talkback
A talkback is a microphone-and-receiver system installed in a recording/mixing console for communication between people in the control room and performers in the recording studio. Most semi-professional and professional consoles include such a system. The typical setup includes an internal microphone built directly into the console, and a series of switches. The switches allow the recording engineer to route the microphone signal to a variety of audio paths in the studio, such as the performer's headphones, a set of speakers in the recording area, or directly to a tape recorder. Using this tool, the engineer can communicate with a performer with headphones while they are performing in the studio without interfering with the recording. Another use is to announce the title or other relevant information at the beginning of a recording (called a "slate").