6 results about "Sound field" patented technology

The present invention relates to a single horizontal array passive speed measurement and distance measurement method based on sound field interference fringe, belonging to the field of underwater acoustic engineering and sonar signal processing. The method comprises a step of carrying out condition processing and collection on the signal received by each array element of a sonar, a step of carrying out beam formation on the collected signals and obtaining an azimuth time journey map after accumulation, a step of tracking an interested object, taking a tracking beam as object azimuth estimation, carrying out short-time Fourier transform spectrum analysis on the output of the tracking beam, obtaining the interference structural map of the interested object, selecting two equal time intervals of a single horizontal array in a motion process, forming interference structural maps, carrying out preprocessing and Radon transform on the two interference structural maps, and estimating an object heading angle with the combination of the waveguide invariant theory, and a step of realizing the estimation of the distance and speed of the interested object. According to the method, the physical nature of an underwater sound field is fully dug, the prior knowledge of a marine environment is not needed, the algorithm is simple and easy and is convenient and flexible to use, and the application prospect is wide.

A method for packing and/or mixing particulate materials, e.g., aerogel particles, includes combining materials having different particle sizes and applying a negative pressure differential in the presence of a sound field. A negative pressure differential in the presence of vibration also can be used. The method increases mixing and packing density.

[Problem] To provide a simple and economical device capable of providing an excellent sound field in accordance with the listener's preferences by adjusting the listener's interaural correlation coefficient. [Solution] A sound field adjustment filter (5) is provided with a pair of filter circuit groups (5L, 5R) corresponding to a left and right channel. This sound field adjustment filter divides a desired frequency band of the audio signal into multiple frequency bands and assigns prescribed transmission characteristics so as to generate a sound field adjustment signal for each frequency band such that a prescribed impulse response is configured cooperatively for the entire desired frequency band of the audio signal. The transmission characteristics adjust the audio signal for each split frequency band by the addition of time delay and gain. By means of operation output units (4L, 4R), the sound field adjustment filter (5) adds the sound field adjustment signals generated by each of the filter circuit groups (5L, 5R) to the audio signal of the other of the channels, and outputs the result to stereo speakers (2). The opening angle of virtual speakers with respect to the listener is changed by adjustment of the sound field adjustment signals so as to approximate the interaural correlation coefficient of a specific diffuse sound field.

The invention provides a mobile learning system large classroom with a non-electric sound amplifying function. According to the technical scheme of the mobile learning system large classroom with thenon-electric sound amplifying function, the problems that as for a mobile learning system large classroom, sound dispersing is uneven and poor in effect, consequently, the school teaching effect is poor, and interaction between teachers and students are unsmooth are solved. The mobile learning system large classroom mainly comprises wooden sound reflecting plates. Under the situations of taking full consideration of the sound absorbing effect and the reflecting effect, classroom steps, a platform, walls, a ceiling, seats, a floor and windows are integrally designed, thus harmony and unity of the sound pressure level, sound field uniformity and reverberation time of sound in the classroom are achieved, the effects which cannot be achieved through single design are achieved, and the new function that the sum of one, one and one is greater than three is achieved. After the test, when a teacher gives a lesson, the sound pressure level of students at the rear rows is increased, and the sound field uniformity of the front rows and the rear rows of the classroom are great; during questioning and answering of the students, the sound pressure level of the other students and the teacher arealso increased by about 25 decibels, the reverberation time in the classroom is in an expected value of about 0.83 second, and the auditory environment effect of the classroom is good.

A signal processing method and Automotive Audio System 290 comprising a tripolar loudspeaker configuration housed in at least one automotive head-rest assembly 200 or 500, whose radiation pattern, in conjunction with inter-element delays and other design features, is such that that passengers are afforded temporal and amplitude cues for achieving the desired soundfield appropriate for a variety of audio program material. Optionally, some or all of the headrest assembly transducers are aligned and configured with a Floating Waveguide member 470.