Acoustic comfort in large dining spaces

Highlights

• Determined the effect of background noise on the acoustic comfort of diners.

• Determined source types and dominant sounds affecting acoustic comfort.

• Determined affecting factors of dominant sound sources for acoustic comfort.

• Revealed the effects of demographic and social factors.

Abstract

This study carried out a questionnaire field investigation in two typical large dining spaces. The results suggest that the acoustic comfort of diners has an influence on the comfort evaluation of the overall dining environment, and background noise is an important factor affecting the acoustic comfort evaluation of diners. The role of various individual sound sources in background noise has been investigated, considering general background music, speech sound, activity sound, and mechanical noise, and it has been revealed that background music, other diners’ speech sound and tableware’s impact sound has a dominant impact on the acoustic comfort evaluation of diners. Compared with the existence of background music in background noise, diners’ acoustic comfort evaluation is higher than that without background music. The loudness, articulation, noise level and preference degree of various individual sound sources are factors which affect diners’ acoustic comfort evaluation on sound sources. In terms of demographic and social factors, gender and the frequency of dining out have a significant impact on diners’ acoustic comfort evaluation.

Introduction

In the field of urban soundscape, sociological approaches have been taken to conduct many studies on the soundscape in urban public open spaces including open squares, underground spaces, residential areas, hospitals, schools and historical streets [1]. Dining spaces are an important component of urban public spaces, and the quality of the internal sound environment determines diners’ comfort evaluation on the overall dining experience. This evaluation influences diners’ satisfaction with the restaurant as a whole and influences decisions such as whether to return and whether to consume more [2], [3], [4]. Existing studies on the sound environment in dining spaces have mostly been conducted from the aspect of speech articulation. Field research by Zheng & Zhang found a generally poor sound environment, relatively long reverberation time and low speech articulation in college canteens and put forward corresponding improvement strategies [5]. Kang & Lok found that the sound pressure level of background noise in dining spaces was 80–90 dBA [6]. In the case of certain reverberation time, unintelligible speech sounds could be expected to be a masking sound so that language communication of diners around the same table would not be disturbed by the noise of diners at neighbouring tables, but the sound pressure level threshold range of background noise which sheltered the noise interference of diners at neighbouring tables and guaranteed the speech articulation of diners around the same table was found to be relatively narrow, at around 69–71 dBA [7], [8], [9]. Kang carried out research into the sound environment of dining spaces from the aspect of speech articulation and proposed a strategy for improving speech articulation in dining spaces [10]. Acoustic comfort is an important aspect of diners’ comfort evaluation on the overall dining environment, but few studies are conducted from the perspective of acoustic comfort of dining spaces.

Studies on acoustic comfort depend on listeners’ perception and evaluation of their overall sound environment [11], [12]. Chen & Kang adopted the method of subjective evaluation of customers in city malls to determine factors affecting subjective evaluation of acoustic comfort, including objective acoustic indexes and some subjective factors, such as retention time, purpose and type of sound sources [13]. Meng & Kang conducted studies on acoustic comfort in underground commercial streets [14], [15]. They reached the conclusion that respondents’ social characteristics (e.g., education background, income, and educational level), subjective factors (e.g., retention time and visit frequency) and various individual sound sources were influencing factors in the subjective evaluation of acoustic comfort. The sound pressure level of background noise was an important objective index influencing acoustic comfort evaluation [16]. In studies on acoustic comfort in underground commercial streets, Meng [17] found that the sound pressure level of background noise had an influence on subjective acoustic comfort evaluation; the curve of correlation between subjective acoustic comfort evaluation and the sound pressure level of background noise presented a parabola form. When the sound pressure level of background noise was high or low, subjective acoustic comfort evaluation decreased. In their studies on acoustic comfort in dining spaces, Chen & Kang determined the threshold of sound pressure level of background noise in dining spaces when the acoustic comfort of diners was acceptable, which was 70–75 dBA [18]. Various individual sound sources in background noise had a remarkable influence on the acoustic comfort evaluation of listeners [19], [20], [21]. However, studies on the influence of sound sources on the acoustic comfort of diners are very few [5], [6], [7], [8], [9], [10].

Therefore, this paper, through a questionnaire survey in two typical large dining spaces, aims to examine the acoustic comfort in such spaces and their affecting factors. Firstly the general evaluation of the sound environment in dining spaces is examined, in particularly considering the role of background noise. Then the impact of different types of sound sources are examined and dominant sound sources are determined, and their affecting factors are then explored. This is followed by an examination of social and demographic factors’ effects.