sound check
noun [ C ] uk/ˈsaʊnd ˌtʃek/ us/ˈsaʊnd ˌtʃek/
（尤指演出前对乐器及录音设备的）校音
a test of the musical instruments and recording equipment at a music show, especially before the players come on stage, to make certain that everything is working and that the sound quality is good