When someone mentions audio cable, the first thing that comes to an average consumer’s mind is some common audio cable type, like an AUX cable, RCA, or optical cable. However, the world of audio cables is much bigger and more confusing than that.
You don’t have to be an audio expert or sound engineer to know that each piece of audio gear requires matching audio cables. And I’m not just referring to the connector type or size. The cable configuration is just as important.
Some audio equipment requires balanced, while other gear requires unbalanced cables. Some can only receive digital audio; other is fully analog.
This guide is designed to make the world of audio cables a bit less intimidating. I will try to list all the most common audio cable types used in home and professional audio setups and explain the intended purpose and possible use scenarios for each cable type.
Furthermore, I will explain the differences between analog and digital cables as well as balanced and unbalanced cables. Finally, I’ll give you some useful tips on what cables to look for depending on your intended purpose.
Let’s start with some basic terminology.
Jacks and Plugs – Female and Male Connectors
This is not exactly a mystery, but it could create some confusion. So, let’s clarify things. The image below explains everything.
The fixed part of the connection is called JACK. What you plug into a jack is called PLUG. Jacks are usually female connectors (F connectors or F sockets), while the plugs are male connectors (M connectors or M sockets). Every plug requires a matching jack.
Balanced and Unbalanced Audio Cables
The story about balanced and unbalanced cables is a bit more complicated than the story about jacks and plugs. But it’s not impossible to comprehend.
Some audio cable types can be both balanced and unbalanced, depending on the purpose, while others are always unbalanced. The primary difference between balanced and unbalanced cables is not just in the connectors. The most important difference is in the configuration/geometry of the cable.
Inside an unbalanced audio cable that transmits mono signals, you have one wire/conductor transmitting audio signal and a shield that doubles as the ground.
Inside a balanced audio cable, you have two wires, each transmitting the same audio signal, and a shield that doubles as the ground.
Two wires inside a balanced cable transmit the same audio signal, but the signals are shifted in phase by 180°. The original signal is usually called the hot signal (+), while the signal with reversed polarity (phase-shifted signal) is called the cold signal (-).
Because of the 180° phase shift, two signals cancel each other out while traveling down the cable.
While the signal travels down the wires, the cable can also pick up noise caused by electromagnetic (EM) or radio frequency (RF) interference. This interference is induced by all kinds of electronic devices surrounding the cable.
The noise is added to both conductors/wires inside the cable and travels along those wires with hot and cold audio signals. While the audio signals traveling along the wires have reverse polarity, the noise waves in both wires are in-phase (they are exactly the same).
When audio signals reach the destination device, which also has a balanced input stage, the device only amplifies the difference between the two audio signals. Since the noise signals are exactly the same, they will not be amplified. Instead, they will be rejected. This process is called Common Mode Rejection.
Because the noise signals are common for both wires, the balanced input stage of the receiving device rejects that noise and only amplifies the incoming audio signal.
To simplify things, imagine the cold signal (the out-of-phase signal) being flipped in polarity once again by 180° at the input stage of the receiving device. That way, you get the original audio signal traveling along both wires, while the noise signals are opposite (out of phase), and they cancel each other out. So, the noise gets eliminated.
Unbalanced cables will always pick up more noise than balanced ones because the only protection against interference in unbalanced cables is shielding. However, that doesn’t mean that unbalanced cables are bad for all applications. In fact, unbalanced cables are used for most home applications.
The difference in performance between unbalanced and balanced cables over short distances (up to 10f) is not always noticeable. It could be, but it usually isn’t. When the cable is longer, the difference becomes painfully obvious.
Another reason people don’t use balanced audio cables for their home audio setups is the price of the balanced cables. And not just that – balanced cables need to be used with the appropriate (and expensive) equipment. You need an output device with a balanced output stage and an input device with a balanced input stage.
|BALANCED AUDIO CABLES||UNBALANCED AUDIO CABLES|
|¼” or 3.5mm TRS (mono audio)||¼” TS|
|XLR||¼” and 3.5mm TRS (stereo audio)|
|¼” and 3.5mm TRRS (stereo, no mic)||¼” and 3.5mm TRRS (stereo + mic)|
|Balanced Headphone Cables||SpeakON|
|Dual 3-Pin XLR|
|2.5mm TRRS Cable|
|4.4mm 5-Pole Pentaconn (Sony)|
Balanced cables are used in professional and audiophile setups. They are also crucial for mic-level signals because they are particularly weak and need to be more noise-free than any other type of audio signal. We will discuss different audio signal levels and the way different signal levels are handled later on.
Difference Between Balanced and Unbalanced Audio Cables
Analog and Digital Audio Cables
Both analog and digital cables have the same purpose – to carry audio information. What’s different is the geometry of the cables and the form in which that audio information is transferred.
