Properly Connecting Speakers to DDJ-400/FLX4 (2024)

Speakers Not Working on DDJ-400? Connect & Fix (13 Issues)
So you have a DDJ-400/FLX4, and you thought that you had everything set up. Songs are cued and playing in Rekordbox, but… there is no sound output.

Whether you’re new to DJing or you’ve been mixing for a while, connecting DDJ-400/FLX4 to speakers and fixing issues with speakers can be a bit tricky.

Referring to the manual/diagram to ensure you have things hooked up correctly sometimes isn’t enough.

In this article, I’ll explain how to connect DDJ-400/FLX4 to active and passive speakers, and then I’ll cover all the problems you may run into, including.

Let’s dive right in.

Preliminary Checks When Speakers Are Not Working on DDJ-400/FLX4

These are the preliminary checks you need to do:

  1. Make sure the output is not going through your laptop. A button in the upper right-hand corner of the Rekordbox main page looks like a computer with a speaker.
  2. Go to Rekordbox preferences, look for an audio output device and choose DDJ-400/FLX4.
  3. When you choose “DDJ-400 WASAPI” as your Audio Source, there is also a checkbox below which states, “Output audio from the computer’s built-in speakers and your DJ equipment (PC MASTER OUT).”
  4. Under “Output Channels,” you’ll see an option for Master Output. Make sure you are choosing whatever speakers you want to apply (e.g.: “DDJ-400 WASAPI: MASTER + Speakers (Realtek High Definition Audio)”).
  5. Make sure you turn the trim and volume sliders up.
  6. If only one channel is playing audio, ensure the Channel Fader (below the sliders) is not pushed to one side.
  7. Ensure Trim and Volume sliders are both turned up.
  8. Make sure you have the gain knob on the controller turned up.
  9. Make sure your speakers work with other audio devices.

Connecting DDJ-400/FLX4 to Active/Powered Speakers

The most common type of speaker people use when mixing on a DDJ-400 is an active speaker. These types of speakers combine speakers with an amplifier, so we don’t need separate pieces of equipment to project the sound.

There are three ways to connect your controller to powered (active) speakers:

  • Connect speakers directly to your computer/laptop
  • Connect them to your DDJ-400/FLX4
  • Connect them to Rekordbox via an audio interface (not common)

Keep in mind that DDJ-400/FLX4 can work without drivers. You don’t need to install additional driver software. Windows/Mac OS regular audio driver is going to be automatically installed when your controller is connected to your Mac/PC via a USB cable.

If you recently bought a pair of powered speakers (like Mackie thump 12a), you might be confused about connecting them, or there will be no sound.

You might make a mistake and have both cables connected to the mix-out port instead of a channel input, like this:

sound issues on ddj-400

You’re going to want an RCA male XLR connector. I’m not suggesting you buy exactly this cable, just showing what you need.

So then you would connect that wire to channel 1 of the first speaker and channel 1 to the second speaker and then connect it to the RCA ports.

Connect RCA from Master into the Channel 1 or Channel 2 inputs – Mix Out is an output to pass the signal to another speaker.

That’s it.


How to connect multiple active speakers?

Let’s take four active speakers, for example.

Having two RCA splitters so that you have four outputs and then putting your XLR to RCA cables in those outputs is the easiest way, I believe. However, I’d watch out for splitters as they add unwanted noises into the system at high volumes due to a host of grounding problems.

It would probably be helpful to get some kind of mixer board instead, which also allows much more freedom in volume control between the four speakers. That kind of device will be capable of preventing noise.

With a simple splitter, you will lose signal. Find out if you can go from your RCA connection on the mixer to the first speaker’s RCA connection and then link the first speaker with the second one with XLR.

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You can also buy a second-hand receiver and connect the four speakers to the receiver. Some second-hand older receivers will only set you back 50 bucks or so, which should work perfectly!

Connecting DDJ-400/FLX4 to Passive Speakers

If you have passive (unpowered) speakers, they’ll demand an amplifier to function, so that includes a couple of extra steps to set up. Understanding how to connect your audio interface to passive speakers is just as essential as running powered speakers.

DDJ-400 and FLX4 have RCA outputs, and those need to go to an amplifier which needs to go to the speakers (which have both 1/4″ and speakON inputs). 

