Topic
Sound power
About: Sound power is a research topic. Over the lifetime, 6337 publications have been published within this topic receiving 73363 citations. The topic is also known as: acoustic power.
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Patent•
28 Feb 1991
TL;DR: An arrangement for determining sound incidence values from sound emission levels of sound sources arranged in planes or similar contains a rule (1), hinged scale or measurement tape with a scale calibrated with the same graduations as the plane as mentioned in this paper.
Abstract: An arrangement for determining sound incidence values from sound emission levels of sound sources arranged in planes or similar contains a rule (1), hinged scale or measurement tape with a scale (3, 4) calibrated with the same graduations as the plane. The scale graduations are a measure of the sound level variaton with distance from the source. They corresp. to the difference between the source sound emission level and the incident point level. USE/ADVANTAGE - For simple, reliable mmeasurement by a lay person of sound incidence levels, e.g. at building windows or balconies, from defined emission levels of sources.
Patent•
28 Jul 2009
TL;DR: In this paper, the authors proposed a sound refining method that removes noise around a listener and provides an interfering sound at the same time, thereby reducing the noise that a listener is aware of.
Abstract: The present invention relates to a method and an apparatus for refining sound, especially to a sound refining method and apparatus which remove noise around a listener and provide an interfering sound at the same time, thereby efficiently reducing the noise that a listener is aware of. The sound refining method of the present invention comprises the steps of: receiving noise; generating an offset wave with the same intensity as, and an opposite phase to, the noise using an active noise cancelling unit; calculating the amplitude of the residual wave which is a composite wave of the noise and the offset wave; and generating an interfering sound of the amplitude to substantially remove the amplitude of the residual wave. The noise, offset wave, residual wave, and interfering sound substantially and simultaneously exist.
TL;DR: In this article, the authors describe the mechanism of sound generation on the piano, which is represented by an electrical circuit model, each string being represented by a transmis sionline, and the quantitative relationship of the model are calculated by a computer.
Abstract: The mechanism of sound generation on the piano can be divided into four stages:-(a) transmission of energy from a hammer to a set of strings, (b) propagation of energy in the strings, (c) transition of energy from the strings to the soundboard through the bridge, and (d) acoustic radiation of the energy from the soundboard. This process is represented by an electrical circuit model, each string being represented by a transmis sionline, and the quantitative relationship of the model are calculated by a computer. When a hammer strikes a string, a nearly half-sinusoidal pulse is generated, and this propagates along the transmission line, and then is reflected by the impedances of the bridge and the fixed end of the string. The propagation and reflection change the waveform of the initial pulse and reduce its amplitude. The driving velocity of the soundboard is produced by applying the sum of the forces of all the strings to the driving pointimpedance. This driving velocity produces a sound pressure, and its waveform is determined by the transmission characteristics of the soundboard. An artificial piano sound can be produced from a calculated waveform through a D-A converter. When the fundamental frequency of each string in a set is slightly detuned, they produce beats in each partial making an inharmonic sound. The lower partials in the produced sound change relatively slowly, while the higher partials change relatively rapidly. The amplitude of the initial part of the sound ('initial sound') decays rapidly, while that of the sustained part ('aftersound') decays slowly. This explains how a delicate timbre of the piano sound is produced.
TL;DR: In this paper, the results of the simulated transmission loss are presented and compared with common analytical prediction methods based on the transfer matrix method, which can be used to obtain good quality simulations.
Abstract: The most important characteristic in building acoustics is the transmission loss which describes the insulation performance of a separating component. This quantity is defined by the ratio of inclined sound power to transmitted power. The transmission loss is usually measured in costly experimental set-ups of either real size facilities or down scaled test models. In order to reduce the effort and to gain further insight into the complex behavior of wave propagation in coupled structure-fluid systems, virtual test facilities using numerical methods (FEM) are established. An appropriate determination of the reverberation time is essential for obtaining good quality simulations. The results of the simulated transmission loss are presented and compared with common analytical prediction methods based on the transfer matrix method. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)
Patent•
19 Dec 2017
TL;DR: In this article, an acoustic testing bench for sound absorbers contains the metal case with the removable front lid, the walls of which are lined with the tested sound absorber, differs in that the adjustable noise source is set on the body bottom through the elastic damping gasket, besides, the adjustment is carried out according the sound volume and signal frequency, using the signal power amplifier and oscillograph, and at the distance of 1 m from the housing cover the microphone is fixed, the sound pressure levels signals from which go to the frequency spectrum analyzer, and then to the
Abstract: FIELD: testing equipment.SUBSTANCE: acoustic testing bench for sound absorbers contains the metal case with the removable front lid, the walls of which are lined with the tested sound absorber, differs in that the adjustable noise source is set on the body bottom through the elastic damping gasket, besides, the adjustment is carried out according the sound volume and signal frequency, using the signal power amplifier and oscillograph, and at the distance of 1 m from the housing cover the microphone is fixed, the sound pressure levels signals from which go to the frequency spectrum analyzer, and then to the computer to process the information received, at that the sound power level Lis determined by the measurements results of the average sound pressure level Lat the measuring surface S, m, which is taken as the hemisphere area:, where S=2πr; r - the distance from the source center to the measurement points; S=1 mand the corrected sound power level L:, where L-average sound level at the measuring surface and value of the sound pressure level ΔL reduction in the sample reflected sound field the is calculated by the formulawhere L-sound pressure level at the calculating point up to acoustic treatment of the room, dB; L-sound pressure level at the calculating point after the acoustic treatment of the room, dB, B- constant of the vessel cabin before its acoustic treatment, m; B- constant of the room after its acoustic treatment, m, which is determined by the formula wherewhere A=α(S-S) - the equivalent area of sound absorption by surfaces, not occupied by the sound-absorbing lining;α= (B)/(B+S) - average sound absorption coefficient in the room before it is acoustical treatment; α-average sound absorption coefficient of acoustic treated room, defined by the ratio, where ΔA - the value of total optional absorption, made by the design of the sound absorbing lining or single piece sound absorbers, determined by the formula ΔA=αS+An, where α- reverberation sound absorption coefficient of lining design; S- area of this design, m; A- the equivalent sound absorption area of single piece absorber, m; n is the number of single piece absorbers in the room, differs in, that for testing the effectiveness of acoustic ceiling coated with sound absorber, remove the absorber from the metal body walls and the effective part of adjustable noise source direct to the ceiling part of the body and turn it on by subsequently changing the sound volume and the signal frequency, then send the signals from the microphone to the power amplifier, such as strain gauge, and send the signals from it to the oscillograph and record the oscillograms of the sound pressure levels, according to which determine the efficiency of acoustic ceiling.EFFECT: expanded technological capabilities of objects testing, having several elastic couplings with the body parts.3 dwg