Listening test of walking noise from 20 Hz in dwellings

Walking noise annoyance tend to be higher in lightweight than in heavy constructions, even with exactly the same measured impact sound level. The Swedish research program AkuLite indicated that the correlation between measured impact sound insulation and annoyance was significantly improved by extending current ISO evaluation methods from 50 Hz down to 20 Hz. Consequently, there is a need to develop new metrics of impact sound insulation that better correspond to the perceived sound quality. The objective of this study was to verify whether frequencies between 20-50 Hz are important for walking noise annoyance and to evaluate which impact sound level metric that best correlates with walking noise annoyance. The methodology was to evaluate annoyance based on binaural recordings of walking noise in a two-part listening test. The stimuli were reproduced using a combination of headphones and subwoofer. Two living rooms were evaluated, one lightweight wooden construction and one heavy concrete construction. Both rooms achieved similar weighted impact sound level when evaluated from 50 Hz, but the rated annoyance differed significantly. The need to consider frequencies down to 20 Hz in lightweight constructions was verified. The best correlation between measured impact sound level and subjective response was achieved when the evaluation range was extended down to 20 or 25 Hz using a flat frequency weighting factor.