Preliminary work about the reproduction of sonic boom signals for perception studies

As part of a French research program, a sound restitution cabin was designed for investigating the annoyance of sonic boom signals. The first goal was to reproduce the boom spectrum and temporal waveform: this required linear generation of high pressure levels at infrasonic frequencies (110 SPL dB around 3 Hz), and response equalization over the full frequency range (1 Hz-20 kHz). At this stage the pressure inside the cabin was almost uniform around the listener, emulating an outdoor situation. A psychoacoustic study was then conducted which confirmed that the loudness (related to annoyance) of N-waves is roughly governed by the peak pressure, the rise/fall time, and the wave duration. A longer-term goal is to reproduce other aspects of an indoor situation including rattle noise, ground vibrations, and a more realistic spatial repartition of pressure. This latter point has been addressed through an Active Noise Control study aiming at monitoring the low-frequency acoustic pressure on a surface enclosing a listener. Frequency and time-domain numerical simulations of boom reproduction via ANC are given, including a sensitivity study of the coupling between a listener's head and the incident boom wave which combine into the effective sound-field to be reproduced.