Annoyance caused by heavyweight floor impact sounds in relation to the autocorrelation function and sound quality metrics

This study investigated objective and subjective evaluations of heavyweight floor impact sounds. The autocorrelation function (ACF) parameters and sound quality (SQ) metrics were used to explain the annoyance of heavyweight floor impact sounds. Sounds were generated by a bang machine and an impact ball and were measured in various rooms in apartments with different sound insulation treatments. Annoyance caused by the heavyweight floor impact sound was evaluated using the paired comparison method, with a wide range of objective measures. The effects of the objective measures on annoyance were examined by multiple-regression analysis. The relationship between annoyance and ACF parameters showed the following to be important for evaluating annoyance: sound energy Φ(0), variances of Φ(0) and the maximum ACF amplitude φ1. In terms of SQ metrics, the important factors for evaluating annoyance were loudness and fluctuation strength. The results showed that floors with viscoelastic damping material reduced Φ(0) or loudness. Viscoelastic damping material also reduced φ1, which is related to the dominance of the resonance frequency of the floor slab structure and its harmonics. Reduction of the floor impact level at the resonance frequency by viscoelastic damping material resulted in high sharpness.