Subjective Preferences for Birdsong and Insect Song in Equal Sound Pressure Level

Yoshiharu Soeta,Hiroko Kagawa

doi:10.3390/app10030849

Yoshiharu Soeta, Hiroko Kagawa

Open Access

https://doi.org/10.3390/app10030849

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Abstract

Birdsong is used as a sound signal for visually impaired people in train stations in Japan. However, such sound signals were reportedly difficult to be localized by over 40% of visually impaired people. More than 40% of visually impaired people reported that such sound signals were difficult to identify. The sound pressure level of birdsong is typically low because higher levels of birdsong can cause annoyance to users or residents. Therefore, preferences for birdsong should be investigated. Importantly, birdsong and insect song have been shown to have a positive effect on soundscapes. However, preferences for different types of birdsong and insect song have not been investigated. The current study sought to clarify which types of birdsong and insect song are preferred, and to determine the dominant physical parameters that relate to the preference. We evaluated subjective preferences for various types of birdsong and insect song using paired comparison tests. The relationships between subjective preference and physical parameters were examined. The results indicated that Horornis diphone and Teleogryllus emma were the most preferred types of birdsong and insect song, both of which are common in Japan. The maximum peak amplitude of the autocorrelation function, determinants of which are pitch salience, loudness, and spectral content, such as centroid, flux, and rolloff, are significant parameters influencing subjective preference.

Highlights

Many kinds of sound signals are applied to convey information in Japanese public spaces
Teleogryllus emma is the largest Grylloidea in Japan, known colloquially as a cricket, and its song is often heard throughout Japan in autumn
Preferable birdsong and insect song stimuli and the dominant physical parameters related to preferences were investigated

Summary

Introduction

Many kinds of sound signals are applied to convey information in Japanese public spaces. These signals can be divided into three groups. Alarm signals are used to provide information about potentially life-threatening events. Attention signals are used to provide information about basic infrastructure, such as the locations of stairs, toilets, and ticket gates. The guidelines for improving the facilitation of transportation for passenger facilities of public transportation in Japan [1] recommend the use of simulated birdsong for attention signals that inform visually impaired people about the location of stairs in train stations. A previous study found that more than 40% of visually impaired people reported that such signals were hard to detect [2].

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