136results about How to "Reduce sound pressure" patented technology

A noise reduction apparatus includes: a speaker with a speaker unit held by holding means to make it possible to mix sounds emitted from front and rear of a vibration plate of the speaker; a microphone provided in an area where the sounds emitted from the front and rear of the vibration plate of the speaker are mixed and cancelled; and means for supplying a noise reduction audio signal obtained by phase-inverting an audio signal collected by the microphone to the speaker.

A microphone system has an output and at least a first transducer with a first dynamic range, a second transducer with a second dynamic range different than the first dynamic range, and coupling system to selectively couple the output of one of the first transducer or the second transducer to the system output, depending on the magnitude of the input sound signal, to produce a system with a dynamic range greater than the dynamic range of either individual transducer. A method of operating a microphone system includes detecting whether a transducer output crosses a threshold, and if so then selectively coupling another transducer's output to the system output. The threshold may change as a function of which transducer is coupled to the system output. The system and methods may also combine the outputs of more than one transducer in a weighted sum during transition from one transducer output to another, as a function of time or as a function of the amplitude of the incident audio signal. Methods of operating the system may include equalizing the outputs of two or more transducers prior to coupling one or more outputs to the system output.

An acoustic resonance device is installed in a compartment of a vehicle so as to reduce a low-frequency sound pressure (or noise) dependent upon a natural vibration. Specifically, an acoustic resonance device is a panel / diaphragm resonator, a resonance pipe, or a Helmholtz resonator, the inner space of which communicates with the compartment via an opening. The acoustic resonance device is positioned in proximity to an antinode of sound pressure owing to a natural vibration occurring in a driver / passenger space inside the compartment. Alternatively, the acoustic resonance device increases a particle velocity at a specific natural frequency or decreases sound pressure at an excitation frequency which occurs due to an external condition of the vehicle. The acoustic resonance device can be installed in a roof, a seat, a pillar supporting the roof, or a door of a vehicle.

In order to automate a microphone assembly process including a dust-proof treatment, an object of the present invention is to provide a dust-proof microphone having a configuration suitable for automated assembly. According to the present invention, a microphone has a plate-like or film-like dust-proof section that is disposed in a conductive housing (capsule) having a sound aperture and covers the sound aperture. The dust-proof section has a plurality of pores at least in a region corresponding to the sound aperture, and the dust-proof section further has a nonporous region. In the case of an electret condenser microphone, from the viewpoint of performance of the microphone, the dust-proof section is conductive. In addition, taking into account a soldering in a reflow furnace, the dust-proof section is heat-resistant. Each pore is desirably designed taking into account the environment for the usage of the microphone. However, if it is supposed that the microphone is used near one's mouth, each pore has an area of 0.01 mm2 or less. In addition, to enhance the dust-proof effect, the pores may be subjected to a water-repellent treatment.

A resonator is arranged in an intake system including a pipe section for partitioning an intake port from an intake passage that communicates the intake port with a combustion chamber of an engine, the resonator including: a branch pipe having one end branching to the pipe section and the other end closed so that a silencing chamber is defined therein; and at least one partition wall for partitioning the silencing chamber into at least one pneumatic spring chamber, the partition wall having a natural frequency lower than the frequency of silencing target sound of intake noise propagated from the intake passage.

An air intake sound control structure comprises a sound guiding pipe, a sound producing body, and a silencing means. The sound guiding pipe is branched off from a branch portion formed on a part of an air intake flow passage of an automobile, communicating with the air intake flow passage. The sound producing body is held by the sound guiding pipe at the position spaced apart from the branch portion, thereby sealing the sound guiding pipe, and producing a sound at a frequency which corresponds to its own natural vibration frequency by its vibration. The silencing means is disposed on the side of the branch portion of the sound guiding pipe and canceling a sound at a target frequency for suppression out of the air intake sound. The sound generated by the vibration of the sound producing body is transmitted into a vehicle interior.

