Propagation of Sound across Audience Seating

Abstract

Measurements have been made in four concert halls, and on scale models of the seats alone, of the attenuation of sound passing at grazing incidence over the seating area. For low-frequency sound, we find attenuation in excess of inverse-square loss, which amounts typically to 15–20 dB; the attenuation is considerably less at frequencies lower and higher than about 150 cps, the frequency of maximum attenuation. This attenuation attains its maximum severity after about 12 seat rows, beyond which little further degradation occurs. It appears to be an interference effect and does not depend markedly on the absorptive properties of the seats. The frequency of maximum attenuation is related primarily to the height of the seats and only secondarily to the row-to-row spacing. This low-frequency loss occurs in all the halls that we have measured, and we believe it to be typical of the main-floor sound of all concert halls.

An Exploratory Analysis of Sound Field Characteristics using the Impulse Response in a Car Cabin

“…One-way ANOVA indicated significant effects of the frequency on G values (p < 0.01). This attenuation at lower frequency has not been observed in concert halls, churches, or temples [43][44][45] although the attenuation at lower limited frequency by seat dip effect was observed in concert halls and theaters [46][47][48]. …”

Perceptual significance of seat-dip effect related direct sound coloration in concert halls

“…1 Furthermore, in halls where the reflections are insufficient to level the initial SDE, the design of the seating area might be more critical. Given that the narrow filter represents a concert hall with closed seats and raked floor, and the wide filter a concert hall with open seats and a flat floor, both preference test results favor the former design.…”

“…However, the general usability of the threshold obtained by Davies et al has some limitations: (1) In their study, the SDE is confined to one octave band (200 Hz) while the variety of SDE spectra encountered in real halls span more than one octave band. In addition, identical SDE are applied for the direct sound and SDE-filtered reflections, while in reality the reflections are affected differently.…”

“…[1][2][3] This phenomenon, called the seat-dip effect (SDE), colors the spectra of both the direct sound and some of the early reflections. The SDE varies with the direction of arrival, [1][2][3][4] and therefore the direct sound and the early reflections can have quite different lowfrequency spectra.…”

Virtual Acoustics

“…Furthermore there are doubts that wave effects can be neglected above the Schroeder frequency. The is related to pronounced wave effects which correspond not to the statistical features in the room transfer function but rather to the local wave effects, such as the seat dip effect, which depends in the spacing and the height of seating and the shoulders of sitting persons in the audience (Schultz, Watters, 1964). Two large-scale projects of ongoing research in virtual room acoustics should be mentioned, "SEACEN" and the study of the research group led by Lokki (2013).…”