Showing papers in "Applied Acoustics in 1990"

TL;DR: A detailed account of the cross-correlation method involving the use of a periodic pseudorandom sequence for impulse-response and reverberation-decay measurements is presented.

TL;DR: In this paper, a panned wavetable synthesis method was proposed for high fidelity singing synthesis with vibrato waveform parameters and the role of spectrum modulation during the vibrato cycle was investigated.

TL;DR: In this paper, the authors investigated the relationship between the noise absorption coefficients of a cover made of woven fabric and its intrinsic parameters, including yarn count, cover factor, the air gap behind the fabric, the frequency of the impinging sound wave, and the influence of washing on the sound absorption capacity.

TL;DR: In this paper, the authors used the geometrical theory of diffraction to model simple and complex shaped noise barriers, such as thin walls, wedges, trapezoids with vertical or sloped walls and double thin walls.

TL;DR: It is shown that if many reflections are to be traced—in many practical cases more than two—the Sound Particle Simulation Method, with the same accuracy, represents a considerably more efficient and hence faster algorithm.

TL;DR: In this paper, a review of the recently published papers on the physics of the piano is presented, focusing mainly on the physical aspect of piano acoustics and those on the analysis/synthesis and evaluation of piano sound.

TL;DR: In this article, the surface of the barrier is divided into elements to solve the integral equations numerically and the potential is assumed to be uniform on each element; this reduces the amount of computation and avoids the difficulty due to singularity.

TL;DR: In this paper, a two-microphone sound-intensity technique has been used for the detection of defects in radially loaded ball bearings and the results show that the detectability of an outer-race defect is much better than that of an inner-race or ball defect.

TL;DR: In this paper, the authors describe the development of a multi-purpose facility which complies with current Canadian and American standards for the measurement of the real-ear attenuation of hearing protectors.

TL;DR: In this article, a modified off-the-shelf laser-doppler vibrometer (LDV) was used to measure vertical ground velocity for an impulsive atmospheric sound source for frequencies in the range 100-500 Hz.

TL;DR: In this article, the authors reported that the articulation index of 30 mosques in Amman, Jordan is between 0.39 and 0.59 where articulation score ranges between poor and fair.

TL;DR: In this article, room acoustical and architectural data from 32 concert halls have been subjected to statistical analyses in order to look for relationships between the position averaged acoustic data and various design variables.

TL;DR: In this paper, the AAS (Assisted Acoustics System), developed by the Yamaha group, is used in a detailed discussion on the validity of A-SF system with an FIR filter in the feedback loop.

TL;DR: In this article, a factorial, intra-muff study was performed to isolate the effects of earmuff-design alternatives with respect to clamping force/average pressure and earcup cushion filler.

TL;DR: The most common method of determining the performance of a system using statistical energy analysis is to solve a series of simultaneous equations as mentioned in this paper, however, there can be many advantages in deciding the performance on a path by path basis.

TL;DR: In this article, it was shown that the transmission loss of a triple partition may be much less than that of a double one of the same mass per unit area, which is in good agreement with laboratory measurements of transmission loss for double-spaced multiple glass units.

TL;DR: In this paper, the sound field propagated through an aperture of a room is calculated by means of an integral equation method, which requires both the velocity potential and its normal derivative on the aperture which are not known exactly.

TL;DR: In this article, a model of an existing factory was built at a scale factor of 1:16 and comparative measurements in the factory and its scale-model showed good agreement, with reverberation times generally correlated within 10% and the values for sound propagation with distance generally within 2 dB.

TL;DR: In this article, two kinds of psycho-acoustical experiments were conducted to investigate appropriate measures for assessing loudness of various noises in buildings, and it was found that the arithmetic mean value of sound pressure levels in octave bands is also a good measure for loudness estimation of low frequency noises.

TL;DR: In this article, it was shown that using only Maekawa's chart was not sufficient and that good correspondence was achieved between calculation results and the experimental data by taking the ground effect into consideration.

TL;DR: In this paper, Modal shapes and natural frequency coefficients for a significant range of the mechanical and geometric parameters that come into play were determined for an exact solution of the title problem, and the beam dynamic characteristics agreed with values already available in the open literature.

TL;DR: In this article, the basic mechanisms of sound generation in wind-excited musical instruments of the reed-woodwind, brass and flute families are outlined and a survey is given of the nonlinear effects that determine major features of sound production in these instruments.

TL;DR: In this paper, the maximum value of the residual shock spectrum, which indicates the frequency range over which a mallet is most effective, may vary with the strength of the blow, and experimental measurements show how this maximum frequency varies with blow strength for a number of mallets.

TL;DR: In this article, a method of scale model experiments for traffic noise prediction and design of traffic noise control facilities was developed, which may be useful to clarify complex factors, to verify theory and furthermore to formulate noise prediction.

TL;DR: In this article, it was shown that the string and bridge properties of a monochord violin can be explained by coupling between a string resonance and the bridge resonance, and the correlation between the two properties was analyzed.

TL;DR: In this paper, the effect of various roof constructions on noise transmitted to rooms beneath the roof and investigate the mechanisms of noise generation was investigated, and a simple prediction method was presented.

TL;DR: In this paper, the effects of a ridge on low-frequency acoustic propagation in quiescent and windy atmospheres were investigated using a parabolic approximation using an implicit finite-difference algorithm.

TL;DR: In this paper, a scale model has been made of the same concert hall in which the effects of some modifications of the ambient geometry were examined both from the objective standpoint and from the viewpoint of subjective acoustical quality.

TL;DR: In this article, the authors describe the acoustic design of an anechoic chamber built mainly for the measurement of the acoustic properties of electrical equipment and demonstrate that all the original acoustic design criteria had been reached, some even surpassed.

TL;DR: In this paper, the effects of harmonicity in the resonant frequencies of a brass wind instrument were investigated, and it was shown that a trumpet with optimum harmonicity maximizes this effect, producing an impulse response somewhat similar to that of a closed-closed tube.