オンマイク

noun

on-mike; on mic; live mic

Refers to a microphone being live or active, often used in broadcasting, recording, or performance contexts.

• 本ほん番ばん中ちゅうは常つねにオンマイクなので、余よ計けいな音おとを立たてないでください。

  The mic is always live during the performance, so please don't make any unnecessary noise.