An annoyance-related SNQ for the assessment of airborne sound insulation for urban-type sounds

Resumen

The sound insulation provided by a certain construction element is usually presented through Single-Number Quantities (SNQs). These SNQs are global values used to summarize the sound insulation that a construction element has as function of the frequency. Although there are standardized SNQs, whose calculation is described in the ISO 717–1 and ASTM E413-16 standards, there is not enough agreement on whether these SNQs are representative of the way humans perceive. The purpose of this research is to assess the degree of correlation between the annoyance perceived by humans and the most relevant existing SNQs for a set of façade insulation elements and urban-type sound samples. Likewise, the purpose is also to evaluate whether certain frequency bands have more influence than others on the perception of annoyance. Furthermore, to propose a reference curve for the calculation of a SNQ that is representative of the annoyance perceived by humans when faced with sounds of an urban nature. To this end, a 2-alternative choice (2-AC) listening test was carried out by 119 participants. In this test, participants had to listen to stimuli in pairs and select the stimulus that was most annoying to them. The stimuli were obtained by filtering different sound samples with the sound insulation of different construction elements. In particular, five sound samples were used for this listening test: four urban-type sound samples as well as pink noise. Also, the sound insulation of six façade insulation elements was used. The results of this listening test were then analyzed using Thurstonian models and the distance measure d’ (d-prime) was obtained for each comparison. Finally, an optimized reference curve for urban-type sounds Lopt-urban was calculated based on the results of the listening test by means of a Sequential Quadratic Programming (SQP) optimization algorithm.