I am pretty sure you have heard a number of things about audio cables. Certainly, by now, you should know we are using them to connect the rest of our equipment, transfer audio signals (most of the time) and route them accordingly so we can either process them further or listen to them on our speakers.
Audio cables can take many forms and choosing the ones that are fit for our purpose strictly depends on the practical application we want to use them for. For example, you will rarely find cables that carry amplified signal in a recording studio unless there is a very specific usage for them.
Tip: Treat audio cables as any other piece of equipment you own. Their role might seem to be in the background; however, they are vital for your studio as every cable you might add to your setup, can potentially add noise to your audio output. Ideally you want proper cable quality and sturdy plugs.
In this article we will have a quick discussion the most common audio cables you can find around as it’s a good start to get you into the audio cable world!
We are going to also discuss about what balanced and unbalanced audio signals are, and what is their difference when carrying audio. Actually, let’s dive into this right away as it’s going to be fundamental to your understanding of the cables and their roles.
The balanced type allows the signal to be protected from external Radio Frequency (RF) interferences or noises (like hums and buzzes) from electrical circuits in a much better way than the unbalanced types. This requires 3 separate conductors for the signal to be transferred and protected. These conductors, carry the Hot (+), Cold (-) and Ground (G) signals all the way to the other end.
Essentially what happens is that any type of noise that makes it into the cable, is cancelled on the other end on the input. This is because the signal runs in phase reverse on the Cold conductor and reversed back to positive phase on the input. Meanwhile, any noise that makes it through the cable is in phase on both conductors. When the signal is reversed back to positive phase, the noise cancels itself and the result is a clear audio signal. So, as you can imagine, balanced cables are a “MUST” for any studio setups, home or not, as they can eliminate a lot of the unwanted noises. Ideally, we want to be using balanced audio for any cable that runs over 5 meters long, if possible, as the longer the cable gets, the more compromised it becomes to all the unwanted interference and noises I mentioned above.
The unbalanced type is a simpler technology. These cables only have 2 conductors, however they still carry Hot (+), Cold (-) and Ground (G) signals as the balanced connections do. What is the difference then? Out of the 2 conductors, one is carrying the Hot signal, the other is carrying the Cold AND the Ground signals. This is what makes the unbalanced cables more vulnerable to noise and interference. Cold and Ground running on the same conductor does not allow room for the noise to be cancelled. It is worth mentioning that the Cold/Ground conductor does act as shielding as well, but cannot eliminate the noise once it has passed into the conductor carrying the Hot signal. This is why unbalanced cables tend to be short. It’s the compromised solution to avoid noise and interference.
Tip: If you have any equipment that handles unbalanced audio, you might want to check their input levels as some specific units handle different signal levels than others. Make sure you are using balanced and unbalanced audio cables properly as a lot of noise and distortion can be due to mismatched gain between equipment due to incorrect cables being used.
Cable types
Let’s see if these type names ring any bells for you!
- XLR
- RCA
- TS
- TRS
- TRS 3.5mm
- TRRS
In any case, bells or not, let’s dive right into their specifics.
XLR
XLR cables carry balanced audio
XLR’s are the most common audio cables for carrying balanced audio signals under long distances. The XLR plug (male) is used on microphones as an industry standard and in multiple analogue and digital devices in the professional audio world.
XLR’s are also used as interconnect cables between powered speakers. XLR is not being used to carry powered signal, therefore they cannot be used with passive speakers.
XLR’s may carry electric power up to 48 volts, which you might know already as Phantom Power. Phantom Power is used to power condenser microphones or any other device can operate at that voltage, like the DI boxes.
More on Phantom Power and DI boxes in future articles
XLR’s have 3 conductors labels as 1 (G), 2 (Hot/+) and 3 (Cold/-). At this point, it’s worth mentioning that if an XLR cable has a TRS plug on the other side, the conductors have to be soldered in a specific way:
1 (Ground) to S (Sleeve)
2 (Hot/+) to T (Tip)
3 (Cold/-) to R (Ring)
Special mention to the mini XLR plug which can be found on other types of professional audio equipment such as headphones and wireless microphone transmitters.
RCA
RCA cables carry unbalanced audio
RCA’s are also called “Phono” and they are the most common type of audio plug cable you might find around a home consumer setups. Their name originates from the abbreviation of “Radio Corporation of America”, as they were the first ever company to produce and use this cable design.
