1. 声的投射; 声投射：sound program transmission system == 音声放送中継方式 | sound projection == 声的投射,声投射 | sound proof box == 隔音箱

noun

1. the acoustic phenomenon that gives sound a penetrating quality

e.g. our ukuleles have been designed to have superior sound and projection
a prime ingredient of public speaking is projection of the voice

Synonym: projectionacoustic projection