Analog cables use electrical impulses, while digital cables transfer digital information in binary form (1s and 0s). Both audio cable types are designed for specific purposes and shouldn’t be mixed. You shouldn’t use analog audio cables instead of digital and vice versa. This will not damage your equipment, but the results won’t be perfect.
This is especially important when using analog cables where digital cables are needed. Digital cables are designed to work at a certain impedance (e.g. 75Ω digital coax audio cable with RCA connectors or 110Ω AES/EBU cable). Impedance is very important for digital signal transfer.
Analog cables are not optimized to work at a certain impedance as digital, which could affect the jitter and distort the audio signal.
Digital cables, on the other hand, can be used where analog is needed, even though they are not optimized for analog audio. The sound output, in some scenarios, can be surprisingly clean.
Still, I believe it’s safer to use digital cables when transmitting digital audio information or analog audio cables when transmitting analog audio.
It’s important to note that some digital and analog cables may look the same at first glance, even though they are intended for different purposes. For example, a traditional RCA analog cable and a digital coaxial cable with RCA connectors are very similar. Also, balanced analog XLR cable and AES/EBU cable with XLR connectors are practically the same.
Types of Audio Cables and Cable Connectors
Now that you are familiar with the basics, let’s dive deeper and see what types of audio cables and cable connectors exist and what they can be used for.
To make things easier, I have divided all the cables into two sections – ANALOG audio cables and DIGITAL audio cables.
|ANALOG CABLES||DIGITAL AUDIO CABLES|
|TS Cables||S/PDIF Optical TOSLINK Cable|
|TRS Cables||S/PDIF Digital Coaxial Cable|
|TRRS Cables||USB Cables|
|RCA Cables||HDMI Cables|
|Speaker Cables||MIDI Cables|
|XLR Cables||ADAT Cables|
Analog Audio Cables
If you prefer a digest version, you can find the most important information about each cable type in the infographic below.
If you don’t mind reading, here’s a more in-depth breakdown.
TS stands for Tip-Sleeve. The name comes from the connector design. These cables have only one wire transferring audio signal and a shielding that doubles as the ground. TS cables are always unbalanced, which means they should be as short as possible. They can only carry mono audio signals.
TS cables are often called instrument cables or guitar cables because they are used to connect guitars to guitar amps. They are also used to connect other instruments (pedals, drum machines, etc.) to audio interfaces, mixers, amps, etc.
The most common size for TS connectors is ¼-inch (6.35mm), but they also exist in 3.5mm form.
Cables with TS connectors are sometimes used as interconnects between PA speakers and amplifiers. Basically, they are used as speaker cables, but they shouldn’t be mistaken for traditional speaker cables with banana plugs or guitar cables.
Speaker cables with TS connectors have a different cable geometry than common TS cables (instrument cables). They have thicker core wires designed to handle higher voltage and less shielding. Instrument cables have a much thinner conductor wire and more shielding.
Speaker Cables with TS Connectors VS Instrument Cables with TS Connectors
TRS stands for Tip-Ring-Sleeve and refers, again, to the construction of the cable connector. It looks very similar to the previous TS connector, but instead of one black circle on the connector, you have two. Also, inside the cable, there’s an additional conductor allowing the cable to transmit stereo signals.
TRS cable can carry balanced mono audio signals or unbalanced stereo signals. So, they can be both – balanced and unbalanced.
Balanced applications include connecting microphones to audio interfaces with TRS mic inputs (usually 6.35mm) and connecting mixers to studio monitors with balanced 6.35mm TRS inputs.
Unbalanced TRS cables are also very common and are used to connect headphones to various audio sources.
While balanced TRS cables usually come with 6.35mm connectors (although it’s not impossible to make a balanced cable with 3.5mm connectors), unbalanced TRS cables are available and equally present in both sizes – 3.5 and 6.35 mm. Also, you can easily convert 3.5mm to 6.35mm TRS connects and vice versa.
TRRS stands for Tip-Ring-Ring-Sleeve. Like in the previous two examples, the name refers to the connector design.
TRRS cables are similar to TRS cables but with one additional black band on the connector and one additional conductor/wire inside the cable.
That additional wire can be used to carry an additional mono audio signal (like a mic signal) along with a stereo signal. In this case, the TRRS cable will be unbalanced. Headphones and earbuds with in-line mics, for example, use these TRRS cables and connectors. Some smartphones also have 3.5mm TRRS connectors.
On the other hand, four conductors inside the TRRS cable (3 wires and a shielding) can be configured to carry balanced stereo signals, but without the mic signal.
