Realism assessment of sonic boom simulators

Developments in small supersonic aircraft design are predicted to result in low-intensity sonic booms. Booms generated by current aircraft are similar to those that led to the ban on commercial supersonic flight over the US, so are unsuitable for parametric studies of psychoacoustic response to low-intensity booms. Therefore, simulators have been used to study the impact of predicted low-intensity sonic booms. However, simulators have been criticized because, when simulating conventional-level booms, the sounds were observed to be unrealistic by people experienced in listening to sonic booms. Thus, two studies were conducted to measure the perceived realism of three sonic boom simulators. Experienced listeners rated the realism of conventional sonic boom signatures when played in these simulators. The effects on perceived realism of factors such as duration of post-boom noise, exclusion of very low frequency components, inclusion of ground reflections, and type of simulator were examined. Duration of post-boom noise was found to have a strong effect on perceived realism, while type of simulator had a weak effect. It was determined that post-boom noise had to be at least 1.5 seconds long for the sound to be rated very realistic. Loudness level did not affect realism for the range of sounds played in the tests (80–93 dB ASEL).