Audio Connectors and Cable Types: The Ultimate Guide

While everyday music listeners have already switched to wireless technology, audio connectors and cables still play an essential role for audiophiles, professionals, and home entertainment systems.

Learn everything about audio cables and connectors:

• In how many ways you can use them

• Which are the best for a given application

• Can they affect the sound

Types of Audio Cables

We know two different kinds of cables: analog and digital.

• Analog cables transfer audio signals by fluctuating voltage in positive-negative cycles. Then speakers turn the signal into sound waves that vary in frequency and amplitude (or loudness).

• Digital cables send audio information as a stream of 1’s and 0’s that a digital-to-analog converter (DAC) has to turn into an analog audio signal.

Analog cables

You might see at least 3 types of analog audio cables commonly used in home or professional applications.

TRS cables

TRS (Tip, Ring, Sleeve) are the most common type of cable with 6.35mm (1/4 inch) or 3.5mm (1/8 inch) connectors.

There are different versions of this cable: TS, TRS, TRRS, and TRRRS. TS supports mono unbalanced, TRS either stereo unbalanced or mono balanced, and TRRS stereo balanced signal. More on that below or in our in-depth article on headphone jacks and plugs.

Cable limitations:

• Cables over 3 meters will pick up external noise if not adequately shielded (unless they use a balanced connection).

TRRS plug has a dedicated conductor for a microphone. But the actual position is determined by the standard it uses. It’s either:

• OMTP (Open Mobile Terminal Platform)
• Or CTIA (Cellular Telecommunications and Internet Association)

XLR cables

XLR is another widely spread type of cable usually used in studios. They can carry mono-balanced or stereo-unbalanced signals (or stereo balanced if they have 4 or 5 pins).

With more pins, you have more possibilities, like creating an unbalanced stereo and adding an unbalanced microphone signal, etc.

Cable limitations:

• Cables over 3 meters, if not adequately shielded, pick up external noise (if you use them for an unbalanced connection).

RCA cables

RCA is the last of the most common types of cables. However, it is used less and less.

Each connector sends a mono-unbalanced signal from one channel. Together, they form an unbalanced stereo audio connection.

Cable limitations:

• Cables over 3 meters, if not adequately shielded, pick up external noise.

Digital cables

You might be familiar with at least 3 types of digital audio cables commonly used for home entertainment.

HDMI cables

HDMI cables are mostly known for transferring a video signal. However, to make life easier for consumers, they made HDMI also transfer audio.

You recognize the HDMI cable by its trapezoid-shaped connector with numerous tiny pins inside. It can carry high-definition audio (up to the 24-bit depth and 192kHz sample rate).

Furthermore, it handles surround sound multichannel signals (up to 32 audio channels) in formats like Dolby Atmos and DTS: X.

Cable limitations:

• Cables longer than 5 meters must be labeled “High-Speed”.
• Since all HDMI connectors look the same, it is hard to distinguish between HDMI versions.

HDMI is typically used for:

• Connecting source to a TV
• Connecting source to an Audio/Video receiver

Optical cables

Optical cables use optical fibers and light to transmit digital audio signals. You recognize it by its small rectangular connector with a fiber pimple sticking out (TOSLINK).

While older analog connections like RCA and 3.5mm jacks are going away, you can still see optical inputs on the back of your new TV, AV receivers, PC motherboards, and so on.

Developed in 1983 by Toshiba, TOSLINK is meant to increase audio quality over analog alternatives. While still practical to connect older audio gear to a receiver, HDMI outcompeted them.

Optical cables transfer 7.1 surround sound formats like Dolby Digital or DTS Surround, up to 20-bit depth, and a 48kHz sample rate. However, they can’t handle Dolby Atmos or DTS: X.

Cable limitations:

• It should be less than 5 meters long.

Optical or TOSLINK is typically used for:

• Connecting (older) source to an AV receiver
• Connecting source to active speakers

Coaxial cables

Coaxial cables look very similar to the RCA cables mentioned above, as they use identical connectors. The female coaxial connector is often black or orange in color (More on male/female connectors down below).

That is another older type of digital audio connection that offers limited possibilities. It supports audio formats up to 5.1 surround, like Dolby Digital and DTS Digital.

