Optimized single-number quantity for rating the airborne sound insulation of constructions: Living sounds

Abstract

ISO 717-1 [(1996). International Organization for Standardization, Geneva, Switzerland] and ASTM 413 [(2010). American Society for Testing and Materials International] define various single-number quantities (SNQs) that are commonly used to rate objectively airborne sound insulation of constructions. Recent psychoacoustic evidence suggests that none of them is appropriate for a wide range of living sound stimuli. The purpose of the study was to develop an alternative compromising SNQ for the frequency range 50-5000 Hz that explains well the annoyance caused by various airborne living sounds transmitted from the neighboring dwelling. Optimal reference spectra for different living sounds were found by mathematical optimization. Experimental data from a psychoacoustic laboratory study [Hongisto, Oliva, and Keränen (2014). Acta Acust. Acust. 100, 848-863] were utilized. The subjects (n = 59) had evaluated the disturbance of living sounds that were electrically filtered to mimic transmission through commonly used wall structures. To find a high-performing reference spectrum for living sounds in general, the optimized reference spectra were averaged over all sound types. The resulting SNQ was called R + C. The related reference spectrum deviates significantly from the reference spectrum for living activities, C, below 315 Hz. The suggested SNQ correlates better with the subjective disturbance caused by living sounds than any of the present standardized SNQs of ISO 717-1 or ASTM 413.

Review of acoustic comfort evaluation in dwellings: Part III—airborne sound data associated with subjective responses in laboratory tests

“…Furthermore, the different types of sound stimuli are highlighted as an important parameter in some studies 10,13 because speech sounds have more high-frequency content while low frequencies are dominant in music sound stimuli. There are variations of course, for the cases of different sounds tested and responses.…”

“…This review demonstrates that different descriptors work better for various stimuli. However, in Virjonen et al 13 and Rasmussen and Rindel, 14 a spectrum adaptation term is suggested to formulate the measure: R C w opt + which predicts well most airborne sound types (except baby cry) within the full measurement spectrum of 50-5000 Hz and it is different to the standardized adaptation term C 50 5000 − . In some cases, the study design parameters are problematic: the sample size of listening tests can be small as in Pedersen et al 7 and Vian et al 8 or extremely small as in literature.…”

“…Several publications were subsequently found as references of the first selected papers. This review article includes 11 studies: eight European studies, [3][4][5][6][7][8]12,13 one Asian study, 9 and two Canadian studies. 10,11 In overall, 37 papers were found during the search in databases or relevant references and were evaluated by title name, abstract reading, and full reading.…”

“…[3][4][5][6] In some other cases the characteristics of noise types might influence in various ways the perception of subjects: thus different standardized descriptors work better for various sound sources. [10][11][12][13] Therefore, the relation of the measured acoustic data to self-reported responses is important to study. The level of association is explored with statistical analyses comparing objective and subjective data.…”

“…Another conclusion is that R C (R 2 = 0.93) and R C w + − 50 5000 (R 2 = 0.93) predicted the loudness response best, whereas the last two SNQs predicted best also the disturbance and acceptability ratings contrary to some previous studies. 12,13 Overall, the response for living sound types with flat spectrum seems to be predicted best by R w , STC , and SNQs which ignore frequencies below 100 Hz showing R 2 values around 0.9, while for noise types with dominant higher frequencies, such as baby cry and dog bark the best predictors were R speech , STC, and STC no8 . All the presented results were found statistically significant (p < 0.05).…”