Effects of secondary rattle noises and vibration on indoor annoyance caused by sonic booms

Abstract

For the past 40 years, commercial aircraft have been banned from over-land supersonic flight due to the annoyance caused by sonic booms. However, advanced aircraft designs and sonic boom prediction tools suggest that significantly quieter sonic booms may be achievable. Additionally, aircraft noise regulators have indicated a willingness to consider replacing the ban with a noise-based certification standard. The outdoor noise metric used in the certification standard must be strongly correlated with indoor annoyance. However, predicting indoor annoyance is complicated by many factors including variations in outdoor-to-indoor sound transmission and secondary indoor rattle noises. Furthermore, direct contact with vibrating indoor surfaces may also affect annoyance. A laboratory study was recently conducted to investigate candidate noise metrics for the certification standard. Regression analyses were conducted for metrics based on the outdoor and transmitted indoor sonic boom waveforms both with and without rattle noise, andincluded measured floor vibration. Results indicate that effects of vibration are significant and independent of sound level. Also, the presence or absence of rattle sounds in a transmitted sonic boom signal generally changes the regression coefficients for annoyance models calculated from the outdoor sound field, but may not for models calculated from the indoor sound field.