There is usually a lot of confusion when the subject of whether cables, particularly XLR cables, are mono or stereo, is brought up. This subject area can be very confusing for beginners and even professionals. I am going to speak about the issue of whether XLR cables are mono or stereo in this article, so read along.
XLR cables are primarily used to transmit a balanced mono audio signal from one device to the other. They can also be used for stereo signals. The only caveat is that when XLR cables are used for a stereo signal, the signal will become an unbalanced audio signal.
And as you may already know, unbalanced audio signals are prone to noise and audio degradation. So, in the rest of the article, I’llI’ll walk you through how XLR cables transmit mono and stereo signals and why they are more suited for mono signals.
But just to give some context, let me first talk about the key differences between mono and stereo audio.
Difference Between Mono and Stereo Signals
Mono is an abbreviation for monophonic, while stereo stands for stereophonic. As the name goes, mono signals are audio signals that are recorded and played back using a single audio channel. This simply means a mono cable is an audio cable that carries only one signal within it.
On the other hand, stereo signals are audio signals that are recorded and played back using two audio channels. In plain terms, a stereo signal contains two individual signals. Stereo sounds are produced using two or more independent audio channels.
This usually creates the impression of sound being heard from different directions.
The main difference between mono and stereo sounds basically lies in the number of channels used to record and playback the audio. Mono signals are recorded and played back using one audio channel, while stereo signals are recorded and played back using two audio channels.
Stereo signals are usually the better option. And that’s because it gives you a sense of space. In other words, it creates the illusion of hearing with both ears. They are usually preferred over mono when it comes to listening to music, in theatres, etc. Mono sounds are also preferred for public address systems, telephone networks, etc.
This, however, doesn’t make mono signals any useless. In fact, in a typical audio and music recording, many mono signals are recorded with a microphone. And then, some are panned to the left channel audio, and others into the right channel to create a stereo signal.
I think that’s enough on mono and stereo signals. Now let’s talk about XLR cables and how they are wired and work.
How Are XLR Cables Wired?
XLR cables are basically made up of 3 parts. These are the wires, connectors, and shielding. Typical XLR cables are composed of 3 wires that go down the cable. Two of these wires serve as signal wires and are responsible for transmitting audio signals, whiles the third wire serves as the ground wire.
The shielding in XLR cables is there to protect the audio signal being transmitted through the wires. This shielding protects the audio signal from external interference such as noise and hum.
XLR connectors come with a round end with three separate contact points. This means that XLR connectors come with three pins or holes, which serve as their points of connection. Most XLR cables consist of a female plug with three holes at one end and a male plug with three pins at the other end.
How XLR Cables Carry Mono Signal
John Gilder of Home Studio Corner made an excellent video explaining how balanced cables such as XLR carries mono signals, and you should check it out below.
Now here is how XLR cables transmit balanced mono signals. This may seem a little too technical, but follow me.
XLR cables have three wires in them. One is the ground wire, and the remaining two carries the actual audio signal. And as we have already mentioned, mono signals have only one channel of audio. This means you can run the mono signal through only one of the two remaining cables, leaving one of the XLR wires unused.
However, this makes the mono signal unbalanced and susceptible to noise and degradation. And we certainly don’t want that. So here is how XLR cables make the mono signals balanced.
The mono audio signal gets duplicated and runs through the two signal wires of the XLR cable. However, one of the signal’s polarities is flipped and becomes out of phase with the other signal at one end of the XLR cable.
As both identical but out of phase signals travel through the XLR cable, they pick up noise and interference. At the other end of the XLR cable, the audio signal that was flipped out of phase is flipped back in phase with the other signal.
When this happens, the noise picked up by both wires are out of phase, and they cancel each other, leaving only the clean mono signal from both wires.
The transmission of a balanced mono signal by XLR cables ensures that the signal that passes through them is preserved. As a result, the microphone audio signals that pass through XLR cables are virtually clean with little to no hum or interference.
Due to the balanced nature of XLR cables, they can be used for very long cable runs without having any noise interference.
How XLR Cables Carry Stereo Signal
XLR cable comes with a connector that is made up of three pins or sockets, as we’ve already mentioned. This is not enough to transmit balanced stereo signals. Due to having three pins, these XLR cables can only transmit unbalanced stereo signals.
A stereo signal is made up of two different signals that are meant to be routed through two different channels. Unfortunately, an XLR cable can be said to have only two “channels” in them. Hence, when a stereo signal is passed through a typical 3-pin XLR cable, the two signals get routed through the negative and positive wires of the cable.
This leaves no room for duplication of the audio signals. Due to this, stereo signals carried by XLR cables become unbalanced, making them susceptible to noise and interference.
Using Dual XLR Connectors To Receive Balanced Stereo Signal
It has been established that it is impossible to send a balanced stereo signal across a single 3-pin XLR cable. However, if you are eager to transmit a balanced stereo signal across an XLR cable, here’s how to go about it.
To send a balanced stereo signal through XLR cables, you need to use a dual XLR Male Y-splitter (like this one on Amazon).
This is essentially a cable that receives a stereo signal from a TRS connector, splits the left and right channel into two mono signals. And then, it routes them through two XLR cables individually. This means both the left and the right signals will be treated as a mono signal through these XLR cables, allowing you to have a balanced stereo signal.
This cable is very useful. It enables you to connect the output of your audio device, portable gadgets like laptops, or other line-level stereo devices to the inputs of a mixer or any other audio gear that comes with XLR connection inputs. For more information on XLR splitters and how well they work, read this article.
Are Balanced Cables Mono or Stereo?
Balanced cables come as mono cables and not stereo. They are primarily designed to carry only one independent audio signal, which is always duplicated in opposite polarity.
These cables are made up of 3 wires that go down the cable and are meant to transmit balanced mono audio signals. One of these wires serves as the ground while the other two positive and negative wires transmit two copies of the same audio signal.
Balanced audio cables include XLR and TRS cables. Aside from being balanced, they are mono cables as well. They always carry two copies of the same audio signal being transmitted. This is unlike stereo cables, which carry two different audio signals in the same cable.
Traditional XLR cables are able to transmit balanced mono signals perfectly and are not easily susceptible to noise and interference. This prevents noise and hum from entering your sound.
It is worth noting that; balanced mono cables can be used to transmit stereo signals. However, the stereo signals they transmit will not be balanced.
What Is the Difference Between Balanced and Stereo Cables?
Many people assume that the terms “balanced” and “stereo” are the same. Even though balanced and stereo cables are both designed to have connectors or plugs with three contact points and three wires inside the main cable, unfortunately, they are not the same.
The main difference between the two is that the term “balanced” deals with polarity, whiles the term “stereo” is concerned with the number of channels where an audio signal passes through.
Balanced cables refer to cables that have dual polarity when it comes to signal transmission. These cables allow for positive, negative, and ground wiring connections. On the other hand, stereo cables refer to cables that have multiple channels such that signal transmission is sent to either a left or right channel rather than a single channel.
The positive and negative wires in balanced cables transmit copies of the same signal but in different polarities. In stereo cables, the left and right channels transmit different signals.
There are balanced cables that are not stereo cables. A typical example of such cables is the XLR cable and TRS cable. These cables are balanced cables that are not stereo.
XLR cables are primarily designed to carry a balanced mono signal. These cables are designed to transmit one independent audio signal, which is duplicated in opposite polarity. Due to this, balanced signals are able to reject sound interference better than unbalanced signals.
XLR cables can be used to carry stereo signals as well. However, these stereo signals end up becoming unbalanced signals. Hence, it is not ideal to use these cables for transmitting stereo signals.