Novice or professional DJ, when you first lay eyes on the MP2015 most of what you see is intuitive and easily understood. Not a surprise given the mixer was designed with ease of use in mind. But you may be asking yourself, “What is this SUBMIX all about?”
In short, the SUBMIX is a channel that you can send any or all audio to, just as you do with the main mix. The SUBMIX has dedicated gain, 3-band EQ, HP/LP/Combo filter, and external effects processor controls. The concept is identical to a SUBMIX or Bus Track on a typical audio mixing board. This capability is important for grouping a number of tracks together onto one channel for ease of control and processing. The SUBMIX can also be used as a dedicated fifth channel and/or an external effects bus.

Why add a SUBMIX to a DJ mixer?

DJ technology has come a long way and one huge leap forward is the introduction of auto sync. Using CDJs, Traktor, Serato DJ, Ableton, or just about any other DJ software, the sync feature opens the floodgates to creative multi-source mixing.
New technology offers new possibilities. This sometimes requires us to rethink how we mix. One of the biggest perks of the SUBMIX on the MP2015 is it removes the burden of having to simultaneously manage separate gain, EQ, and filter knobs for multiple channels when mixing multiple sources. Grouping the tracks together within the SUBMIX allows one simple set of controls to easily control Mix level, EQ and Filter settings for multiple channels.

Explanation of steps used in the SUBMIX video:

  • I have the main track on Channel 1 and drum loops coming in on Channels 2, 3, and 4.
  • There is a short break coming up in my main track and I want to filter out the tracks coming in on channels 2, 3, and 4 through the short break and back again.
  • Before assigning channels to the SUBMIX you may first want to make certain that doing so has a neutral affect on what is being played:         
  1. Make sure the MIX knob is turned all the way up, EQ knobs are set at 12 o’clock, and the Filter is either turned OFF or turned ON and set to full range within the SUBMIX channel. This ensures that the audio being sent to the SUBMIX is initially unaffected by the SUBMIX routing.
  2. Press the “SUB” button next to the Source knob on both channels 2, 3, and 4. This sends the audio of all three channels to the SUBMIX.
  • At this point you can control all three tracks using the MIX, EQs, or Filter within the SUBMIX.
  • As I get closer to the short break about to happen on the track playing on channel 1, I want to:
  1. Select the type of Filter and make sure it's in the correct position. In my mix I am choosing to use a Low-Pass Filter and I want the entire signal to pass through the Filter unfiltered at first so I position the filter all the way to the far right.
  2. Turn on the filter within the SUBMIX by pressing the Filter ON button.
  3. As I come up on the short break on Channel 1, I start filtering out the frequencies of all the tracks sent to the SUBMIX by turning the Filter knob to the left.
  4. When the short break passes and the bass line comes in on the track playing through Channel 1, I turn the Filter off; bringing back the full frequency spectrum of audio for all tracks sent to the SUBMIX.

Its also worth noting that MIX level, EQ, and Filter adjustments can still be made on the separate channels even after sending them to the SUBMIX, giving you ultimate control of the mix at all times.

Using the SUBMIX as a dedicated 5th channel

Not only can you send any of the four main channels to the SUBMIX, you can also send the audio coming into either the Session Input on the back panel or the USB Session Input; essentially turning the MP2015 into a five channel mixer.

The Session Input on the back panel can receive any line level or S/PID/IF signal. This is where an iPhone or an additional CDJ, for example, can be plugged in.

The USB Session Input sends and receives audio via USB channels 9/10. You can toggle between using the Session Input or USB Session Input by flipping the switch in the Session input section of the mixer. The Session Input has its own level knob that can be used to adjust the input level regardless of it being sent to the SUBMIX. However, sending it to the SUBMIX allows for full MIX level, EQ, and Filter control as well as the ability to group the audio with all other channels sent to the SUBMIX and/or the ability to add external effects to the audio. Lastly, you can cue what is coming in on the Session Input once its been added to the SUBMIX by pressing the Cue button within the SUBMIX. 

To send the Session Input to the SUBMIX simply pressing the SUB button in the Session Input section. Once the Session Input is sent to the SUBMIX the Session Input level knob acts as the 5th Channel's input Gain. 

Adding external effects to the mix

The SUBMIX is also where external effects can be inserted to any or all channels sent to the SUBMIX or Main Mix. On the rear panel you will see RCA jacks for the MP2015's External Effect Loop. You will also see a button that changes the Send and Return levels. If you are using a consumer grade product that outputs at a lower volume this should be set to -10 dbv. When using a pro grade unit that outputs at line level this should be set to +4 dbu. 

At the top of the SUBMIX Channel there is a SUB/MAIN switch, a Wet/Dry knob, and an ON/OFF button for the External FX Loop.

To engage an effect within the SUBMIX:

  1. Select either SUB or MAIN depending on where you would like to insert the effect. 
  2. Press the ON button to engage the effect loop.
  • If SUB is selected for the FX Loop, press the SUB button on Channels 1-4 or the Session Input to send audio to the SUBMIX.

      3. Adjust the Wet/Dry knob to the desired amount.

The effect can also be cued prior to bringing the effected audio into the mix. This is done by sending the desired channel(s) to the SUBMIX, making sure the the SUBMIX MIX level turned all the way down, and pressing the Cue button within the SUBMIX. Once the desired effect is achieved, bring in the affected audio by turning up the MIX level in the SUBMIX.

Note: To avoid common phase issues when connecting external effect units, set the Wet/Dry all the way to Wet and use the Wet/Dry control on the external effect unit to control the amount of the effect.

Summing things up (pun intended!)

As you can see, the SUBMIX and its features make up a very powerful section of the MP2015 without compromising its easy and intuitive interface. Whether a user takes advantage of its grouping capabilities, "extra" Channel, external effect processing, or a combination of all three; the SUBMIX helps pave the way to an entirely new level of precision mixing.