What's the point of a DJ controller with balanced outputs?

Balanced outputs on a DJ controller, such as XLR or 6.3 mm TRS jack, aren’t there to make your mix sound better. They’re there to keep interference and hum out on the way to the speakers. At home, with a short cable, you’ll barely notice the difference. On stage, you will.

XLR

In short: here’s how it works

A cable is essentially a long antenna: along the way, it picks up interference from lights, power cables and phones. With a standard output (RCA), you hear that interference as noise or hum. With a balanced output (XLR or 6.3 mm TRS jack), it gets cancelled out. At home, with a few metres of cable between your controller and your speakers, you’ll hardly notice the difference, but on stage, with longer cables, you certainly will. Note: both devices need balanced inputs/outputs, otherwise a balanced cable is pointless.

» Balanced and unbalanced connections explained
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Unbalanced 6.3 mm jack cables (TS)

What a balanced output does differently

An unbalanced cable, such as a standard phono cable, has two conductors: signal and ground. Any interference that cable picks up along the way, from dimmers, power supplies or the phone next to your controller, goes straight into the speaker along with the signal. There’s nothing to filter it out.

A balanced connection (XLR or 6.3 mm TRS jack), on the other hand, uses three conductors: two signal wires and a shield.

The receiving end of a balanced cable only looks at the difference between those two wires. Interference that lands on the cable along the way ends up almost equally on both wires and therefore cancels out. This is called common-mode rejection, and it’s the whole point of going balanced. The longer the cable, the more interference creeps in, and the bigger the benefit of removing it. With balanced cables, you can cover dozens of metres without your mix suffering from noise.

Don’t expect fuller bass or sweeter highs. The signal doesn’t get better, just cleaner. Many devices are actually unbalanced internally and only create a balanced version at the XLR output. The benefit lies purely in what doesn’t get added along the way.

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When it really makes a difference in practice

At home, with the controller a metre from your monitors, RCA is usually perfectly fine. Up to around three to five metres of cable, you’ll rarely hear a difference. Beyond that, things get interesting: speakers on stands on either side of a venue, a PA rack behind the stage, or an amplifier in a cubbyhole next to the booth. Before you know it, you’ve got ten or twenty metres of cable, often running right alongside power cables and lighting control.

There’s another reason, too. If your controller and the PA are plugged into different sockets, a small voltage difference between the grounds can show up as a hum in the speakers: the dreaded ground loop. With a balanced connection, the signal references itself rather than that ground, so such a difference is far less likely to cause problems.

Bear in mind: simply using an adapter cable from unbalanced to balanced is pointless, because both devices need to play along. XLR out of the controller into an RCA input on the amplifier with an adapter cable in between? Then the amplifier ignores one signal wire, and the whole connection is simply unbalanced. It’ll still work perfectly well, but the advantage of the balanced connection is gone.

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RCA cables

No XLR on your controller? Here’s how to solve it

XLR outputs are found on club mixers and larger controllers, such as the Pioneer DDJ-RX.

On small and budget controllers, RCA is the norm, sometimes with a 6.3 mm jack as the master output.

If the 6.3 mm jack output is TRS and balanced according to the manual, you can use a TRS-to-XLR cable to run a balanced signal to the PA.

If there’s only RCA, a DI box is the solution. It uses a transformer to turn an unbalanced signal into a balanced one.

» View all XLR-jack adapter plugs and cables
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» View all RCA cables

The Pioneer DJ OPUS-QUAD has it all: RCA on master 2, XLR on master 1 and balanced 6.3 mm jacks (in other words: TRS) on the booth outputs

XLR or 6.3 mm TRS jack: what’s the difference?

Electrically, XLR and a 6.3 mm TRS jack do exactly the same thing: three conductors, the same line level and the same noise rejection. The difference lies in the plug itself and in the equipment at the other end of the cable. So you choose between the two based on your speakers and mixer, not on sound quality.

XLR has a locking mechanism: the plug clicks into place and only comes out when you press the latch. If someone trips over a cable on stage, the connection stays put. That’s why active PA speakers and mixing desks almost always have XLR inputs. An XLR connection is also always intended to be balanced, so you don’t have to give it a second thought.

A TRS jack is slimmer, making it easier for manufacturers to fit onto a small housing. On the downside, the plug doesn’t lock. It’s also longer, so you’re more likely to damage the connector and the input if you knock into it. And always check the back of the device or the manual to see whether the jack output really is balanced, and for a balanced connection, make sure you use proper TRS cables, not TS (TS works fine in itself, but the signal won’t be balanced).