuits and generate a sonar beam.

Aspects are disclosed of a filler for occupying a volume. The filler includes an expandable filler positioned in the volume so that it occupies a percentage of the volume. The expandable filler can permanently expand from a first dimension to a second dimension upon the application of an expansion trigger. The filler also includes an acoustic filler made up of a plurality of acoustically active beads positioned with the expandable filler in the volume so that the acoustic filler can adsorb gas flowing into the volume. Other embodiments are disclosed and claimed.

A marine sonar display device comprises a display, a sonar element, a memory element, and a processing element. The display presents sonar images. The sonar element generates a sonar beam and presents transducer signals. The processing element is in communication with the display, the sonar element, and the memory element and receives the transducer signals, calculates sonar data from the transducer signals and generates a three-dimensional view of a portion of the body of water, wherein the view includes a plurality of sonar images. Each sonar image is generated from sonar data derived from a previously-generated sonar beam and includes representations of underwater objects and a water bed. The processing element also generates a cursor plane and a cursor positioned thereon, both of which appear on the three-dimensional view. The processing element further controls the display to present the three-dimensional view, the sonar images, the cursor plane, and the cursor.

Techniques are disclosed for systems and methods to provide networkable sonar systems for mobile structures. A networkable sonar system includes a transducer module and associated sonar electronics and optionally orientation and/or position sensors and/or other sensors disposed substantially within the housing of a sonar transducer assembly, which is coupled to one or more user interfaces and/or other sonar systems over an Ethernet connection. The sonar transducer assembly may be configured to support and protect the transducer module and the sonar electronics and sensors, to physically and/or adjustably couple to a mobile structure, and/or to provide a simplified interface to other systems coupled to the mobile structure. Resulting sonar data and/or imagery may be transmitted over the Ethernet connection and displayed to a user and/or used to adjust various operational systems of the mobile structure.

A sound insulation material 1 includes a first layer 10 constituted by a polyurethane foam, a second layer 20 that is laminated on a surface of the first layer, the surface being located on a first side, and that is constituted by a sheet-shaped member made from a material other than polyurethane, and a third layer 30 that is laminated on a surface of the second layer, the surface being located on the first side, that is constituted by a polyurethane foam, and that, over its entirety, has a higher density than the density of at least a portion of the first layer.

The present application described methods an apparatus for locating and/or monitoring subsea cables (101) having an optical fibre (105) deployed along its length. The optical fibre (105) is connected to a distributed acoustic sensing (DAS) interrogator unit to interrogate the optical fibre to provide a fibre optic DAS sensor. To locate the cable an acoustic stimulus is transmitted into the water from one or more known locations. The time of arrival of an acoustic signal matching the stimulus at the sensing portions of the DAS fibre can be detected and used to determine information about the location of those sensing portions to the known location. The DAS signals returns can also be monitored under ambient conditions to detect any signals indicative of likely damage to the cable.

A device and/or method for allowing authorization of computing device association using human-perceptible signals includes forming an association between a computing device and a further computing device. The computing device computes a fingerprint of a common key derived during the forming of the association and emits a first audio stimuli based upon the computed fingerprint. The first audio stimuli is at least one octave number apart from a second audio stimuli of the further computing device emitted by the further computing device based upon the common key.

An acoustic wave gate is provided. The gate includes one or more layers of metamaterial configured to be in a first state and a second state and configured to change from the first state to the second state when electrical and/or magnetic energy is applied thereto. The gate also includes at least one source configured in operational communication with the one or more layers and configured to supply at least one of electrical and magnetic energy to the one or more layers. The one or more layers are configured to (i) prevent the passage of acoustic energy through the one or more layers when in the first state and (ii) permit the passage of acoustic energy through the one or more layers when in the second state, wherein the one or more layers are configured to be stimulated in phase with the acoustic energy.