A resonator 13 is provided including a resonating body 13 which is vibrated by intake air pulsation in an intake system 5, a volume chamber 14 connected through the resonating body 13 to the intake system 5, and a neck section 16 through which an interior space 15 of the volume chamber 14 is communicated with outside. The interior space 15 of the volume chamber 14 and interior of the intake system 5 are partitioned by the resonating body 13. The resonator is so set that a sound pressure in a certain frequency range is released from the neck section 16 to the outside under vibration of the resonating body 13. With this, the sound pressure characteristics of air intake sound can follow a rise in engine speed.

A noise reduction apparatus includes: a speaker with a speaker unit held by holding means to make it possible to mix sounds emitted from front and rear of a vibration plate of the speaker; a microphone provided in an area where the sounds emitted from the front and rear of the vibration plate of the speaker are mixed and cancelled; and means for supplying a noise reduction audio signal obtained by phase-inverting an audio signal collected by the microphone to the speaker.

Several embodiments of noise reduction apparatus for a fuel injector are disclosed and include perforated tubes, side branch filters and expansion chambers strategically located between a respective injector and the fuel rail to target and reduce high frequency noise generated by the mechanical movement of the fuel injector.

A pet abode with sound dampening characteristics comprising an interior space of a pet abode having sufficient dimensions to allow a pet to comfortably reside within the interior space. The interior space is formed from at least three walls where one or more of the walls exhibits sound dampening characteristics. The sound dampening characteristics reduces a one or more sounds originating from a source external to the interior space. That is, the interior space of the pet abode is sound proofed (or sound dampened), allowing a pet to be undisturbed by loud noises outside the interior space.

The ultrasonic sensor includes, on the same substrate, transmitter elements, receiver elements, a potential controller for receiver electrodes of the receiver elements, and a connection switching unit for the receiver electrodes and the potential controller. During the ultrasound transmission period of the transmitter elements, the connection switching unit connects the potential controller and the receiver electrodes. During the reception period of the receiver elements, the connection switching unit disconnects the potential controller and the receiver electrodes.

A loudspeaker unit (2) of a loudspeaker system (1) is fitted to a cabinet (4). An absorbent (3) is disposed in a hollow chamber (R) inside the cabinet (4) and absorbs a gas inside the hollow chamber (R). A phase inverting mechanism (8) inverts the phase by resonating with a sound of a specific frequency radiated from the loudspeaker unit (2) into the hollow chamber (R) and radiates this sound to outside. The watertight means of the phase inverting mechanism (8) prevents invasion of moisture into inside the hollow chamber (R) from outside the cabinet (4) through the phase inverting mechanism (8).

The present invention relates to a multiple channel earphone of small volume. In the earphone structure, a chamber tube with an adjusting hole or a set of adjusting holes is provided. The sound pressure of the chamber tube is naturally released without affected the performance of the main chamber sound field. When the external speaker connected to the chamber tube generates a large sound pressure, the sound pressure released naturally by the adjusting hole or a set of adjusting holes is increased accordingly, so that the sound pressure produced by the external speaker connected to the chamber tube is controlled by the main chamber.

The invention converts non audio systems into distributed audio sources for active noise control solutions. The system transforms non acoustic structures into soundboards using inertial type acoustic transducers. Acoustic parameters unique for each application due to the variation in properties of the sound board are compensated by equalizers. The invention also uses damping means to limit the reflection of bending waves from the edges. The inertial type acoustic transducer is driven by an amplifier. The acoustic signal to the amplifier is modified by a signal conditioner to compensate for the non optimal response of the acoustic system. An external controller communicates with the amplifier to control its operating parameters. A series of distributed audio sources in a variety of positions may each be addressable as a node on a network wherein noise detected at that source is analyzed and the system generates sound at that source to mask the noise.

A transformer for use in a power supply has a primary winding, a secondary winding, a bobbin on which the primary and secondary windings are separately wound, and a core subassembly mounted in the bobbin. An opening is formed in the cylindrical portion of the bobbin, and an inside core in the magnetic core insertion hole and an outside core located outside the hole are adhesively bonded together via a spacer through the opening in the cylindrical portion.