You want an external amplifier to ensure your sound signal from your DDJ-400 is loud enough to use speakers properly. RCA from DDJ to a Line/AUX RCA input on the amp. Standard speaker wire out of the amp (e.g., this one on Amazon) to the speakers.

DDJ-400 L/R Via RCA (may need to adapt to TS or use a DI box like the ProAV2 > Qx1202 > TRS to Active Speaker from L/R of the controller to active speaker > Output of active speaker into the input of sub.

The input of one device will ALWAYS connect to the output of another device. You’ll be able to figure out how everything connects by reading documentation and ensuring the signal goes from Output to Input to Output to Input, etc.

Even if you choose an amp with XLR inputs only, you can just use an RCA to XLR cable. It’s all line-level signals, but your input volume will be about half that of XLR.

A mixer would also be nice. Interconnecting the mixer and amp with XLR would increase volume and decrease noise. Keeping the RCA cord short will help decrease potential noise too.

Why Cable That Comes With DDJ-400 Can Be a Problem?

If you suddenly notice that the volume is turned up high, and there’s nasty static sound coming out of your speakers, don’t worry. Usually, the problem is the cable that comes with the DDJ-400, which doesn’t have a ferrite coating. 

If you turn down the master volume on the DDJ-400, the sound will disappear, which indicates that the issue is not with the speaker.

The static noise arises from your laptop and is usually caused by an HDMI output (I saw this scenario many times on stage).

Once you switch it with a decent cable (like Wireworld Chroma cable), you’re good to go. You don’t have to pay too much, just get something like that.

Connecting DDJ-400 to Monitors With Only XLR Input

If you have a DDJ-400 and a pair of studio monitors with only an XLR input to the back, you might wonder how to connect both of them to your controller, is an audio interface completely required, and if so, does it matter which one you get? 

Also, is there a difference in quality if I use RCA to XLR vs. RCA to 3.5mm Plug to XLR or double RCA to double XLR? 

I dealt with the same thing when I bought my Krk Rokit 8 G4s. You need XLR cables with male RCA plugs at the other end.

You can also go TRS to RCA. For me, the G4’s used a combo plug, so either TRS or XLR fitted into the same plug. 

Something like this (Amazon link) would be the most economical solution, but then you still have to supply RCAs.

Alternatively, you can get something like this. Just ensure you don’t buy a stereo TRS cable that goes from a single 1/4 to a pair of RCAs.

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Connecting DDJ-400 to Audio Interface

Not so long ago, I bought a pair of speakers and a Focusrite Scarlett 2i2 audio interface, and I haven’t had any problems with it. Below, I’ll explain how to connect DDJ-400 to the audio interface and possible issues and how to solve them.

  • Connect DDJ-400 to the audio interface with an RCA to 1/4 Jack cable
  • Spent a moment trying to get the interface to recognize the DDJ400
  • In the audio preferences, select the DDJ400 as the output for the sound

The only distinction between the Mac and Windows is that on the Macbook, the “Output audio from the computer’s built-in speakers and your DJ equipment” setting is enabled.


Problems with Windows PC

On Windows PC, sometimes DDJ-400 works well for a few seconds (the sound is heard in the speakers and also in the headphones), but the music starts to crash, you hear strange sounds, and the Audio stops at times.

What to do?

Connect the audio interface to Rekordbox as Asio. That will only allow one application to access it, so you either get Rekordbox or Windows sound, not both. You will need to connect as a Windows Audio device.

Also, check that Windows hasn’t set the DDJ 400 as the default audio device. You also won’t be able to use the headphone output on the DDJ if you use the audio interface. Better to set the DDJ as the output and then choose the additional output as the audio interface, so Master goes to both.

And how do you select additional output?

  • Go to Audio and tick the box “output audio from computers built-in speakers”
  • Audio->Output->Output Channels->Master Output
  • Select “DDJ-400:Master + Focusrite USB Audio”

If you don’t need to use an audio interface, don’t. Duplicating the Audio is a last-resort workaround in Recordbox that you should not depend on, and, normally, there’s a latency difference between different soundcards.

Simply connect the DDJ-400, which has its own soundcard, directly to your amplifier or powered speakers and your headphones, don’t connect it to another soundcard. You can still use the DDJ-400 soundcard outside of Rekordbox as the system playback device if you would want to.

Remember, using an audio interface, you’ll be lowering your sound quality by going digital (DDJ-400) to analog (DDJ-400 RCA output) and back to digital again (audio interface).

