Decoding XLR: More Than Just a Connector

If you've ever worked with professional audio or video equipment, you've likely encountered the ubiquitous XLR connector. But what does "XLR" actually stand for? The answer, surprisingly, is "External Line Return." While this might not immediately illuminate its function, it hints at the connector's role in balanced audio signal transmission.

What is XLR and How is it Used?

XLR connectors are the workhorses of professional audio and video. They're primarily used to transmit balanced audio signals, which are crucial for minimising noise and interference. This makes them ideal for:

• Microphones: Connecting microphones to mixers, audio interfaces, and recorders.
• Mixers and Amplifiers: Interconnecting audio processing equipment.
• Lighting Systems: In DMX lighting control.
• Video Production: For audio connections in professional video equipment.
• Stage Automation: In complex stage setups.

The key advantage of XLR is its ability to deliver a clean, robust signal, even over long cable runs.

A Brief History

The XLR connector was invented by James H. Cannon, the founder of Cannon Electric in Los Angeles, California. Initially, Cannon produced a series of three-pin circular connectors. He then made some key modifications:

He rearranged the pins and added a latch, creating the "XL" series.
Later, he encased the female contacts in a resilient rubber compound, resulting in the "XLR" series.
This evolution led to the reliable and durable connector we know today.

Identifying an XLR Cable

XLR cables are easily recognisable by their circular design and the presence of 3 to 7 pins. The most common variant is the 3-pin XLR.

The Industry Standard: 3-Pin XLR

The 3-pin XLR is the industry standard for microphone and audio signal cables. Its pin configuration is as follows:

Pin 1: Ground (shield)
Pin 2: Positive signal (hot)
Pin 3: Negative signal (cold)
This balanced configuration, along with the cable shielding, effectively reduces noise and interference. The locking mechanism ensures a secure connection, even in demanding environments.

RHJ Tech's XLR Solution: A Practical Example

To illustrate the practical application of XLR, let's consider RHJ Tech's cable. This cable is designed for use with dual-channel wireless microphone receivers, such as the Rode Wireless GO II, and cameras or recorders with XLR inputs.

Key features include:

• Dual low-profile 3-pin XLR male connectors.
• A right-angle 3.5mm TRS connector.
• Colour-coded caps for easy channel identification.
• A 40cm (15.7") cable length.
• Low profile connectors.

This cable provides a neat and professional connection, minimising clutter and ensuring reliable audio transmission. It is important to note the coloured insulation on the XLR end, and ensure that it will fit within your devices XLR inputs.

The XLR connector, with its "External Line Return" heritage, remains a cornerstone of professional audio and video. Its reliability, ruggedness, and noise-canceling capabilities make it an indispensable tool for professionals and enthusiasts alike.