DJ Audio Troubleshooting Complete Guide: Fix Hum, Crackling, Freezing & Bad Sound

Four common audio problems that drive DJs crazy — and the surprisingly simple fixes that most people miss.

Every DJ has been there. You're setting up, doing a sound check, and something is wrong. Hum. Crackling. A loud noise when you plug in. Your controller freezing mid-set.

These problems look like hardware failures. They feel like hardware failures. But almost every time, the fix is something far simpler than you think — and this guide covers all of them.

Part 1: How to Fix Humming in Your Sound System — A Simple Tip Most DJs Miss

If you have humming in your sound system and you've already checked all your cables, the problem might be something far simpler than you think.

Most people's first instinct is to check their cables and make sure everything is properly connected. That is a good way to find humming caused by a bad cable. But what if you've checked all your cables and power lines and everything else and you still cannot find where the humming is coming from?

The Hidden Cause of Humming in DJ and Audio Setups

Sometimes the humming has nothing to do with your cables at all — it's about where your power adapter is physically sitting.

That can drive you crazy. The audio will play, but you will still be thinking about that humming in the background. It can be from anything, but here is a simple tip.

Here's the setup: a laptop, a plug, and the adapter part of the plug sitting right next to the mixer. Sometimes you have your setup and you try to do everything nice and clean, and you put your adapter near the controller or mixer or somewhere close to it.

But guess what — that right there is a big problem. That is what is causing the humming.

The Fix: Move Your Power Adapter Away From Your Mixer or Controller

As soon as the adapter is moved away from the mixer, the humming is gone immediately — problem solved.

So be careful how you lay your power lines and adapters running across things. Something as simple as this can be a big headache.

Hum Fix Quick Reference

Part 2: How to Fix the Loud Noise When Plugging In Your DJ Controller

This problem sounds terrifying — a loud noise when you turn up the power — but it's almost never a hardware failure.

The Problem: A Loud Noise on Startup That Looks Like a Sound Card Issue

This is a Serato settings issue — not a broken sound card — and it happens when you unplug and replug your controller without updating the audio output settings.

My main rig for DJing weddings is the DDJ-SZ2 from Pioneer. I plug into a PA deck system for my sound output.

One wedding, right before it started, I was doing my sound check. I turn up the power knob and it just gives a loud noise. I had no idea why it was making that noise.

What Happened Next: Two Controllers, Same Problem

I immediately thought my sound card was broken and went to my backup plan.

I used another controller and bought a Pioneer DJ DDJ-1000 to replace it. Because of the chip shortage, there was no sound card available — it still hasn't shipped and is on back order.

I got the 1000, continued to rock, and the same issue happened again over the weekend with the 1000. I was like, okay, am I doing something wrong? Am I blowing out these sound cards? Am I cursed?

The Real Cause: A Serato Audio Output Setting

In Serato's settings there is a feature that lets you play sound directly out of your laptop speakers.

This feature has been around for a couple of releases now. It is only available when you are actually plugged into a controller.

Here is what goes wrong. If you had laptop speakers checked in Serato, then unplugged the controller and used your laptop speakers, and then went back and plugged the controller back in — that setting stays checked.

When you plug the controller back in, your sound automatically tries to play through the controller. But Serato is still saying laptop speakers. That is what causes the loud noise.

The Fix: Uncheck Laptop Speakers in Serato Settings

It is not a sound card issue — just go into Serato settings and uncheck the laptop speakers option.

I unplugged it, plugged it back in, and the setting was still checked. Once I unchecked it, the song that was playing came through cleanly. Problem solved.

This is not a hardware fault. Before replacing your sound card or your controller, check your Serato audio output settings first.

Serato Startup Noise Fix Reference

Part 3: Balanced vs Unbalanced Cables — The Home Studio Mistake That's Killing Your Sound

Cables are one of the most common yet overlooked mistakes in DJ and home studio setups — and choosing the wrong type can ruin your sound.

There are balanced and unbalanced cables, and the difference between them is game changing.

What Are Unbalanced Cables and When Should You Use Them

Unbalanced cables are simple, often less expensive, and fine for short cable runs — but they come with a serious catch.

The best example of an unbalanced cable is your standard quarter-inch guitar cable with TS or tip-sleeve connectors. This cable has two conductors — one for the signal and one for the ground.

It's great for connecting your guitar to an amp that's close by. These are totally fine to use if you're just tracking a guitar input, so don't worry about that just yet.

But here's the real catch. Unbalanced cables are susceptible to noise interference, especially over longer distances. If you've got long cable runs in your studio, this is not ideal.

