Showing papers in "Applied Acoustics in 1979"

TL;DR: In this paper, a calculation model for sound transmission between dwellings by partitions and by flanking structures, based on the application of classical theory, is presented for the sound transmission among dwellings.

TL;DR: In this article, the effect of ambient noise on vocal output and the preferred listening level of conversational speech was investigated under conditions typical of everyday speech communication, and it was found that both speaker and listener try to compensate for the noise interference by raising the level of speech in order to keep the subjective loudness of speech (in noise equal to the loudness) in quiet.

TL;DR: In this paper, a modified Signal-to-Noise Ratio was derived from a best-fitting empirical correlation with speech intelligibility in a series of measurements in existing auditoria, and applied as design criteria to prediction and to evaluation techniques.

TL;DR: In this article, the particular problems of small-scale models, namely air absorption and transducers, are discussed and it is found that with a dehumidified atmosphere and currently available transducers the measurement of reverberation time, as well as impulsive type measurements such as early to late energy ratio and early decay time, is possible at a scale of 1:50.

TL;DR: In this article, the authors examined the action of a courtyard house in reducing the noise nuisance from road traffic using the techniques of computer simulation and acoustic scale modelling, and found that the most significant parameter was the height of the courtyard walls.

TL;DR: The design, performance and evaluation of hearing protectors are matters of substantial current interest as discussed by the authors, and specific scientific questions which command attention include the accuracy of the shift in free field hearing threshold as a measure of protection, the relationship between physical measurements of sound attenuation with real and artificial heads, the acoustical behaviour of hearing protector attenuation and speech intelligibility.

TL;DR: In this paper, the sound insulation of two sets of unsealed windows with different frame cross-sections was examined and the results showed that the unsealed steel windows had much lower sound insulations than unsealed timber windows for gaps of the same length and width.

TL;DR: In this article, measurements made on a system of two rooms separated by a wall but connected by a ventilation duct were used to determine the most important path from the source room, into the duct cavity, along the duct and then out into the receiving room.

TL;DR: The concept of sound character was introduced as a physical attribute responsible for any systematic differences in annoyance due to different sounds at the same A-weighted equivalent sound level as mentioned in this paper, and it is thought that this sound character is more important at low sound levels than at high ones.

TL;DR: In this paper, a three-dimensional ray tracing computer program was used to provide a picture of the sound energy distribution on the audience area of the hall, various room shapes being investigated.

TL;DR: The development of means of using a scale model of a road and its surrounding urban environment to predict L eq, L 10 and other measures of traffic noise is described.

TL;DR: In this article, it was suggested that the lower floors of high-rise buildings might be used for offices (or other noise-insensitive uses), while the upper, presumably quieter, floors could be used by housing, but this is not practical since, in many urban areas, the upper floors of buildings are exposed to almost as much noise as the floors near street level.

TL;DR: An empirical investigation of the errors in urban and transportation noise descriptors caused by the use of automatic monitoring sampling techniques is presented and should serve as a guide to potential and current uses of automatic monitors as well as indicating the probable accuracy of past studies.

TL;DR: In this paper, the authors proposed to use a power pink noise stabilised source with a range of 125 Hz-2 kHz in the source room, which generates a 90 dB(A) level in the receiving room, normalised to a source room absorption of A = 10 m 2.

TL;DR: In this article, a curve fitting method based on integration of the decay curve is applied to reduce the influence of flutter in order to measure the reverberation time without subjective interactions, both in the field and in the laboratory.

TL;DR: The cill and reveal of a panel or window are known to influence the Normalized Noise Reduction (NOR) process as mentioned in this paper, and additional observations upon their effect which may be employed to increase the sound insulation of rooms within the built environment.

TL;DR: In this paper, a simple method of ultrasonic fatigue testing is described which makes possible the design of similar samples of different materials, which have equivalent vibration characteristics and the same magnification factor.

TL;DR: In this article, the ability of tractor drivers to perceive tonal signals has been measured in a range of tractor and cab noise environments, including a simple open safety frame, a tractor with an experimental noise excluding cab, a noisy partially enclosed cab with a rigidly attached safety frame and sheet metal cladding and the latter condition with the driver wearing hearing defenders.

TL;DR: In this paper, the sound insulation provided by simple wood joist floors is known to be inadequate when such floors separate flats, and the effectiveness of various methods for improving sound insulation of this type of floor has been investigated.

TL;DR: In this article, a method for predicting the sound attenuation achieved by multiple barriers with knife edges and/or right-angled wedges is proposed, where the sound pressure level in the shadow region behind the multiple barriers can be obtained by successively setting imaginary sound sources for respective edges.

TL;DR: In this article, die Wirksamkeit veranderlicher Mesbedingungen und Masnahmen durch Vergleich mit der Ausgangssituation jeweils ablesbar ist.

TL;DR: In this paper, a simple method for measuring mechanical input power to a structure by direct analogue multiplication and integration of force and velocity signals is described, and the influence of phase errors is controlled through measurement of both the real and the imaginary power components.

TL;DR: In this article, an empirical investigation of the influence of standard deviation and skewness of traffic noise on the errors introduced into seven statistical noise descriptors by different digital sampling rates is reported.

TL;DR: In this paper, the applicability of correlation with acoustic noise and mechanical vibration signals is analyzed in terms of frequency bandwidth and length of record, and it is concluded that correlation is not as significant and useful a tool in the analysis of noise and vibration as might at first appear.

TL;DR: The bestimmung der Schalleistung nach dem Hullflachenverfahren is nur unter bestimmten Voraussetzungen anwendbar, die bei vielen industriellen Mesaufgaben vorhanden, bei anderen dagegen nicht gegeben sind as mentioned in this paper.

TL;DR: In this article, the title problem is solved assuming that the thickness varies symmetrically with respect to the x-axis, and the edges defined by x = ± a/2 are elastically restrained against rotation while the remaining edges are clamped or simply supported.

TL;DR: In this paper, a Schalleistungspegel bei Stosen an Platten is berechnet und aus den theoretischen Zusammenhangen larmmindernde Parameteranderungen abgeleitet.

TL;DR: In this paper, the authors investigate the attenuation of noise from single vehicles over short grass and show that for a microphone height of 1·2 m and a source/receiver distance 30 m, the rate of attenuation increases with distance.

TL;DR: In this paper, a system employing the radio frequency holographic method for the measurement of the reverberation time of an acoustic chamber is proposed, which has the advantage of supplying visible information on the diminishing intensity of the acoustic wave.