34results about How to "Reduce loudness" patented technology

A drum damper for a musical drum comprises a first portion including material having high impact strength and durability suitable for withstanding the forces generated by striking a musical drum. A second portion includes material having sound damping properties suitable for reducing the sound level generated by striking a musical drum.

The present idea refers to an apparatus for generating an adapted audio file. The apparatus comprises an identification unit (51) for supporting identification of a frequency range (fr) associated with an auditory disorder of a user of the apparatus, and an adaptation unit (52) for adapting a frequency characteristic of an audio file (af) representing a track of music which adaptation is subject to the identified frequency range (fr). An audio player (6) is provided for playing the adapted audio file (aaf).

The invention provides a multichannel sound mixing method and apparatus. The method comprises the following steps: obtaining multiple paths of channel signals used for transmitting a current frame; performing volume expansion summation on the multiple paths of channel signals to obtain a sum signal of the current frame; obtaining to-be-analyzed frame data; limiting the amplitude of the to-be-analyzed frame data in an amplitude limiting manner to obtain a sampling value after amplitude limiting; and outputting the data of N sampling points in front of the sampling value after amplitude limiting to obtain a target audio signal. In the multichannel sound mixing method provided by the invention, the sound mixing is performed by combining the volume expansion summation with the amplitude limiting, so that the sound quality of the obtained target audio signal is better and is more real, and the technical problem of serious distortion of sound mixing in the traditional sound mixing method is relieved.

The invention discloses an exhaust resonant silencer and a motorcycle with the same. The exhaust resonant silencer comprises a silencer barrel and an internal tube assembly arranged in the silencer barrel for introducing and exhausting waste gas; the internal tube assembly includes a front tube, a middle tube and a tail tube, the tail tube is communicated with the middle tube for introducing waste gas into the tail tube, part of the tail tube is sleeved with a sleeve, a first resonant cavity is formed between the sleeve and the tail tube, and the sidewall of the tail tube corresponding to the sleeve is provided with a radial resonant hole whereby an inner cavity of the tail tube is communicated with the first resonant cavity; the resonant cavity is arranged in the silencer, so that loudness and sharpness of high-frequency noise can be decreased; the tone is greatly improved; through simple adjustments on internal structure of the silencer, the cost of the silencer can be effectively reduced without decreasing the silencing performance of the silencer or affecting dynamic performance of an engine.

The invention discloses an electric hair drier, and belongs to the field of household appliances. The electric hair drier comprises an electric hair drier body and a handle, wherein the two ends of the electric hair drier body are provided with an air inlet and an air outlet respectively, the air inlet and the air outlet are provided with sound quality regulating devices respectively, and each sound quality regulating device comprises a shell body matched with the shape of the electric hair drier body and a sound production assembly arranged in the corresponding shell body; the two ends of each shell body are provided with sealing plates, the inner portion of each shell body is provided with a spiral airflow channel in the axial direction of the shell body, each sound production assembly comprises a microcontroller comprising a storage module and a micro speaker arranged in an outlet of the corresponding spiral airflow channel, and sound files are pre-stored in the storage modules. Combined with the noise elimination design of the spiral airflow channels, the loudness of the noise of the electric hair drier is reduced, according to the used air volume gear of the electric hair drier, the preset sound files are played automatically through the sound production assemblies, the time-frequency characteristics of the noise of the electric hair drier are regulated, the sound comfortlevel is improved, and the sound quality of the electric hair drier is improved.

The invention relates to a method for operating an asynchronous machine comprising the steps: determining an operating point trajectory for the asynchronous machine for a plurality of desired torques of the asynchronous machine by calculating 2-tuples from longitudinal current values and cross current values in a synchronously rotating coordinate system of the asynchronous machine; calculating a slip frequency of the asynchronous machine for each of the 2-tuples calculated from longitudinal current values and cross current values; determining a current rotor speed of the asynchronous machine; calculating an excitation frequency of the asynchronous machine by summation of the calculated slip frequency and the current rotor speed weighted with the number of pole pairs of the asynchronous machine; and comparing the calculated excitation frequency of the asynchronous machine with at least one predetermined resonance frequency value of the asynchronous machine. The determined operating point trajectory is thereby corrected by changing the ratio between longitudinal current value and cross current value at a constant desired torque for each of the 2-tuples for which the calculated excitation frequency corresponds to the at least one resonance frequency value.