You are currently viewing Why Do Microphones Use XLR?

Why Do Microphones Use XLR?

XLR is like the industry standard when it comes to cables for microphones. But why do people use XLR as oppose to other connector types? Here’s a short and concise answer to that question:

Microphones use XLR because:

  • A balanced audio signal is used to isolate noise. That means if there is electronic interference during the transmission, the noise can be removed, resulting in clean audio.
  • The ground pin comes in contact first. We avoid sending static shock into the microphone potentially damaging it.
  • There is no short circuit when connecting.
  • They can send 48V phantom power.
  • Only the exact same connector can be plugged in.
  • The locking latch mechanism locks it in place.
  • They’re durable and safe.

Let’s take a deeper look into why microphones use the XLR connector!

What is an XLR connector?

The name XLR comes from:

  • “X”: Original name of the connector is Cannon X connector.
  • “L”: Addition of a Locking latch mechanism.
  • “R”: Addition of resilient rubber/neoprene insulation from the female contacts.

As you can see, the XLR connector has evolved quite a bit since it was first invented.

The XLR is a connector type commonly used in the audio industry for microphones. Note that in audio, the most common is the 3-pin version (XLR3). There are other XLR versions with 4, 5, 6, and 7 pins. Rest assured, although they may look similar, due to the difference in the number of pins, accidentally connecting different versions is not possible.

Why do microphones use XLR?

A balanced audio signal is used to isolate noise

The biggest advantage of using an XLR connector for microphones is that they carry a balanced audio signal. A balanced signal can cancel out the noise introduced due to interference, thus resulting in a clean audio signal. For short distances, you may not notice a lot of noise when using an unbalanced cable. However, the longer the distance, the bigger the problem it becomes.

On an XLR connector, there are 3 pins:

  1. Ground/shield wire.
  2. Positive/hot wire.
  3. Negative/cold wire.

By sending the audio signal through the positive/hot wire, and having an exact copy but its polarity reversed sent through the negative/cold wire, at the end of the transmission if we sum the difference between the two signals, we can cancel out any noise introduced during the transmission.

This is an important feature as microphone cables tend to be quite long, and during the transmission, there is usually electronic interference from other electronic devices. So that is the main reason why we usually use XLR connection for microphones.

The ground pin comes in contact first

Another advantage of using the XLR connector for microphones is a safety issue.

If you look at the three pins on a male XLR connector, you may notice that one of the pins is slightly longer than the other two. That pin is for the ground/shield wire. By making it the longest pin, it ensures that the ground always comes into contact first. By doing so, we avoid sending a large static shock down the wires, potentially damaging the microphone.

Other connectors like the phone connector (TS and TRS) does not connect to the ground first, due to its linear arrangement of connection. So if we were to use a TRS connector for a sensitive microphone, there is a high chance we may damage it due to static shock.

There is no short circuit when connecting

Another thing to note that all three pins are separated. When we connect it to the microphone, there is no chance of connecting the wrong wires. Unlike a phone connector (TS or TRS) which shorts when we connect it due to the design being in a linear fashion. Microphones are very sensitive devices, so by using an XLR connection we avoid any short circuit during connecting and disconnecting the devices.

If we’re to send power down the wires, and we short circuit it, there is a high chance of our microphone being damaged.

They can send 48V phantom power

Condenser microphones are one of the microphone types which require power to operate. We usually use a 48V phantom power to power the microphone. By using an XLR connector, we can send the power through pins 2 and 3. And because none of the pins will be in contact with another, even when we’re plugging it in, there is no risk of short-circuiting due to sending power down the wrong wire.

We mentioned in the last section that a phone connector (TS or TRS) will short circuit when we’re plugging it in, and damage can be done if we’re sending power. This is another main reason why XLR connector is used for microphones, because many microphones need 48V phantom power, and we cannot risk short circuiting the microphone.

Only the exact same connector can be plugged in

If you’ve read the section near the top of this article explaining the basics of XLR, you know there are more than one type of XLR connector. We talk about the 3-pin (XLR3), but there are XLR connectors with 4, 5, 6 and 7 pins. However, the great thing about the XLR connector is, only the connectors with the exact same number of pins can be connected.

This is a huge advantage when working in a practical setting, when many cables are used. Unlike many other connector types, you cannot connect the wrong plugs together. This is not only time-saving, but can potentially save devices from being damaged due to sending the wrong power or signal down the wires.

The locking latch mechanism locks it in place

XLR connector is one of few types of connectors featuring a locking mechanism. This makes is favorable when choosing connector types for working with sensitive and expensive equipment, say, microphones.

By having a locking latch mechanism, even if we accidentally knock or pull the cables, they won’t come off easily. Note that the mechanism is usually made with metal. This makes it suitable for use in any kind of setting including studios, on stage, backstage, etc. Even if the singer accidentally steps on the cable and pull the microphone, the connection will usually stay intact.

They’re durable and safe

We mentioned the locking latch mechanism in the above section, but the overall quality and design of an XLR connector makes it extremely durable and safe. The size, the materials used, and the way wires are insulated and connected to the pins are all brilliant designs.

Usually when you rip the cable, you’re more likely to disconnect the cables, than to damage the actual connector.

This is a huge contrast when comparing with the phone connector (TS and TRS), which usually rips at the connector, leaving part of the connector inside the other device.

Leave a Reply