摘要:

A single number index, called the exterior wall rating, or EWR, has been developed for rating the sound transmission loss of A‐weighted sound levels for exterior facades. This index is closely patterned after, but distinctly different from, the STC single number index. The latter provides a reliable rating for the sound transmission loss of interior partitions for typical interior sounds, but is not suitable for assessing the sound transmission loss of exterior walls to major sources of outdoor noise. However, by applying principles similar to those upon which the STC rating was developed, a practical index was constructed which can reliably rate exterior walls in terms of their ability to attenuate A‐weighted sound levels. EWR originally evolved out of a systematic analysis of 1/3‐octave‐band sound transmission loss data for over 225 wall constructions and 33 different window constructions with four different relative areas from 0%–20% of the wall areas. From this analysis of over 22 500 combinations of structural assemblies, EWR was found to be a substantially more accurate predictor of attenuation of A‐weighted sound levels than other candidate indices. These included a modified STC, SIL, and average TL values for 16 1/3‐octave bands. EWR includes a necessary correction for the different spectra of aircraft and highway noise, and thus provides an efficient method for the design or analysis of sound insulation treatment of buildings to attenuate noise from these major outdoor noise sources. One such application is considered in paper HH4 by David Brown [J. Acoust. Soc. Am. Suppl. 180, S67 (1986)]. The basic methods for calculating EWR values from standard TL data are defined to encourage sound‐transmission‐loss‐testing‐laboratory operators and users to apply this practical method for rating sound transmission loss of exterior walls.

ISSN:0001-4966    

DOI:10.1121/1.2024001

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

A mathematical theory was developed for sound transmission through single glazed windows assuming a line sound source and the appropriate angles between the location of the window in the building and the source. The predicted internal sound pressure levels using the theory and sound transmission loss values from ASTM E90 are compared to measurements in several buildings.

ISSN:0001-4966    

DOI:10.1121/1.2024005

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

Published residue pitch measurements give the pitch of the missing fundamental for tones consisting of three, and even two, successive harmonics over a wide range of harmonic numbers and frequencies. Presentations closer to a musical context give other results. Scales spanning an octave played with two and three sinusoidal components of constant frequency difference sound like steadily ascending scales. The last tone (frequency ratio 3:2 or 4:3:2) sounds higher in pitch than the first (frequency ratio 2:1 or 3:2:1) when played immediately after it. Other examples contrast the first 6 equal‐amplitude harmonic partials with tones consisting of the upper 2, 3, 4, and 5 harmonics. These latter tones do not match the pitch of the 6‐partial tone when the literature says they should. Tunes and scales were played with tones with two sinusoidal components spaced by the pitch frequency. The tune or scale is heard only at high levels, and “in the ear,” not coming from the speakers. Can there be pitch without place? Reported residue pitches do not correspond to pitches heard in a musical context.

ISSN:0001-4966    

DOI:10.1121/1.2024010

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

Subjects were presented with two musical chords in succession, called the prime and target, respectively. The prime and target were either related (e.g., C and D major, respectively, sharing a parent key) or unrelated (e.g., C and F♯ major, respectively, sharing no parent key). Subjects judged, as quickly as possible, whether the target was in tune or out of tune. Response times for in‐tune targets were faster when prime and target were related than when they were unrelated, suggesting that the prime generated expectancies for related targets. Priming occurred even when prime and target shared no partials. These results suggest that chordal expectancies generated by a musical context are not due solely to priming at the level of individual frequencies, but also involve priming at a more abstract level of chord function, implicating a cognitive representation of chord relationships. A network model of chord relationships is proposed whereby chord nodes activate related chord nodes via links to their parent key nodes.

ISSN:0001-4966    

DOI:10.1121/1.2024011

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

A unique series of tests with the Seattle Orchestra in the calibrated Seattle Auditorium was staged to experiment with section arrangement within the orchestra enclosure. New values for relative and absolute power output from instruments and sections as a function of dynamic playing level were derived. Results demonstrate that relative placement and elevation of sections can be used to greatly improve intersection balance and choral effects. A unique and strange stage arrangement emerges.

