AUDIO CONNECTORS | XLR, 1/4-Inch, 3.5mm, SpeakON, RCA, & More

January 14, 2021

There are many types of connectors you’ll encounter when working in the audio production industry. It’s important to know how to identify each connector type so that you can choose the right cable in each situation.

By the end of this post, you’ll know the basic types of audio connectors and each connector’s common uses.

XLR Connectors

Let’s start with the XLR connector.

Construction

An XLR consists of three pins. Most XLR cables (sometimes called microphone cables) consist of a positive signal wire, a negative signal wire, and a shield.

Common Uses

XLR cables are most commonly used to make balanced connections between two devices.

A balanced connection is a method that helps to prevent noise from entering a signal.

XLR connectors are the standard in professional audio for line level and microphone level signals. You can learn more about the difference between microphone level and line level by reading the post I wrote about Audio Signal Levels.

You’ll find them on microphones, mixers, amplifiers, and many other types of pro audio equipment.

In some cases, XLR connectors will be used for carrying digital signals. This means that instead of an analog audio signal, a digital audio signal will be passed through the connector, such as in an AES3 connection.

¼-Inch Connectors

Now let’s talk about ¼-inch connectors.

There are a few different types of ¼-inch connectors. Each type of ¼-inch connector is capable of carrying a different type of signal based on the connections provided by the connectors on each end of the cable and the cable, itself.

The most common types of ¼-inch connectors are TS and TRS.

1/4-Inch TS Connectors

Construction

A ¼-inch TS connector consists of two sections – a tip and a sleeve. This allows for two connections between the devices being connected.

Common Uses

The most common uses of ¼-inch TS connectors are instrument cables and speaker cables.

¼-inch TS connectors can only be used for unbalanced connections.

Although these two types of cables look identical from the outside, the difference between a ¼-inch instrument cable and a ¼-inch speaker cable has to do with the cable, itself. You can learn more by reading the post I wrote on Instrument Cables vs Speaker Cables.

1/4-Inch TRS Connectors

Construction

A ¼-inch TRS connector consists of three sections – a tip, a ring, and a sleeve. This connector provides three points of connection between devices.

Common Uses

¼-inch TRS connectors are most commonly used for stereo headphones or balanced line level connections.

A TRS connector can only facilitate a single channel of balanced audio. When a TRS is used to carry a stereo signal, the connections are unbalanced. 

When you find this connector on headphones – the left and right channels are carried through the same cable using a ¼-inch TRS connector.

⅛-Inch Connectors (3.5mm)

The same principles that apply to ¼-inch connectors apply to ⅛-inch (or 3.5mm) connectors. The type of signal a 3.5mm connector can transmit is determined by the number of connections on the connector and the type of cable being used.

3.5mm TS Connectors

Construction

A 3.5mm TS connector has two sections – a tip and a sleeve.

Common Uses

3.5mm TS connectors are not very common, but you will sometimes see them attached to some consumer microphones.

3.5mm TRS Connectors

Construction

3.5mm TRS connectors have three sections – a tip, a ring, and a sleeve.

Common Uses

Although 3.5mm TRS connectors could support a balanced connection in theory, most cables with 3.5mm TRS connectors are designed for carrying unbalanced stereo audio signals.

They are very commonly used for connecting to headphone, line outputs, or auxiliary inputs on consumer equipment, such as smartphones, laptops, and portable speakers.

It’s important to understand that 3.5mm TRS connectors are usually for unbalanced stereo signals. This means that anytime you use an adapter that has a 3.5mm stereo connector, the connection will be unbalanced. 

This is the case even when using a 3.5mm to XLR adapter. Although XLR connectors are capable of balanced connections, these adapters are limited to unbalanced connections by the 3.5mm TRS connector.

3.5mm TRRS Connectors

Construction

Finally, 3.5mm TRRS connectors consist of four sections – a tip, two rings, and a sleeve.

Common Uses

3.5mm TRRS connectors are most commonly found on headsets which contain two headphones and a microphone. All three of these unbalanced signals share the same reference to ground.

The pinout of 3.5mm TRS connections varies. This means that you might need an adapter depending on if you’re connecting to a laptop, a smartphone, or a DSLR camera.

RCA Connectors

Let’s move on to RCA connectors. Although RCA connectors are usually found on consumer equipment, you may still encounter them in pro audio.

Construction

RCA connectors consist of a pin and a sleeve. This allows them to form unbalanced connections between devices.

Common Uses

RCA connectors are most commonly used to carry line level signals between consumer audio and home theater equipment. Occasionally, you will find a set of RCA connectors on an audio mixer.

If you are connecting consumer audio equipment to your professional audio equipment, or vice versa, read the post I wrote about Consumer & Professional Audio Levels to learn about the different voltage level standards for consumer and professional audio equipment.

Phoenix Connectors (Euroblock)

Another common type of connector in professional audio is a phoenix connector, or a euroblock connector.

Construction

Phoenix connectors are usually custom made for specific pieces of equipment. They usually consist of three connections – positive, negative, and ground.

Common Uses

You will usually find phoenix connectors on amplifiers, DSPs, and other audio gear for installation.

These connectors occupy a very small amount of space, making them useful for minimizing the rack space required for equipment. However, phoenix connectors are much less rugged than XLR and TRS connectors, so they are rarely used for connections that will be connected and disconnected regularly.

SpeakON Connectors

You may also encounter SpeakON connectors for connecting amplifiers to speakers. There are three common types of SpeakON connectors – NL2, NL4, and NL8.

Construction

NL2 connectors have two pins, NL4 connectors have four pins, and NL8 connectors have eight pins.

Common Uses

SpeakON connectors are used for connecting professional amplifiers and speakers.

A speaker circuit requires two wires – positive and negative. The number of pin sets a SpeakON connector has determines how many speaker circuits it can support.

An NL2 can support one speaker circuit, an NL4 can support two speaker circuits, and an NL8 can support four speaker circuits.

These connectors are much safer than ¼-inch speaker connectors for a couple of reasons.

For one, they lock in place with a spring loaded release button. This prevents them from being disconnected accidentally.

They are also safer because the connection points are located within a plastic housing. This makes it more difficult to shock yourself by accidentally touching the connections. This is a much bigger concern when dealing with speaker level signals than dealing with line level signals.

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