Evaluation of airborne sound insulation in terms of annoyance degree

The single-number quantities (SNQs) characterizing the sound insulation is often inconsistent with the subjective perception of annoyance degree to the transmitted sound. The purpose of this paper is to establish the relationships between SQNs and the annoyance degree of transmitted sound. In this research, 25 types of walls with various spectral characteristics of sound insulation and 3 types of noises, namely speech, music and traffic noise, are adopted in subjective listening tests for rating annoyance degree. The testing results show that the standard weighted sound insulation index Rw combined with spectrum adaptation is strongly correlated with annoyance degree. The performance of the annoyance predictor is related with the incident noise spectrum, therefore the optimum ratings of sound insulation to speech, music and traffic noise are different. The frequency range included in SNQs has significant impacts on annoyance degree rating, which is related with the noise power spectrum. A-weighed sound level difference with an appropriate frequency range is an accurate rating indicator to the sound insulation in terms of annoyance degree. The results of this research can be used to improve the assessment and prediction of airborne sound insulation.