A sound bypass device configured to transmit engine-generated sound pulses from an engine to a sound outlet whilst preventing flow of gases to the sound outlet, the sound bypass device comprising: an input tube configured to conduct the engine-generated sound pulses from the engine; and a sound transmission device connected to the input tube at a first end and to the sound outlet at a second end, the sound transmission device comprising: a first volume connected to the first end, a second volume connected to the second end, and a flexible diaphragm separating the first volume from the second volume and configured to transfer variations in pressure in the first volume to the second volume; wherein the first volume has a cross-sectional area that is greater at the diaphragm than at the first end and the second volume has a cross-sectional area that is greater at the diaphragm than at the second end.

A variable acoustic assembly comprising a housing and a one or more absorbing pads. The housing contains the one or more absorbing pads, a one or more doors, a one or more rear brackets, and a one or more hinges. The one or more doors attach to the one or more rear brackets with the one or more hinges. The one or more doors are configured to selectively open and selectively close between an open configuration and a closed configuration by rotating on the one or more hinges. The variable acoustic assembly having a closed width in the closed configuration and an open width in the open configuration. With the one or more doors in the open configuration, a portion of the one or more absorbing pads are exposed outside of the housing.

Methods, systems, devices, and products for ultrasonic borehole logging using an ultrasonic borehole imaging tool in a borehole intersecting the earth formation. Methods may include adjusting a focus for an ultrasonic beam generated from a single-transducer ultrasonic assembly of the ultrasonic imaging tool; using a receiver to generate measurement information responsive to an ultrasonic signal caused by the ultrasonic beam; and estimating a parameter of interest from the measurement information. Methods may include adjusting the focus in dependence upon environmental conditions, the environmental conditions comprising at least one of: i) standoff between the ultrasonic imaging tool and a wall of the borehole; and ii) borehole annulus conditions. Methods may include adjusting the focus in substantially real-time. The ultrasonic beam may be focused with a focal zone at the borehole wall configured to produce a beam spot size of a selected diameter.

A sound amplification structure includes a sound path that is formed by an underfloor foundation of a building and a concrete peripheral wall formed by standing up approximately vertically from the underfloor foundation. One end of the sound path (a speaker unit communication section) is able to communicate with a floor speaker unit placed in a room of the building. A width of the sound path widens from the one end toward other end of the sound path. The other end of the sound path (an output unit) is able to output sounds that are emitted from the floor speaker unit and amplified through the sound path. A length of the sound path is 4 m or longer. Preferably, the sound path is U-shaped, Z-shaped, or a zig-zag shaped. The concrete peripheral wall preferably doubles as a building foundation structure.

A sound amplification structure includes a sound path that is formed by an underfloor foundation of a building and a concrete peripheral wall formed by standing up approximately vertically from the underfloor foundation. One end of the sound path (a speaker unit communication section) is able to communicate with a floor speaker unit placed in a room of the building. A width of the sound path widens from the one end toward other end of the sound path. The other end of the sound path (an output unit) is able to output sounds that are emitted from the floor speaker unit and amplified through the sound path. A length of the sound path is 4 m or longer. Preferably, the sound path is U-shaped, Z-shaped, or a zig-zag shaped. The concrete peripheral wall preferably doubles as a building foundation structure.

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.

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.

A bone conduction speaker includes a housing, a vibration board and a transducer. The transducer is located in the housing, and the vibration board is configured to contact with skin and pass vibration. At least one sound guiding hole is set on at least one portion of the housing to guide sound wave inside the housing to the outside of the housing. The guided sound wave interfaces with the leaked sound wave, and the interfacing reduces a sound pressure level of at least a portion of the leaked sound wave. A frequency of the at least a portion of the leaked sound wave is lower than 4000 Hz.

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.

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.