Introduction
XLR connectors, a mainstay in the professional audio industry, are increasingly finding their way into prosumer applications, such as podcasting, social media content creation and home recording studios. Despite their superior audio quality and noise immunity, understanding and using XLR connectors can present unique challenges. This article aims to explore these hurdles, providing an educational and nuanced understanding of the role of XLR connectors in prosumer applications.
Origins
Instantly recognizable, the XLR connector greets you with a happy, mildly surprised 3-pin happy face! In the 1950s, the connector and its variations satisfied a need for sturdy, robust point-to-point connection of balanced audio signals around studios and music venues. The cast metal shroud and optional locking mechanism means an accidental kick (or aggressive microphone gymnastics!) would not disrupt the audio feed.
Balanced audio, with its inherent robustness in the face of common mode interference, was the basis, with an associated GND pin, as well as the (separate) chassis GND which extended the shield of the cables used (but is isolated from the 3 conductors in the cable). The XLR quickly established itself as the connector of choice for long runs of point-to-point audio in professional applications.
Standard / traditional audio usage
There are four basic types of XLR connector:
- Chassis socket
- Chassis plug
- Inline socket (one end of a cable)
- Inline plug (the other end)
In order to make audio connection somewhat foolproof, the basic assumption is that if you see an XLR with pins pointing at you, there is a signal SOURCE on the other end; if you see an XLR “face” with receptacles, that will be an expectant input to a device or system. Therefore, almost all cables have a socket on one end and a plug on the other (so are inherently directional). Similarly, for audio equipment interface panels, chassis XLR sockets are inputs; if a chassis XLR has pins pointing at you, that’s an audio output. The directional cable trick also means that you can easily extend a run by connecting multiple shorter cables. Great for Music venues or sound reinforcement where the equipment setup varies with venue!
The other item to be aware of is pin assignment:
- Pin 1 = GND
- Pin 2 = audio +
- Pin 3 = audio –
Note that in balanced audio installations, it can be frustratingly easy to invert the phase of the audio; hence the need for consistency on the cables & pinout for preserving absolute phase (+/-) of the audio signal throughout the signal path.
Mechanically, Pin 1 on the plugs is extended slightly so that the GND connection makes first contact on insertion, establishing a common potential between pieces of equipment, preventing potential damage of audio I/O circuitry upon connection.
XLR’s Expansion into Prosumer Applications
As the home recording industry blossoms, with higher quality audio capture & editing becoming much more affordable, the demand for professional-grade equipment interfacing is on the rise. This increase in the ability to capture a performance leads Prosumers wanting to use studio grade peripherals, such as DI boxes and microphones, which already are available as standard with XLR connectivity. Naturally, Prosumer Audio Interfaces started to offer XLR connections (mirroring the professional equipment), to realize the same benefits inherent to professional studios: superior audio quality and reliability. However, this migration isn’t without obstacles.
Adapting to a New Paradigm
Prosumer audio setups often encompass a blend of professional and consumer equipment, which can create compatibility issues. For instance, while many high-quality microphones utilize XLR connectors, not all recording devices or computers offer XLR inputs. Also, musicians want to be able to record instruments directly to mix with vocals – which requires a different connector on the Audio Interface. Rather than add multiple connectors, some Audio Interfaces use a combined XLR and TRS (1/4” jack) input socket – which keeps cost and front panel real estate down – but does create a set of electronic compatibility headaches for the front end circuitry!
XLR Microphones in Home Studios
Professional grade XLR microphones are becoming increasingly popular in home studios, typically offering superior audio quality compared to their USB counterparts. However, these microphones often require phantom power, typically supplied via an audio interface or mixer with XLR inputs, making use of the 3 pin XLR connectivity to remotely power an input capture device. This introduces a challenge for users who must navigate the complexities of audio interfaces, phantom power, and gain settings to properly use an XLR microphone.
The Need for Audio Interfaces
As touched on earlier, using microphones requires an audio interface or input device capable of supplying phantom power and performing the necessary conversion from analog to digital signals. Choosing and operating this equipment to optimize performance can be daunting for novices. Understanding gain staging, monitoring levels, overload behavior and clip avoidance requires a level of technical knowledge often unfamiliar to the prosumer market. The XLR connector is a welcome, easily understood “standard” with very little nuance to establish basic audio signal routing.
Practical Constraints
Having listed the numerous advantages of XLRs, practical constraints for Prosumer in-home use can temper adoption. XLR cables are generally thicker and less flexible than their USB counterparts, which can be cumbersome in a home studio environment. USB based mics are improving all the time, and – somewhat like the XLR – offer a universal connectivity. Plus, the cost of decent XLR cables and equipment can be a barrier to entry, despite the significant audio quality improvements they offer.
Overcoming These Challenges
Despite these challenges, the audio industry has made strides in simplifying the integration of XLR connectors into Prosumer applications. Comprehensive education resources, more affordable Audio Interfaces, and easy-to-use software are all playing a part in bridging the gap between professional and Prosumer audio. Furthermore, the undeniable quality improvement and range of choice of XLR microphones over standard USB options reinforces their value proposition.
Upcoming Revolution for XLR Connectors
The use of XLR connectors in Prosumer applications, while presenting a unique set of advantages and challenges, enables a trend towards higher audio quality in home recording and podcasting. As understanding grows and technology advances, it’s clear that XLR connectors will continue to play a significant role in this evolving landscape. With informed equipment choices and a bit of technical know-how, users can effectively navigate these challenges to realize the full potential of their audio and vocal endeavors – with easily understood audio signal routing and connectivity!
With the growing desire for high quality audio capture, coupled with digitally controlled gain and signal optimization, it is crucial to recognize the role of factors like high-performance audio pre-amplifiers. Committed to this vision, Triad Semiconductor provides professional-quality integrated circuit audio solutions, ensuring studio-level audio for professional, prosumer, and consumer environments.
Triad Semiconductor’s XLR solution is coming soon! To be the first to hear, sign up now:
The History of the XLR Connector: From Broadcasting to Professional Audio