A monopole acoustic transmitter with at least one disc assembly with a plurality of piezoelectric discs configured to optimized acoustic pressure output within a desired frequency range while meeting physical restrictions of LWD and MWD logging systems. The transmitter is disposed in a recess or “slot” in the perimeter of a logging tool housing to reduce acoustic pressure waves transmitted directly along the tool housing and to optimize acoustic energy transmission into the borehole environs. In order to increase acoustic pressure output at a desired logging frequency range, the plurality of piezoelectric discs in each of at least one disc assembly are connected electrically in parallel and fired simultaneously. The polarity of the discs and the wiring arrangement are such that each disc expands or contracts in a common direction during simultaneous firing by an applied voltage. The desired output frequency is obtained by selectively polarizing and dimensioning the discs within the one or more disc assemblies. Each disc assembly is preferably disposed within an oil filled pressure housing that is pressure and temperature compensated. The axis of the at least one disc assembly can be parallel or perpendicular to the major axis of the logging tool.

A method for controlling a histotripsy using a confocal fundamental and harmonic superposition combined with hundred-microsecond ultrasound pulses, including: 1) positioning a target tissue by a monitoring and guiding system and adjusting a position of the target tissue to a focal point of a transducer; 2) first stage: controlling the confocal fundamental and harmonic superposition combined with hundred-microsecond ultrasound pulses to form a shock wave in a focal zone; wherein a negative acoustic pressure exceeds a cavitation threshold; an inertial cavitation occurs to generate boiling bubbles; the boiling bubbles collapse and achieve partial homogenization of the target tissue; 3) second stage: controlling the confocal fundamental and harmonic superposition combined with hundred-microsecond pulsed-ultrasound sequences to simultaneously irradiate a target zone and further mechanically disintegrate and homogenize the target tissue.

A centrifugal fan impeller structure includes a hub having multiple blades. The blades extend from a circumference of the hub in a direction away from the hub. Each two adjacent blades define therebetween a flow way, an air outlet and an air inlet. The air outlet and the air inlet are respectively positioned at two ends of the flow way in communication with the flow way. The air outlets are arranged at unequal intervals so as to greatly reduce noise in operation.

The invention relates to a gypsum heat preservation painting mortar construction process which comprises the steps that firstly, a base-layer wall is processed; secondly, according to the smoothness and perpendicularity of the surface of the base-layer wall, one wall is used as the datum, and a perpendicular square-setting elastic control line is hoisted; thirdly, gypsum bases are painted with mortar and used as angle beads; fourthly, the gypsum bases are painted with mortar and used as ash cakes and punching ribs; fifthly, gypsum heat preservation painting mortar is sprayed; sixthly, the gypsum heat preservation painting mortar is flattened and compacted, wherein the step of hanging nets on the junctions of different materials is further included between the second step and the third step; in the fourth step, after the ash cakes are manufactured and hardened, distribution cakes are manufactured and arranged through flax threads by controlling the ash cakes, so that the horizontal spacing between all the distribution cakes is not larger than 1500 mm; the steps of rib grinding and rib alignment are further included between the fourth step and the fifth step. Compared with the prior art, the gypsum heat preservation painting mortar construction process has the advantages that construction is convenient, plastering, scraping and repair are easy, the labor intensity is low, material consumption is lowered, the construction period is shortened, and construction cost is saved.

A method includes sensing sound pressure at a specified location, and a controller automatically adjusting a position of one or more fans among a plurality of fans to reduce the sound pressure sensed at the specified location. The position of the one or more fans may, for example, be adjusted using an actuator to change the distance from the fan and the specified location, which may be a location of a user. Optionally, the method may further include the controller automatically adjusting a speed of one or more fans among the plurality of fans to reduce the sound pressure sensed at the specified location. The position and speed of one or more fans may be adjusted to provide destructive interference at the specified location.

The present invention disclosed an all-digital speaker system device based on multi-bit Σ-Δ Modulation, comprising an A / D converter, an interpolation filter, a Σ-Δ modulator, a dynamic mismatch regulator, a differential buffer and a speaker array. The present invention takes advantage of the Σ-Δ modulation technique to effectively reduce the cost and complexity of the hardware realization of the speaker system device, thus realizing the full digitalization of the whole sound transmission link and the integration of the system device with low power dissipation and volume. Furthermore, the system device according to the present invention is provided with a better control ability on the local sound field, thus providing a better practicable method for the voice secret transmission.