Cable limitations:

• Doesn’t have enough bandwidth for 7.1 surround sound.

Coaxial is typically used for:

• Connecting (older) source to an AV receiver
• Connecting source to active speakers

What is the difference between balanced and unbalanced connection?

The difference between balanced and unbalanced cables is that the first can cancel out the noise picked up by the cable itself.

Remember when you could hear loud beeping through your speakers when someone called you on a smartphone? The reason is that the cable picked up the outside interference.

You can avoid these types of radiation or electromagnetic interference by properly shielding the cable or using a balanced connection.

How does a balanced connection work?

Every cable has a signal and a ground wire. An unbalanced one only has one signal wire, whereas a balanced one has two.

1. The transmitting device sends the same signal through both wires, but one has its phase inverted. Signals in the cable don’t meet, so they don’t cancel out.
2. Both wires are twisted through the cable so that any external noise is picked up equally by both wires.
3. On the receiving side, the inverted signal’s phase gets inverted again, but now the phase of the picked-up noise is inverted.
4. The two opposite noises cancel each other out, with only a clean signal remaining.

Types of Audio Connectors

Audio connectors are used to connect the audio cable to another audio device. Since cables support different types of connections (analog, digital, balanced, and unbalanced), they come in different shapes.

We have already covered some of the connector designs in relation to cable and connection type. Now, let’s dive deeper into connectors themselves.

Male and female connectors

Every connector had a male and female side, which are inverted versions of each other.

• A male connector sticks out or has pins, whereas a female one has a hole(s).
• Male connectors are also called plugs, whereas female connectors are called jacks or sockets.

Note that this has nothing to do with inputs or outputs, as male or female connectors can be both.

Straight and right-angle connectors

Connectors can come in various angles to simplify the setup process or protect the plug and the jack from damage.

Obviously, the connector stays the same; only the angle at which you insert it is different.

• Straight connectors are the most common. Sometimes called “I-shaped”, they’re a standard angle for all sorts of connections.

• L-shaped connectors take a 90° turn and are a great solution when you don’t have enough space behind your AV receiver and you want to push it right against the wall. They’re also used to plug in guitars or portable amps so that you can wire the cable more elegantly. However, due to the shape, it doesn’t unplug as quickly if you tuck the cable, which could damage the connector.

• 45° angled connectors aren’t that common, but you can find them in some wired headphones. They represent a middle ground between I and L shape, but they can still unplug relatively quickly if you accidentally tuck the connector.

Locking connectors

Locking connectors use locks to secure themselves in place so you know they’re plugged correctly and don’t accidentally unplug.

However, out of the need to make connectors more user-friendly, they’re easily swappable and unplug if tripped on. So, most connectors lack a locking mechanism due to user-friendliness.

The most popular locking connectors are XLR.

Common Connectors in Headphones

3.5mm connectors

3.5mm (or 1/8 inch) is the most common connector size found to connect headphones to entertainment devices like cell phones and computers.

It usually uses TS cable for mono signal (unbalanced mono) or TRS for stereo signal (balanced mono or unbalanced stereo).

TS configuration is typically used for:

• Instruments
• Connecting microphone
• Connecting speakers (that support LINE connection)

TRS configuration is generally used for:

• Wired headphones
• Connecting a source to an analog amplifier

How do you know the type of cable?

You recognize the type of cable by looking at a connector (plug conductors) and seeing how many black stripes are under the tip. If it’s one, it’s TS, and if there are two, it’s TRS. 

Connectors are also called 2-pole connectors on a TS cable, 3-pole on a TRS cable, and so on.

6.35mm connectors

Another widely popular headphones connector is 6.35mm (or 1/4 inch). It’s primarily used for more professional audio applications, as most of the studio equipment uses this type of plug.

Like the 3.5mm, the 6.35mm also come in TS and TRS configurations, and their use cases remain the same.

2.5mm connectors

These are much rarer types of connectors, primarily found in audiophile products. Although, some Bluetooth headphones use it for wired connection, like Bose Noise Cancelling Headphones 700, for example.

Unlike Bose’s version, 2.5mm connectors usually support a balanced stereo connection, so they use a TRRS cable. That means that the jack has 3 black stripes (4-pole connector).