You can find single RCA cables (sometimes coloured Yellow for video as they can carry video as well as digital signals but more on this an a separate article), but most of the times you’ll encounter them in pairs, colour coded as white and red, respectively for Left and Right channels.
RCA’s have 2 conductors; the Tip where the audio signal is transferred via the centre pin conductor and the Sleeve which provides the ground via the outer ring.
In the next section I will discuss about TS and TRS. People will, very frequently, refer to TS cables as Mono cables and to TRS as Stereo cables.
Although there is some logic behind this, it is not always correct and this creates confusion. I am going to explain why TS Mono, TRS Balanced and TRS Stereo are 3 completely different cable implementations.
TS
TS cables carry unbalanced audio
TS are also known as “Jack” cables. They are the common cables you will use to connect to your guitars and basses in order to get to your amp or pedals. TS stands for Tip and Sleeve, which correlates to the plug’s connectors.
Like RCA, these ones have only 2 conductors which carry the audio signal and ground respectively. This is easy to tell by the black separator on the plug which essentially splits it into 2 connectors for the conductors.
TS cables should not be exceeding 7 meters in length as the unbalanced cables, although shielded, are very vulnerable to interference and noise as we mentioned earlier.
Of course, they can only carry Mono audio.
TRS
TRS cables carry balanced but they can also carry unbalanced audio if they are used as stereo cables
Either you are a producer, engineer, musician or even just a music fan, it doesn’t matter. With a little attention to detail, you definitely can recall yourself spotting these cables around.
The TRS initials stand for Tip, Ring and Sleeve, similarly like TS, referring to the plug’s 3 distinguishable connectors for its 3 conductors. Interestingly enough, the devices where a TRS cable will be connected to, will determine how the cable will be used.
Scenario A: As a TRS Balanced Mono cable. In this case the cable will have the exact same behaviour as an XLR cable. The 3 conductors will carry a mono audio signal as per below:
Tip – Hot (+)
Ring – Cold (-)
Sleeve – Ground (G)
Like the XLR, when the signal is transferred to the end device, Cold will be reversed, cancelling any noise that has made it through the cable.
Scenario B: As a TRS Unbalanced Stereo cable. In this case the cable will use the 3 conductors to carry a stereo signal this way:
Tip – Left Channel
Ring – Right Channel
Sleeve – Ground
In this scenario, only one conductor is used to carry each audio signal, which means any noise that will interfere with the cable, cannot be cancelled out and, therefore, makes the cable act as an unbalanced cable.
Balanced TRS will be used in a studio as most professional equipment will use either XLR or Balanced TRS outputs, such us audio interfaces, monitor speakers and studio controllers.
Unbalanced TRS is usually used on headphone outputs where a stereo signal is required, but it does not necessarily need to be in a professional environment.
TRS 3.5mm
TRS 3.5mm cables carry unbalanced audio as they are used for stereo configurations
Not much to add here. the TRS 3.5mm is a smaller version of TRS. Very broadly used in consumer audio, you can spot it in any headphone jack, and its conductors would follow the below setup:
Tip – Left Channel
Ring – Right Channel
Sleeve – Ground
TRRS
TRRS cables carry unbalanced audio
TRRS are no other than the plugs everyone uses for their mobile headphones and have a microphone on them. These are not intended for professional audio, although it’s great to know the idea behind them.
Having 4 conductors on a 3.5mm jack is no easy feat. But an easy way to remember what goes where, is to compare TRRS with the unbalanced version of a stereo 3.5mm jack. As I mentioned above, the TRS 3.5mm Jack conductors would be:
Tip – Left Channel
Ring – Right Channel
Sleeve – Ground
The principle is the same for TRRS although there is a second ring for carrying the Ground, and the sleeve is now carrying the microphone signal.
Tip – Left Channel
Ring – Right Channel
Ring – Ground
Sleeve – Microphone
This is the most common implementation on the TRRS plug. There are other implementations for audio (due to different manufacturers), and a few of others are designed to carry video with audio, but I am not going to discuss further about them on this article.
Hopefully you managed to get some knowledge out of this article in regards to audio cables and their signals and now you should be able to make the right choice in which cable to choose for any designated purpose you want to use it for!
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Till next week, take care!
