6.18: XLR Cables

XLR Cables

The XLR connector is the professional standard for microphones. It provides a balanced connection that reduces noise and interference. XLR cables are durable and designed for long cable runs without signal loss.

An XLR connector is typically a 3-pin connector, sometimes referred to as a Cannon plug after its original inventor, James H. Cannon, founder of Cannon Electric (later purchased by ITT). The term “XLR” comes from the Cannon series that featured a latch (L) and rubber insulation (R).

The 3 pins are standardized as follows:

• Pin 1: Ground (shield)
• Pin 2: Hot (+, non-inverting)
• Pin 3: Cold (–, inverting return)

This balanced wiring helps cancel noise and interference over long cable runs, making XLR the preferred connector for professional audio.

There are two physical types of XLR connections:

• Male connectors: Found on microphones and equipment outputs. They have 3 exposed pins.
• Female connectors: Found on cables and equipment inputs. They have 3 recessed holes that accept the male pins.

This male-to-female design ensures a secure, noise-resistant connection and makes it impossible to connect them incorrectly.