10 results about "Mid-frequency" patented technology

This invention provides a multi-layered lightweight sound-absorbing and insulating material, comprising a layer of sound-absorbing cotton, a cup-shaped plastic film layer, and a plastic board layer stacked together. Multiple cup-shaped structures are arranged in an array on the cup-shaped plastic film layer. Each cup-shaped structure has a second through-hole at its bottom, and these structures are arranged periodically according to the size of the second through-hole. Within each arrangement cycle, there are multiple second through-holes with different diameters. The cup-shaped structures corresponding to the different diameters of the second through-holes form multiple Helmholtz resonators with different resonance frequencies. This invention forms multiple Helmholtz resonators with different resonance frequencies through multiple cup-shaped structures with different through-hole diameters. The coupling effect of the perforated cup-shaped structures with different resonance frequencies generates a continuous and wide mid-to-low frequency resonant sound-absorbing band. While possessing a certain high-frequency sound absorption capability, it significantly improves the low-to-mid frequency sound absorption and insulation capability. Compared with traditional porous sound-absorbing materials such as felt fibers and sound-absorbing cotton, it greatly improves the sound absorption and insulation capability at the same thickness.

Provided herein are high-fidelity, free-standing, wireless, glass speaker systems with a curved glass that is wide at the base and narrow on top, the width being gradually reduced all the way to the top, and having three slots at the top to reduce the mass of the glass. The shape of the glass is configured to create a dynamic range of sound, to allow low frequencies to resonate more prominently at the bottom, and high frequencies to be more prominent at the top of the glass, and the mid frequencies to resonate more prominently in the middle section of the glass.

To provide a composite molded body that can be suitably used as a ventilation adjustment layer that has excellent sound absorption properties in the low to mid frequency bands and also has excellent three-dimensional shaping properties.SOLUTION: According to the present disclosure, there is provided a composite molded body containing fibrillated fibers and short fibers. The composite molded body has an areal density of 30 g / m2 to 1000 g / m2 and an air permeation resistance per unit thickness of 15.0 s / (100 mL.mm) or less. According to the present disclosure, there is also provided a composite sound-absorbing material having a thickness of 10 mm or less, in which a ventilation adjustment layer and a porous material are laminated. In one embodiment, the ventilation adjustment layer has specific sound absorption characteristics in accordance with JIS A 1405. In another embodiment, the ventilation adjustment layer has a total areal density of 100 g / m2 to 1000 g / m2, a total air permeation resistance of 0.1 s / 100 mL to 2.0 s / 100 mL, and a total thickness of 0.50 mm to 5.00 mm, and the thickness of the porous material is 5.00 mm or more.SELECTED DRAWING: Figure 1

A circuit tuning radio frequency (RF) power. The circuit includes a low to mid frequency (LF / HF) tuning circuit including a variable LF / MF capacitor coupled in series with an LF / MF inductor. The LF / MF tuning circuit is coupled between ground and a common node configured to receive an RF input. The circuit includes a high frequency (HF) tuning circuit coupled in parallel to the LF / MF tuning circuit between ground and the common node. The HF tuning circuit includes a variable HF capacitor coupled in series with an HF inductor. Cross parallel isolation occurs between the LF / MF inductor of the LF / MF tuning circuit and the HF inductor of the HF tuning circuit when adjusting the variable LF / MF capacitor or variable HF capacitor.

Acoustic output device, comprehensive: a bone conduction loudspeaker configured to generate bone conduction sound waves; an air conduction loudspeaker comprising a diaphragm, wherein the air conduction loudspeaker is configured to generate air conduction sound waves by vibrating the diaphragm, where the air conduction loudspeaker is independent of the bone conduction loudspeaker; at least one enclosure configured to house the bone conduction loudspeaker and the air conduction loudspeaker; where the angle between the direction of vibration of the bone conduction loudspeaker and the direction of vibration of the center of the diaphragm of the air conduction loudspeaker is 70° to 115°, Bone conduction sound waves have medium to high frequencies, while air conduction sound waves have low to medium frequencies.

