Other researchers have built similar devices in the past, but they always required a precise setup where the sound source and reflector were at fixed "resonant" distances.
过去一些研究人员也做过类似的装置，但在事先总是需要精确设定确保声源和反射器在固定的“共振”距离。
3
Acoustic reflector is widely used in dome speaker for sound energy dispersion redistribution.