Showing papers in "Applied Acoustics in 1976"

TL;DR: In this paper, the difference between tapping and walking noise spectra has been established by measurements on 49 different floors and a new set of reference values has been derived, based on the assumption that the NR-curves provide a correct subjective rating system for walking noise.

TL;DR: In this article, a preliminary survey on annoyance by traffic noise in big cities was carried out in order to prepare a large-scale research program on annoyance of traffic in big Belgian cities.

TL;DR: A computer program, based on the OCMA Specification, is helpful in this work and helps to identify the possible methods of noise reduction and to select the best by cost/benefit analysis.

TL;DR: Improved analogies for system elements are derived, thus arriving finally at a complete electrical analogy of a compound mounting system for resilient mounting systems in buildings.

TL;DR: In this paper, a direct acceleration method for measuring the sound power being radiated by individual room surfaces is described, and an account is given of the successful testing of the method on lightweight panels radiating into an anechoic chamber.

TL;DR: In this article, the authors describe the experience of the oil industry in specifying noise limits for new plants using the procedure published by the Oil Companies Materials Association, which defines a calculation method for predicting the noise in neighbouring areas due to a plant, including curves for deriving the excess attenuation due to ground effects.

TL;DR: In this paper, a combination of existing theories for predicting the distribution of sound intensity in rooms and the performance of acoustical barriers are applied in designing a barrier to reduce noise in an industrial environment.

TL;DR: In this paper, sources of noise present in swirl burners in the non-combustive and combustive cases are experimentally investigated and the main source of noise is the precessing vortex core, a three-dimensional time-dependent instability present in such burners at high degrees of swirl.

TL;DR: In this paper, a one-fourth scale model of the National Bureau of Standards (NBS) reverberation room is described, and the effect of increased low frequency absorption upon room qualification is tested in the model room.

TL;DR: In this paper, the authors describe the design, construction and performance evaluation of a small test facility for transmission loss measurement, which is made of laminates of masonite, fibreglass, and plywood.

TL;DR: In this paper, the A-weighted sound level difference between the linear sound level of a source of white noise and the A weighted received level was measured using a sound level meter.

TL;DR: In this article, the performance of typical three-sided noise enclosures was predicted using diffraction theory and the agreement with measured results was reasonably good and thus the technique developed is of practical value.

TL;DR: In this paper, the authors present the results of some experiments on the use of structures of aerodynamically-shaped elements as narrow-band sound reflectors in a duct, tuned to give maximum attenuation for frequencies determined by the Bragg reflection condition.

TL;DR: The laboratory test chamber described in this paper was designed to provide a test facility for the measurement of airborne sound insulation of party walls and their associated flanking construction as mentioned in this paper, which was developed as a research tool to overcome the need to carry out field measurements on new dwelling types, the results obtained in the chamber were found to be in close agreement with the results of field measurements in dwellings with similar constructional detailing.

TL;DR: In this paper, the authors examined the use of various statistical parameters for assessing the noise due to the plant and described a method of minimising the effect of extraneous noises due to traffic, and emphasized the need to agree on a single parameter which can be used for calculations, for assessing measured noise levels, and for comparison with legal or noise criteria, and recommends the general adoption of L eq.

TL;DR: In this article, the authors investigate the nature and level of sound emitted in rooms served by air-conditioning systems and find that the sound pressure level in the room could be predicted by the equation: L =40 v 17 + 1 or: L=374 N 2110 + 1 where L is the soundpressure level in dB(A), v is the air velocity in the main duct and N is the fan speed (rpm).

TL;DR: In this article, the authors explored the response of six machine tools in a workshop when operating individually (solo) and together (simultaneously) and made a comparison between the resulting power spectral density spectra when all machines were working together and the computer-summated spectra of the machines when running individually.

TL;DR: In this article, the theoretical and experimental disposition and feeding of the sources in an array with the aim of obtaining a cardioid directivity pattern in a wide frequency range is described.

TL;DR: In this paper, the authors describe measurements made in conditions of high absorption, with a single directional source, and compare these measurements with the predicted transmission loss from a capacitive transducer and the effect of sealing the panels.

TL;DR: In this article, a negative correlation swischen dem Raumeindrucksmas R and dem Klarheitsmas C is defined, e.g., r CR = −0,77.

TL;DR: In this article, the unterschiedlichen Maximalpegel der einzelnen Fahrzeuge bei der Vorbeifahrt and die zeitlichen Abstande der FHVs zueinander (Folgezeiten) were investigated.

TL;DR: In this article, the authors report on the findings of a survey that investigated buildings for acoustic intrusions from the services and find that fifty per cent of the buildings looked at had failures and thirty per cent serious faults.