The XLR connector is a three-pronged plug and socket cable end used to network professional audio equipment. It performs duty as an industry standard for analog and digital sound elements such as cables and DMX512 components. First design by Canon, it takes its name from the original X connector, which was later modified with a release latch (L) and rubber seal (R). Most commonly used for analog audio, this connector locks into its port with a balanced connection. A ground pin adds safety and reduces unwanted interference when plugged in during a live performance.
Designed for male and female type connectors, the XLR connector represents an international standard for this type of audio component. While it may possess up to seven pins, three pins are most common. It may be mounted to a cable or chassis, as for a rack-mounted audio component. The finger-width, cylindrical XLR connector attaches to a cable and may feature male pins or female sockets, as with the panel connectors. A typical three-pin XLR connector employs a balanced connection to minimize undesirable electrical contact with high-voltage equipment.
Typically, the first pin represents the chassis ground and usually makes contact before the other pins. The second pin represents the positive polarity terminal; this is the hot pin. The third, or cold, pin is called the return terminal. Together, these two pins are the source of the audio signal. Before this innovation, two-pin, hot connectors were common.
One of the most frequent applications of the XLR connector is to connect microphones to public address systems. Technologies like condenser microphones may require the use of an onboard battery to supply power. The XLR connector can supply this voltage, referred to as phantom power. Usually, this power supply is fed through the first, or ground pin. Such versatility permits the widespread use of this connector while minimizing potential damage to sensitive microphone equipment.
Other products designed for the XLR connector standard may feature rectangular chassis and right angle style plugs. Like the straight connector, these may feature male or female attachments. They may also vary in pin number.
Four-pin connectors are often used for intercom headsets, and five-pin types are employed in dual-element or stereo microphones and headsets. Six-pin types fit dual-channel intercom systems. Seven-pin connectors serve remote controls for fog machines and other analog components. Employing XLR connector components can help ensure trouble-free audio setups and safer, noiseless component switching.