III.a – DJ music chain in practice

As we’ve said before, there are many different ways to handle the DJ playing process, with many different software and hardware choices available. It is really comfortable to handle most tasks within the computer itself. One program that is able to do that, on a Mac, is Audio Hijack 3. It is a platform that enables you to take control of the audio interface of the computer, enhance it with plugins to route music from playback softare to chosen outputs. I’ve been streamlining the process while editing this wabsite. This is the present version of my setup:

1. Input

The first module are the inputs into the sound chain. In this setup there are two, Embrace, which is my preferred player program at the moment, and a dynamic microphone, plugged into one of the inputs on the Scarlett 2i4 external soundcard. The two inputs are linked to a ducking filter. It is set so as to output music from Embrace at full volume most of the time, while keeping the microphone input turned off. If, however, I speak into the mike the ducking filter automatically lowers the music so that I can speak over it.

2. Compressor

When working with weak systems a compressor can be useful in order to increase the general sound of the music, as it can function to flatten the frequency curve of the songs and thus generating denser sound at lower volumes. This does change the balance between different frequencies in the songs and must therefore only be used with care. I use MCompressor, a plugin from Melda Productions, for eventual compression should the occasion arise. More on this in V.e.

2. Parametric equaliser

The second part of the DJ chain is the parametric equaliser, used to individually adjust individiual tracks, correcting them for playback. This example uses MEqualizer from Melda Studios, the same we’ve been using for our examples of equalisation. It includes a handy visual interface where you can adjust equalisation and see how the sdjustment is affecting individual tracks being played. Track equalisation will be tackled in V.b and V.c.

3. Venue equaliser

The third element handles specific ecqualisation of the space the music is being played in.  In this case it is a solution from MathAudio called RoomEQ. This is a plugin that can analyse the acoustics of a space and equalise them out, creating a flat responce curve for playback by counteracting the diversion from uniform frequency in the speaker setup itself. This module accepts the equalised tracks from the parametric equaliser and modifies them for playback.

4. Loudness analyser

The loudness analyser is a tool that displays visually most of the important details of the music being performed. Using it after equalisation enables me to be sure that everything is in balance and functioning the best it can. I also can use the loudness analyser to adjust the overall gain, which may be needed as RoomEQ flattens the frequency curve and doing so lowers the general volume of the music. When I need to output the music at full volume, the loudness analyser enables me to do so in a secure way.

5. Peak limiter

At the end of the chain I include a peak limiter, as a final security option. It is preferable to output the music from the computer at full volume, especially if the house speaker system is on the weaker side. The peak limiter functions to cut out any unforeseenhigh volume sounds that mightlead to distortion and damage the speakers.

6. Output

The final part in the DJ chain is the output device. Here it is a Scarlett 2i4 USB which is used as a DAC. Channels 1 and 2 are used for the signal to  the equaliser/speaker system, with fine adjustments in volume done in the Scarlett device. We will go into this in better detail in part VI.a.

7. Secondary chain

Above the main chain is a separate chain, comprising of an input from ITunes and another output to the Scarlett 2i4. This is used for prelistening tunes. They are routed to channels 3 and 4 on the Scarlett, connected to the headphone output on the device. When using a setup like this, care must be taken that system sounds are not set to output to the Scarlett device.

7 thoughts on “III.a – DJ music chain in practice”

  1. Igor El Espejero says:

    Great setup!I like the way how you managed to route all four channels into 2i4.

    1. Hlynur Helgason says:

      Thank you very much for your encouraging reply, Igor. Actually, I’ve been working on this setup a bit more, editing the post with that in mind. I’ve added a ducked microphone input to the Scarlett at the beginning, placing the compressor up front (as you suggest on your site), and added a loudness analyser at the end to keep a check on everything, with a simple peak limiter for safety at the very end. This gives me the utmost flexibility when trying to manage dodgy sound systems.

  2. Marquis Childs says:

    Hi Hlynur

    I have a Scarlett 2i2. Do you have to use a 2i4 for the above set up, or is there a way to use the 2i2? I currently use Embrace and put it in hog mode so I can pre-cue the music in iTunes via the computer headphone jack, (before I send whatever I want over to the Embrace player), all while the playlist is running.

    Would it not be possible to continue to do things like I currently do, (i.e., place iTunes prior to Embrace in the audio chain, with Embrace in hog mode so I can pre-cue off the laptop) , and then set up the rest of the audio chain as you have it shown above?

    Also, what ducking filter do you use? I’m also not clear on how you connect the mic and Embrace to the ducking filter.


    1. Hlynur Helgason says:

      Hi Marquis,
      You can use a similar setup with the Scarlett 2i2, but with the Headphone-output as an output from the ITunes chain, instead of outputs 3/4 I use on the Scarlett 2i4.
      The way I set it up there is a separate audio chain for pre-cueing, so you do not have to chain ITunes before Embrace, they run on separate chains within the Audio Hijack interface.

      Audio Hijack inclutes quite a versatile ducking filter (you find it under ‘Advanced’ in the filter setup). that you place after your two inputs, i.e. the Scarlett 2i2 input and the Embrace input, at the beginning of the DJ chain, with both linked into the ducking.

      1. Marquis Childs says:

        Okay, thanks! Glad to know it’ll work with my 2i2.

        I’m curious though, why do you feel a need to run iTunes on a separate chain from Embrace? Is there any advantage to that? Or is it because you simply are able to because you have a 2i4?

        1. Hlynur Helgason says:

          Well, Embrace runs through a more complex chain, with an equaliser, compressor, a room equaliser, on its route to the main speaker system. ITunes only needs an equaliser on way to the headphones, so you need a different setup for different outputs. I hope this answers your question.

          1. Marquis Childs says:

            Okay yes, I think I get it. With Audio Hijack I would send the music on Embrace via one chain to the Scarlette 2i2, and with the other chain, (since Audio Hijack only splits the audio into two channels), send iTunes out through the computer.

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