The best way to unlock the hidden potential of any semi-modular synthesizer is by sequencing. This post will describe the necessary steps to use the QuNexus as a MIDI-to-CV converter along with Ableton Live to control the legendary Oberheim Synthesizer Expander Module.
Before you begin, make sure you have an SEM or any other modular or semi-modular synth, a computer with Ableton Live installed, a QuNexus and the QuNexus CV Cable Kit.
First, you’ll want to create a loop of notes so connect the QuNexus to your computer and open the Ableton Live app. Within Live’s session view, create a MIDI track and double click on a clip slot to create MIDI Clip then enter in some notes. Also set the MIDI track to output to ‘QuNexus (Port 3)’ on Channel 2. If the QuNexus doesn’t appear in the MIDI To dropdown menu then you’ll need go to the MIDI tab of the preferences window and set ‘Output: QuNexus (Port 3)’ to On for Track and Remote.
Next you need to patch from the QuNexus CV outputs into the SEM CV inputs so plug one of the TRRS to dual mono cables into the QuNexus output port labelled “Gate – CV 1”. Then plug the gate end, which is white, into the SEM’s Env1 Gate input and the CV1 end, which is red, into the SEM’s VCO1 CV1 input. Make sure to set your two VCOs to EXT so that they will respond to the CV input.
At this point you should be able to hit play on your MIDI clip in Live and hear your sequence coming out of the SEM’s audio output jack. What’s going on here is that the MIDI notes are being sent to the QuNexus and then are converted into a pair of CV signals where the gate signal is triggering note on/off events and the CV1 signal is controlling the oscillator pitch.
There’s still two more CV outs use so plug a second TRRS to dual mono cable into the QuNexus CV out jack labelled CV 2-3. In order to have control over the filter cutoff frequency and the volume, plug the white CV 2 end into the SEM’s VCF CV1 input and the QuNexus red CV 3 end into the SEM’s VCA CNTL input. On the synth set the VCF to EXT and turn the EXT knob fully counter clockwise in order to have the filter properly track the CV input. Also there’s a switch that enables external VCA control between the two envelope generators that is labelled ON/EXT, switch it to the right.
In the QuNexus Editor’s CV tab assign MIDI Types for CV 2 and CV 3 to CC#002 and CC#003 respectively then hit save and send to your desired preset slot. Which CC#s you choose is arbitrary but 2 and 3 are good choices because they correspond to the QuNexus CV numbers and so they will be easier to remember when within Live. You can now quit the QuNexus editor.
In Ableton Live, double click on your MIDI clip and click the E icon on the bottom of the window to show the envelopes box. Your envelopes box will have two dropdown menu’s, on the top select MIDI Ctrl and on the bottom select “2 – Breath”. This is your Filter envelope. You can ignore the word “breath”, the important thing to know is that you are modifying CC#2 which the QuNexus will output as CV 2. Draw some automation in the envelope and hit play on your MIDI clip. You should hear your filter cutoff frequency animating accordingly.
The last step is to click again on the lower dropdown menu and this time select 3. If you now draw in automation on this envelope you will hear the volume of your synth get louder and softer depending on your automation values.
As you can quickly see, the possibilities are vast for creating many kinds of expressive sequences. Try sequencing other parameters on the SEM such as Pulse Width Modulation, VCO2, LFO Trig, and Envelope 2.