XLR connector
What is XLR connector ?
Balanced audio is a method of interconnecting audio equipment using impedance-balanced lines. This type of connection is very important in sound recording and production because it allows for the use of long cables while reducing susceptibility to external noise.

Balanced connections use three-conductor connectors, usually the XLR type, which can optimize audio playback by eliminating any noise which may be present in the signal. XLR connections are most commonly found on high-end amplifiers, pre-amp/ processors, and CD players.
XLR connector