TRRS connectors also exist in both sizes – 3.5mm and 6.35mm. Some audiophile headphones come with balanced TRRS cables with a 2.5mm TRRS cable connector.
|TRS||Yes||Yes||Yes (Unbalanced)||Yes (Bal.)||No|
|TRRS||Yes||Yes||Yes (Bal. w/o mic)||Yes (Bal.)||Yes|
It’s worth mentioning that there’s another type of these cables with tip-ring connectors, and it’s a balanced TRRRS (yes, that’s three Rs) with a matching 4.4mm TRRRS connector called Pentaconn. This connector was developed by NIPPON DICS, and it’s currently used by SONY and Sennheiser headphones, headphone amps, and digital audio players.
TS Vs. TRS Vs. TRRS – What’s the Difference
RCA cables are among the most common audio cable types in our homes. RCA connectors can be found in AV receivers, TVs, speaker amps, turntables, CD players, Blu-ray players, soundbars, powered speakers, and other home A/V equipment.
The design of the cable is fairly similar to the design of the TS cable – you have a wire and shielding. Due to their design, RCA cables transmit mono sound and are always unbalanced.
So, when connecting stereo equipment, you must use an RCA cable with two male plugs on one end (L and R) and two on the other end. The plugs are usually color-coded – red (right channel) and white (left channel).
If you don’t have matching connectors on both pieces of equipment you want to connect (let’s say a TV and a pair of powered speakers), you can use interconnects with RCA plugs on one end (to connect the cable to the speakers), and a TRS 3.5mm plug on the other end (to connect the cable to your TV).
When interconnecting modern A/V equipment, using more capable digital cables (HDMI or TOSLINK) is probably better than using RCA cables, especially if you are building a multi-channel home theater system.
As the name implies, speaker cables are most commonly used to connect passive speakers to power amps and A/V receivers.
In terms of cable geometry, speaker cables are different from other analog audio cables. They have a core, usually made of stranded copper wire, and a PVC jacket.
There isn’t just one type of connector used for speaker cables. There are four commonly used connector types. Five if you count bare wires.
The most common type of speaker cable connector is a banana plug. People also use flex pin plugs and spade lugs. Some speakers and AV receivers, usually cheap ones, can only accept bare speaker wire.
XLR cables are usually used for interconnecting professional audio gear and audiophile equipment. These audio cables are always balanced, allowing you to run them over long distances and get perfectly clean audio without any noise.
XLR cables are used to connect some audiophile headphones to headphone amps. They are also used to connect microphones to mic preamps and audio interfaces or to interconnect professional studio gear (mixers, studio monitors, interfaces, DI boxes, etc.).
XLR cables use circular XLR connectors with pins and locking mechanisms. The geometry of the cable determines the type of XLR connector and the number of pins. Together, they determine the type of audio signal an XLR cable can transmit.
XLR cables with 3-pin XLR connectors can only transmit balanced mono. They are usually used for microphones or for connecting studio monitors with separate L/R XLR inputs to a mixer or an audio interface.
Theoretically, 3-pin XLR cables can transmit unbalanced stereo audio, assuming you have an output device and an input device wired for unbalanced stereo via XLR. However, such devices don’t exist.
XLR cables with 5-pin XLR connectors feature four conductors (+ ground), which allows them to carry balanced stereo sound. They can be used for stereo microphones, for example. Also, they are used on some audiophile headphones.
Aside from 3-pin and 5-pin XLR connectors and matching XLR cables, you also have XLR cables with 4, 6, and even 7-pin XLR connectors. Each connector/cable type is designed for specific use.
XLR Cables Explained
Unlike other analog audio cables, SpeakON cables are almost never used in home audio setups. They are most often used to connect amplifiers to speakers in professional setups. Since they transmit audio signals that are already amplified, they don’t have to be balanced. In fact, they are usually unbalanced.
These cables use SpeakON connectors with locking mechanisms. The connectors were originally made by Neutrik and represent one of its trademarks.
SpeakON cables are designed for high-current applications and are often reinforced and very durable.
SpeakON cables usually have two conductors (they carry mono audio), but there are versions with 4 conductors (stereo audio) or 8 conductors. For each version, there’s a matching SpeakON connector (NL2, NL4, NL8).
SpeakON Connectors Explained
Digital Audio Cables
Here’s another infographic with some basic information about the most common digital audio cables.
S/PDIF stands for SONY/Philips digital interface. These cables are widely used in home audio setups for connecting different parts of the A/V system.
There are two very different versions of S/PDIF cables – optical cables with TOSLINK connectors and coaxial cables with either RCA or BNC connectors.
Optical Cables with TOSLINK Connectors
Optical cables transfer digital audio information in the form of light beams from the output device to the receiving device (e.g. from a Blu-ray player to the AV receiver).