A speaker system mounted in a vehicle has a low frequency speaker and a mid frequency speaker disposed above the low frequency speaker in a vertical axis, which reduces the case where the position of the sound image of the mid frequency sound is shifted downward. A speaker system (1A) has a low frequency speaker (WF), a mid frequency speaker (SC), a filter (111), and a filter (112). The low frequency speaker (WF) and the mid frequency speaker (SC) are disposed in front doors of a vehicle. The mid frequency speaker (SC) is disposed at a position above the low frequency speaker (WF) in a vertical axis in a vertical direction. The filter (111) is a low pass filter disposed between an output terminal (20) of an amplifying device (2) and the low frequency speaker (WF). The filter (112) is a high pass filter disposed between the output terminal (20) and the mid frequency speaker (SC). A cross-over frequency between a frequency response of an output system (L1) including the filter (111) and the low frequency speaker (WF) and a frequency response of an output system (L2) including the filter (112) and the mid frequency speaker (SC) is 300 Hz or less.

To provide a sound barrier that reduces manufacturing effort and offers excellent sound insulation performance in a low-to-mid frequency range.SOLUTION: A sound barrier 1 comprises a sound-insulating structure 2 and a facing material 3. The sound-insulating structure 2 includes a plate material 10, a plurality of core materials 20 arranged adjacent to each other, and a frame material 30. The core materials 20 consist of cylindrically formed rectangular thin plates, one axial end of the core material 20 is bonded to a sound-insulating surface 11 of the plate material 10. Adjacent core materials 20 are capable of sliding against each other at their side wall portions. The facing material 3 is oppositely disposed relative to the sound-insulating structure 2 via an air layer 5 at the axial other end of the core material 20. Since the adjacent core materials are not bonded together and can slide relative to each other, influence of vibration from one core material on its neighbor core material is small, allowing each core material to efficiently dampen vibration. Furthermore, because the facing material is disposed opposite relative to the sound-insulating structure via an air layer, the sound barrier exhibits excellent sound insulation performance in a low-to-mid-frequency range.SELECTED DRAWING: Figure 4

An audio signal processing method for removing near-field voice, according to one embodiment of the present disclosure, may comprise a step of acquiring an input audio signal (10). The method may comprise the steps of: splitting the input audio signal (10) into a low frequency band signal (222), a mid frequency band signal (224), and a high frequency band signal (226); determining, on the basis of the low frequency band signal (222), whether near-field voice is included in the input audio signal (10); extracting a far-field component (232) from the low frequency band signal (222) if near-field voice is included in the input audio signal (10); and generating an output audio signal (20) by using the far-field component (232) extracted from the low frequency band signal (222), the mid frequency band signal (224) and the high frequency band signal (226).

This invention discloses a mid-to-low frequency hybrid broadband sound absorber, comprising: a first Helmholtz resonator with a first absorption peak frequency band; a second Helmholtz resonator with a second absorption peak frequency band; the second absorption peak frequency band being higher than the first absorption peak frequency band; and a plurality of discrete porous material blocks; the first and second Helmholtz resonators are spatially separated by at least one of the plurality of porous material blocks. This invention achieves effective extension of low-frequency sound absorption to mid-frequency; it achieves effective connection and fusion of optimized mid-to-high frequency sound absorption bands with extended low-to-mid frequency sound absorption bands; the sound absorber of this invention forms continuous, flat, and efficient broadband sound absorption performance within the target frequency band. Simulation verification shows that the average sound absorption coefficient in the 400Hz-2000Hz frequency band can exceed 0.8.

Apparatus includes a filter, band filter circuitry, and a controller. The controller is coupled to the filter and the band filter circuitry. The filter attenuates a portion of an audio signal based on a cutoff frequency. The band filter circuitry separates the audio signal into a low frequency band, a mid frequency band, and a high frequency band. The controller adjusts the cutoff frequency of the filter based on a ratio of energies for two of the frequency bands of the audio signal and based on a model of a human perception of audio.