Sonic-boom loudness test using new indoor sonic-boom subjective-test facility at NASA Langley Research Center.

A sonic-boom simulator at NASA Langley Research Center has been constructed to research the human response to low-amplitude sonic booms heard indoors. The facility’s initial goal is the development of a psychoacoustic model for individual sonic booms to be validated by future community studies. The current test assesses the suitability of existing loudness metrics for predicting indoor human annoyance to sonic-boom waveforms. The test signals consist of synthesized and recorded sonic-boom waveforms chosen to systematically vary the low-frequency content. Some waveforms are presented with and without high-pass filtering to examine the effect of low-frequency content on annoyance. Equally annoying presentation levels are determined among the test signals by paired comparison with a reference sonic-boom waveform. A second reference waveform is also used for some signals to examine if results change with the reference sound. Loudness metrics are then calculated for each measured test signal at the subjective-equality level. Loudness metrics are thus evaluated based on their ability to predict annoyance for a wide range of sonic-boom waveforms.