They have easily recognizable squarish TOSLINK connectors. These connectors are often found on TVs, soundbars, Blu-ray players, stereo amps, and other home audio gear.
Digital Coaxial Cables with RCA Connectors
Digital coaxial cables are usually RG-6 coax cables with RCA or BNC connectors. At first glance, these coaxial cables with RCA connectors look the same as regular analog RCA cables. However, digital cables have much greater bandwidth and are optimized to transmit digital signals with a wider bandwidth.
Also, while analog RCA cables can only carry mono signals, digital coax cables can transmit much more than that.
Both types of S/PDIF cables can transmit uncompressed (lossless) 2-ch PCM or lossy multichannel formats up to Dolby Digital 5.1 and DTS 5.1.
While two cable types can do the same things, each has some advantages. The optical cable is less prone to EM and RF interference, which makes it a better choice for longer cable runs.
Digital coax cable provides greater bandwidth allowing for slightly better audio quality (up to 24bit/192kHz). Also, coax cables are more durable than optical cables.
USB connectors are probably the most omnipresent type of digital connectors on today’s digital devices. USB cables and connectors come in various shapes and sizes – USB-A, USB-B, USB-C, mini, micro, etc. They are present in both – consumer and professional audio gear.
USB cables will allow you to connect your computer to your audio interface or mixer. In some cases, a single USB cable can replace multiple other audio cables, including MIDI cables.
You have certainly noticed that new smartphones don’t have a standard 3.5mm headphone jack (3.5mm TRRS connector). Instead, they have USB-C ports that you can use to connect USB-C headphones.
The biggest problem with USB cabling, in terms of audio performance, is the lack of standardization and regulation. The production of professional audio cables follows certain standards, and that’s not the case with USB cables.
So, even if a USB cable is advertised as suitable for certain use scenarios, it may not be. That’s why you should be careful when buying USB cables for your audio setup.
HDMI cables are indispensable parts of every modern AV home or professional setup. They can transmit both audio and video signals. Due to their much greater bandwidth, they are more capable than S/PDIF cables.
HDMI cables can transmit lossless multi-channel audio. The latest versions (HDMI 2.0 and HDMI 2.1) can transmit up to 32 audio channels, enabling support for all surround sound audio formats you can think of. Older versions (from 1.0 to 1.4) support up to 8 audio channels.
HDMI cables help us reduce cable clutter in our home AV setups since they can replace multiple audio cables. The introduction of ARC (Audio Return Channel) also eliminated the need to run an additional audio cable from your TV to the receiver.
MIDI cables are probably the oldest type of digital audio cables. They feature MIDI connectors with 5 pins that resemble XLR pin connectors.
MIDI cables don’t transfer digital audio or sound. Instead, they send commands or digital messages.
Even though MIDI connectors and cables are being replaced with USB connectors and cables, they are still present on modern audio interfaces and you can use them to connect V-Drums, guitar synths, or controller keyboards.
Audio Signal Levels Explained
There are four main types of signal levels – mic level, instrument level, line level, and speaker level.
The type of audio signal level, along with a few other factors, determines the kind of cable you need to use to transmit audio. It particularly affects the choice between balanced and unbalanced cables.
A mic captures pressure changes created when someone speaks or sings into it and converts them into weak electrical impulses. Since these signals are extremely weak, a mic preamp is used to amplify the signals to a more usable level (line-level signal).
When playing guitar, the vibrations of the strings are converted into an electrical signal that is stronger than a mic-level signal, but still not usable for production. That’s why the instrument levels are boosted to line-level signals using a preamp.
Line-level signals are optimized for use with professional audio equipment such as amplifiers, mixing consoles, etc. Line-level signals can be sent from one piece of audio gear to another.
Line-level audio signals are strong enough for processing, but they are not strong enough to drive speakers. Speakers require the so-called speaker-level signals. To boost an audio signal from a line level to a speaker level, a power amp is used.
Since mic-level signals are extremely weak, mics should always be used with balanced audio cables, especially for long runs (either TRS mono or XLR cables). These cables will ensure noise elimination, which is critical for such weak signals.
Instrument-level signals (guitar, bass) are noticeably stronger than mic-level signals, and the cable runs are usually short, which is why we don’t have to use balanced cables for guitars. Instead, we can use instrument cables (TS cables).
To transfer speaker-level signals to a speaker, we can either use speaker cables (home audio setups) or SpeakON cables (high-current applications and professional setups). These cables are designed to handle the most powerful signals coming from power amplifiers.
As you have seen, the world of audio cables is huge. There are so many different types of audio cables, analog and digital, balanced and unbalanced. Each audio cable type has its unique purpose and its pros and cons.
I hope this guide helped you get a slightly better understanding of all these audio cables. If you have further questions, feel free to leave a comment below.