Don’t confuse these cables with the 3.5mm 4-pole jacks you might see on some headphones. In that case, the additional ring takes care of a microphone signal.

Connectors limitations:

• Expensive, as they are a niche product for audiophiles.

TRRS is generally used for:

• Connecting headphones to a dedicated amplifier

4.4mm connectors

4.4mm is another niche and rare type of connector that also comes in TRRS configuration. It supports a balanced stereo connection.

Since they use the same configuration, with different size, they share the same characteristics as a 2.5mm headphone jack.

How to connect wired headphones to a phone without a jack socket?

The only way to connect wired headphones to a phone without a jack socket is to use an audio adapter or an audio dongle.

• With Apple devices, it’s pretty straightforward, as all adapters use a Lightning port (except for Macs and iPad Pros that use USB-C).

• On the other hand, other smartphones use USB-C audio adapters. Most of them are digital, but some use analog ones (mainly brands like Huawei; Google Pixel once used analog dongles, but thankfully not anymore).

Common Connectors in Audio Systems

Audio systems include everything from stereo amplifiers and AV receivers to power your living room speakers, to DACs and headphone amplifiers to drive your power-hungry headphones.

Here are all types of connectors you might encounter in such systems.

6.35mm and 3.5mm jacks

Quarter-inch and 1/8-inch connectors are also used for transferring analog audio from one device to the other. In most cases, from a computer or a phone into an amplifier.

6.35mm and 3.5mm jacks are typically used for:

• Transferring analog audio from a source to the amp
• Connecting speakers (that support LINE connection)

XLR connectors

XLR connectors are popular in professional audio equipment primarily because they offer a balanced mono connection and are very durable.

You recognize it by its big, circular connector with 3 pins inside (although even 5-pin XLR connectors exist).

XLR is generally used for:

• Connecting microphones
• Connecting instruments
• Sending a signal to amplifiers, mixers

RCA connectors

RCA connectors range from analog to digital (coaxial mentioned above).

You recognize the analog version by its small circular connector with one pin sticking out. Typically, you have 2 connectors, one red and the other white. The yellow connector is for a video signal.

Most commonly, you see RCA audio connection between a TV, CD/DVD/Blu-Ray players, and on receiving devices, like stereo or AV receivers.

However, the RCA connector is slowly getting replaced by digital solutions like HDMI.

RCA is generally used for:

• Connecting source devices to an amplifier

SpeakON connectors

The SpeakON connectors are used for sending the audio signal and powering the speakers simultaneously. They’re suited for high-current audio applications (up to 40 amperes).

In a way, they’re somewhat similar to the XLR, but the latter is only usable for low-current applications.

Just like the XLR connectors, the SpeakON connectors have a locking system, just that you have to twist it instead of just pushing it.

A benefit of SpeakON connectors is that they offer better sound quality and are easily serviceable on the spot if you have to quickly repair a damaged connector.

Are Headphone Audio Connectors Different Than for Speakers?

First, let’s talk about connectors that receive a signal before sending it toward your headphones or speakers.

Headphones

Most headphones use standard audio connector types like:

• 3.5mm – analog
• 6.35mm – analog
• USB – digital

You can find gaming headsets with RGB lighting using a USB cables because they require extra power to power the effects.

Speakers

There are active and passive speakers, the difference is that active ones have a built-in amplifier, whereas passive ones require external amplification.

Connectors mainly used for active speakers are:

• RCA – analog
• 3.5mm – analog
• Optical – digital
• Coaxial – digital (if the speaker also has a built-in DAC).

On the other hand, passive speakers rely on external amps. The latter normally work on an analog connections:

• RCA
• 3.5mm

Unless they are AV receivers, which can also use numerous digital connectors like Optical, Coaxial, and HDMI.

Now let’s discuss connectors that are directly attached to headphones and speakers.

Headphones

Many headphones use a fixed connection, so you can’t unplug the wires out of the ear cup without damaging it.

If headphones or in-ear monitors (IEM) have the option to unplug the cable, you might see a flood of different standardized or proprietary connectors.