Ideally, you want to retain your signal chain all digital until just before your speakers.

Low Volume Problem – What to Do?

Sometimes when speakers are connected to the controller, they don’t go nearly as loud as they could, even with the trim cranked all the way. Why does DDJ-400 appear to be capping the volume?

I’ve seen many people asking questions like this online but never saw someone giving a solution. 

It’s because of Rekordbox’s headroom settings. It’s -9db, so if you have trim at 12, you’ll be that much quieter than the same setting if you were just playing your normal music.

  • Ensure the meters on Rekordbox as well as the meters on the controller drop at a healthy “barely ever touching red” level with the trim knobs 
  • Head into your Rekordbox settings. Beneath controller>Mixer, there should be an output gain reduction setting. It’s set to -9 dB by default. Change to 0 dB

If you hear clipping and it’s under red, the issue might be at a different stage in your setup. Like maybe you’re pushing the speakers too hard, and it only became obvious when your DDJ didn’t have the -9db headroom.

I had a look at the few speaker manuals, and there seem to be somewhat strange input level markings on these monitors that might be confusing: 12 o’clock is labeled +4db, and 5 o’clock labeled -10db, but these values seem to represent the manufacturer recommended settings when connecting a balanced input (+4db) or an unbalanced input (-10db).

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Also, try this:

  • Since you’re running an unbalanced input (RCA to TS 1/4″), check that the input control on the back of both monitors is turned all the way to the -10db mark (5 o’clock) and your room control and high trim switch both set to 0 dB.
  • Before you play music, turn your DDJ-400 master volume all the way down, start your favorite track playing with channel meters in the green/amber, channel faders up, and slowly bring up your master.
  • Check the “Trim” knobs (the grey ones above the EQ) that work as a volume knob for each channel. Be careful with going too loud though, check the colored bars that jump with the music between the EQs and ensure you have no red bars.
  • Check the master level knob on the right (the one that sits all alone). The right side of it has a thicker line. Don’t go too deep into that area unless you need to.

Last but not least, the DDJ-400 sometimes feels like it limits your speakers a little, so make sure you’re not convinced that your having low volume when in fact, the problem is the weak audio interface built into your controller.

Sound Issues With DDJ-400 – Hissing, Static Noise, Buzzing

It can happen that as soon as you connect the controller, a loud, hissing, high-pitched sound mixed with static noise comes out of the speakers. 

Its volume cannot even be controlled, and you have to turn them off. 

You’re most probably dealing with a ground loop. I had a similar problem connecting my JBL104s to the DDJ400 directly. 

I got a new powerboard and connected everything bar the speakers to the powerboard.

Cable management – I made sure none of the power canker or other cables in my setup crossed over the speaker cables connecting the speakers to the laptop by playing the sound through there. I also added a subwoofer recently, so the sound loops from laptop to sub to speakers.

I get no hissing or loud sounds now. I also connected speakers direct to the DDJ to stream the other day, and there was no static or hissing. 

My friend was even smarter. He just ordered a ground loop isolator that goes in the speaker cable line, which sorted his noise issue out immediately.

The ground isolator practically goes into your RCA outputs, and then you put your speaker cables into its outputs. Very cheap and very effective. Probably the best $15 you’ll ever spend.

Buzzing also indicates you’re most likely dealing with ground looping

If you hear buzzing when connecting DDJ-400, it’s most probably ground looping. Can you hear the audio as well, or just buzzing? Does the buzzing go away if you unplug the laptop and run it off the battery? In some instances, the buzzing may also go away when you touch the laptop. 

I had the same issue and had to replace my speakers. 

There are a couple of fixes that will help:

  • Use a ground loop isolator between your laptop and the sound system.
  • Plug your laptop into a different power outlet
  • Use a different power adapter for your laptop

If you’re using Macbook, do you use the original Apple power adapter? I heard people get a buzzing sound when they connect laptops and controllers to their monitors using a cheap power adapter. 

Ground loops are a pain in the butt to track down, but it’s a great practice, as you will run into them frequently as a DJ, especially if you are setting up your own sound systems for parties or running nights at a club (i.e., playing more of a role than just ‘rock up and play’).


Tray Fiddy

Tray has come to terms with the fact he will probably never be a famous DJ.... but that hasn't stopped him from mixing and researching audio equipment. Tray has over 12 years of experience DJing at home and events.

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