How to Use an XLR Generator (Pink Noise)

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I’ve got with me here a little plug called an XLR pink noise generator made by Optogate. It also serves another function, which is that you can test the power. That’s the 48 volts going down powered microphone leads or DI (Direct Input) leads. Not to be confused with a Tone Generator which is for a different use.

Using an XLR Pink Noise Generator

First of all, let’s take a look at the pink noise generator. Well I think what I will do is plug in to this little mixer with the standard XLR lead. On the end of that lead where the microphone would normally go, that’s where I’m going to plug in the pink noise generator. Make sure you do this of course, with the volume down on the desk. Next,  turn on the 48V on the desk which will provide IC (Integrated Circuit), the chip inside the plug for its power.

When the red light comes on at the end, it’s generating pink noise. If I turn the channel up, then you’ll hear what can be described as a hissing sound.

XLR Mic Troubleshooting

What’s it all for, you might ask? Well, if you’ve got constant noise, you can check the signal flow. So once you know the microphone or DI-Box has power, you have a visual representation, something you can look at all the way through the system. In this case you can also hear it, let’s give a couple of scenarios.

When at your workstation, no microphone is seen in the recording side of things. Put the pink noise generator on and you can then follow the signal all the way through your gear. It might also be sent off to a reverb unit or an echo device, or some piece of outboard gear.

Using Pink Noise with a PA System

If you’re on a P.A. system, then you’d use this to check that the subs are working for mid range and high frequencies. It also checks the monitors to make sure that the monitor sends are going to the correct speakers on stage. If a microphone at the back of the stage went down, say, an overhead mic, take the plug and plug it in. Place the microphone, look at the end of it and see if the lights have lit up.

If they haven’t, you will need to get some 48V to it, especially if it starts to flash. This is another feature of it so take note of the flashes as described below.

  • Two flashes means that PIN/Cable two has gone down.
  • Three flashes means that the PIN/Cable three’s gone down. And in that scenario, you’ve simply change the mic cable.


Overall, this is a very neat piece of kit, never amiss in a tool box. Always useful for fault finding. It’s small. It works well. It’s reliable. Price wise, they’re are around the 40 pound mark.

Thank you to Terry Finn from Affinity Audio who is also selling the device for £36.00.

Physical dimensions: 74mm Length x 19mm diameter
Case construction: Neutric XLR Plug
Output signal: Pink noise
Amplitude: About 100 mV peak – peak
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