• 3.5mm

• 2.5mm

• Mini-XLR

• 2-pin (the one for IEMs and headphones isn’t the same)

• MMCX (for IEMs)

Speakers

The speakers are usually connected to an amplifier with a simple set of 2 wires (or 4, if speakers support bi-wiring).

Most consumer speakers have a latch or a screw that secures an exposed wire in place.

More high-end speakers utilize simpler plug-in connectors like the “banana” plug. Or, in the case of professional applications, a SpeakON connector.

Do premium headphone cables make a difference?

Premium headphone cables don’t make a difference in sound quality over the original stock cable. No measurement has proven that so far.

There’s a hot debate among audiophiles about whether expensive headphones or speaker cables can make an audible difference. However, there’s no scientific proof of that.

Cable upgrades can cost an absurd amount of money, up to $800. If you want to improve the sound quality of your headphones or speakers noticeably, pick a better amplifier instead.

How to Choose the Right Audio Cable and Connector

By now, you know there are many different cables and connectors you can choose for your headphones or speaker system.

Let’s discuss some benefits and limitations regarding popular connections.

6.35mm and 3.5mm connection

In most cases, these types of connectors come attached to TRS cables.

XLR connection

XLR cables are rarely used for driving headphones, but if they do, they usually come with a 4-pin connector, which ensures a balanced stereo signal. Normally, they’re a part of expensive cable upgrades.

2.5mm and 4.4mm connection

These types of connectors are less utilized for headphones, but they’re popular among hardcore audiophiles since they offer a balanced connection.

Common Problems with Audio Cables and Connectors

Nothing lasts forever, and even cables and connectors eventually stop working for various reasons.

Cable damage

Cables are nicely protected under their rubbery shield. However, you have to remember that under that shield, there are threads of tiny, fragile wires that can only take so much stress.

Cable damage can occur due to the following:

• Bending the cable too much or continuous bending.
• Electrical overload that heats the wires and damages them.
• Degradation of the materials inside the cable.
• Running over the cable with a chair.
• Bitten cable due to rodent attack.

Connector damage

Connectors are even more susceptible to damage due to user misuse.

Connectors are most commonly damaged due to the following:

• The excessive strain put on the connector, causing it to break.
• Wear over extended periods of use (like a 3.5mm jack rubbing against pins, which can scratch a groove into the jack).
• Electrical overload that fries the surface of the connector, making it non-conductive.

Signal interference

As mentioned under the balanced/unbalanced title above, external signals and other electromagnetic interference (EMI) can creep into the cable and become audible noise.

While today, cables have better shielding than 15 years ago, when they were able to pick up a random radio station, they can still pick up EMI.

Signal interference occurs when:

• The cable is too close to another electrical device that operates under strong current (even computers can be a source of EMI).

How to maintain and troubleshoot audio cables and connectors

Like anything in life, if you treat it gently and correctly, you extend its longevity. The same goes for cables and connectors.

Cables

• Don’t pull on the cable or constantly bend it to avoid snapping the wires inside.
• Don’t tangle the cable or leave it on the floor beneath your feet. When not in use, tie the cable in a loop (that’s not too small) and keep it on the desk or somewhere you can run it over with a chair or away from the reach of your pet.

Connectors

• Don’t bend the cable right at the connectors, even if it has a strain relief. Ensure minimal bending and pulling on the connector.
• Don’t throw connectors on the floor as you might break or bend them in a way they would plug in anymore.
• Clean connectors that could collect dusk and gunk (like AUX ports).

Troubleshooting

If your cable suddenly doesn’t transmit audio anymore, here’s how to troubleshoot:

• Replug the connector or try plugging it into something else to see if it works.
• Inspect both male and female connectors for debris that prevents the connector from fully sitting in.
• Try a different cable.

You can take the connector apart and rewire a new connector. However, that requires knowledge of how to wire a connector and how to solder, and the result might not be as functional as buying a new cable.

Frequently Asked Questions (FAQ)

Read more:

• Headphone drivers explained

Conclusion

Even though almost everything goes wireless, audio cables remain an essential part of home entertainment, high-end audio, and audio recording.

Hopefully, you learned the differences between different cable and connector types, so you’ll know how your audio system works and how to choose a better system in the future.