ISSN:0001-4966    

DOI:10.1121/1.2024020

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

The inverse problem in the propagation of sound through inhomogeneous fluids, that is, determining quantitative parameters characterizing the inhomogeneity fields from the changes in acoustic waves propagating through them, forms the basis for acoustic remote sensing. After a brief review of the development of remote sensing methods, recent advances—and problems—will be discussed, including measurement of velocity fields, and profiles of temperatures versus altitudes or depths. The possibilities of obtaining phase information and much larger scattering cross sections from fields of Rayleigh scatterers when their spatial correlations do not vanish (a topic under way in studies of radar sensing of clouds) may present opportunities for improved acoustic remote sensing.

ISSN:0001-4966    

DOI:10.1121/1.2024024

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

Waves propagating in real media such as the atmosphere, ocean, earth, seafloor sediments, etc., are subject to attenuation due to both intrinsic absorption and scattering by medium inhomogeneities. Measurements of attenuation in such media yield the combined effect of these two mechanisms but do not yield directly the individual effect of each of them acting in isolation. In order to obtain information on these individual attenuation mechanisms from measurements of the total attenuation, it is necessary to use analytical techniques based on the theory of wave propagation in the medium. The purpose of the present investigation is to derive such a technique for the case of scalar waves propagating in a one‐dimensional, weakly dissipative, randomly inhomogeneous medium. The approach makes use of analytical expressions derived previously for the mean intensity and mean squared intensity of the field. With the aid of measurements of these two quantities, both the absorption coefficient and the scattering coefficient (of attenuation) of the medium can be obtained. [Research supported by NORDA.]

ISSN:0001-4966    

DOI:10.1121/1.2024035

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

In order to examine the effect of tone location on temporal order discriminations, tones (200‐ms onset‐onset) in six‐tone sequences were either presented all in one spatial location or were alternated between two spatial locations. On each trial a comparison sequence differed from the standard sequence, either such that the tones in each spatial location contained an order change or such that, when the tones were alternated between locations, only one spatial location contained an order change. In a 3IFC task, subjects chose the sequence in which the component tones were in a different order. Discrimination performance remained above chance in all conditions; however, performance was significantly worse when the tones alternated between locations and only one location contained an order change. These results support the hypothesis that temporal relationships between tones presented in the same spatial location are more salient than relationships between tones presented in different locations; they also support the assertion of Warren and Byrnes [Percept. Psychophys.18, 273–280 (1975)] that subjects can discriminate the order of perceptually unrelated tones better than chance, while extending the result of Bregman and Campbell [J. Exp. Psychol.89, 244–249 (1971)] that subjects perform worse when discriminating the order of perceptually unrelated tones than when discriminating the order of perceptually related tones.

ISSN:0001-4966    

DOI:10.1121/1.2024039

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

Decrements in broadband noise stimuli were produced by changing the intensity of the noise for a brief interval. As the duration of the interval increases, less change in level is needed to detect the alteration. One can interpret these experiments as probing the impulse response of the auditory temporal mechanism in the manner suggested by Buunen and van Valkenburg [Jr. Acoust. Soc. Am.65, 534–537 (1979)]. Unlike their results, our measurements are well fit by an exponential function with a short (8–10 ms) time constant. Our results are consistent with the model proposed by Viemeister [Jr. Acoust. Soc. Am.66, 1364–1380 (1979)] to explain his results obtained with the modulation transfer function (MTF). Direct measurement of the modulation transfer function for these same listeners indicates good agreement between the time constant measured in the gap experiment and the low‐pass break point measured in the MTF. We also explored increments in the noise stimuli instead of decrements. The data show symmetry when the increase or decrease in the noise rms is used to express the change in the stimulus. [Work supported by a grant from the National Science Foundation.]

ISSN:0001-4966    

DOI:10.1121/1.2024045

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP

摘要:

This paper describes and demonstrates a pattern of tones with some remarkable properties. When played in one key, it is heard as ascending; yet, when played in a different key, it is heard as descending instead. When a tape recording is made of the pattern and it is played back at different speeds, the pattern is heard either as ascending or as descending, depending on the speed of playback. To add to the paradox, when the pattern is played in any one key it is heard as ascending by some listeners but as descending by others. This effect is shown to be robust in the face of a number of parametric manipulations. Implications for processes underlying pitch perception are discussed.

ISSN:0001-4966    

DOI:10.1121/1.2024050

出版商:Acoustical Society of America    

年代:1986

数据来源: AIP