The Unbalanced Cable Mistake That Caused Hum, Crackling, and Buzzing

There's an even bigger mistake with unbalanced cables — one that caused constant hum and buzzing in a real home studio setup.

At a time when there was a lot of hum, crackling, and buzzing in the monitors, there was no clue what was wrong with them. Naturally, the assumption was that the monitors were just broken.

After bringing them back to the shop and testing them out there, the real culprit was humbled pretty quickly. Unbalanced cables were being used — specifically, a couple of extra guitar cables plugged between the monitors and the audio interface.

This was causing all sorts of low-level hum and noise in the monitors. If there is one place you don't want to be using the wrong cables, it's between your audio interface and your monitors.

Imagine spending all that money on some really nice monitors, only to introduce noise and interference with unbalanced cables. Monitors are designed to reproduce sound with precision, and they're also very sensitive for this reason.

Do not compromise that clarity. Give them the best signal you can with a balanced connection.

What Is a Balanced Cable and How Does It Cancel Noise

A balanced cable is like the unbalanced cable's bigger, smarter brother — and how it works is super cool.

The best example is your standard XLR microphone cable or a TRS cable. This cable has three conductors — two for the signal and one for the ground — and this makes all the difference.

Balanced cables carry the exact same audio on the two signal wires, except one of the signals is phase inverted. As the cable picks up noise interference along its way, that noise affects both signal wires inside in the exact same way.

When these signals reach their destination, the phase of the second signal gets flipped back. The difference between the two wires is all that's left.

Because the noise is the thing that was the same on both wires, it gets canceled out. All that remains is your clean audio signal.

When You Need Balanced Cables in Your Home Studio

Balanced cables ensure that any interference that creeps in along the way will get nullified by the time it reaches your monitors.

While balanced cables might be a tad bit more expensive than unbalanced cables, they are an investment in crystal-clear sound. If you're tracking some guitar right next to your amp or next to your studio desk, you're going to be fine with your guitar cable.

But there are some roles in your home studio setup where you're going to want to use balanced cables — and your audio will thank you.

Balanced vs Unbalanced Cable Comparison

Part 4: DDJ SX3 Freezing and Dropout Fix — Move Your Phone Away from the Controller

Not all audio problems come from cables or settings. Sometimes the source is something you carry in your pocket.

Why the DDJ SX3 Freezes and How to Fix It

The freezing and dropout problem on the DDJ SX3 has a surprisingly simple solution — your phone's Wi-Fi signal.

This isn't just a DDJ SX3 issue. A previous controller, the Numark four-track, had the exact same freezing problem.

The only solution to that is very easy: turn off your Wi-Fi from your phone.

How Your Phone Is Causing the Dropout

If your phone is beside or on top of the controller with Wi-Fi on, or a hotspot active, that signal is causing the dropouts.

If it's getting any signal from your Wi-Fi, 4G, or 5G, that's the one that's making the dropouts. It's not entirely clear why or how, but it was tested and confirmed.

The phone was placed at least a meter away — about a seat's distance from the controller — and it ran for three hours with no glitch, no dropouts, no problem.

The Exact Fix to Stop the Freezing

Take your phone away from the controller and make sure it is not beside or even near your laptop.

It should be far away — a meter or two meters away. That's it.

That's the only solution found to eliminate the dropout, the buzz, and the freezing.

If this fix doesn't work for you, leave a comment — there may be another solution worth exploring together.

Phone Interference Fix Reference

Quick Reference: Which Fix for Which Symptom

Prevention: How to Avoid These Problems Before They Happen

Once you've fixed your audio issues, here's how to stop them coming back.

1. Cable management matters for audio quality, not just tidiness Keep power cables physically separated from audio cables. Don't run them parallel to each other. Cross them at 90-degree angles if they must intersect.

2. Keep a known-good balanced cable set in your DJ bag Label a set of XLR or TRS cables as your "monitor cables" and don't borrow them for other uses. If hum appears mid-gig, you can swap them immediately.

3. Before every gig: check your audio settings Make it a habit. Open Serato (or your preferred software), go to audio settings, confirm the correct output device is selected, and laptop speakers are unchecked.

4. Phone placement is part of your sound check Make a conscious decision about where your phone goes when you start playing. On a table at least a metre away. Not on the controller. Not next to the laptop.

5. Label everything A power adapter can look identical to any other adapter. Label yours. Know which one goes with which device. If you're troubleshooting, you'll know exactly where your adapters are.

6. Invest in quality cables where it matters most Skimp on the cables for your headphones or your phone charger. Never skimp on the cables between your audio interface and your monitors, or between your controller and your mixer. Balanced, shielded, properly wired cables are worth the investment.

Summary: All Audio Fixes at a Glance