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14. How to make a synth patch respond to aftertouch

1 Most modern keyboard controllers are capable of generating aftertouch, but to check whether or not yours does, launch your DAW and press down firmly on some keys on your controller, while watching your computer screen. If your DAW’s MIDI activity indicator flashes as you press down and release, you’re generating aftertouch data.

2 If the test works, you know you can program aftertouch response into a patch in any synth that supports it. For example, if we load up Dune CM’s 022 Earth Views RL preset and play a few notes, we can hear that there’s no change to the sound when we press down on the keys after the initial impact, so no response to aftertouch has been set up.

3 We can use aftertouch to open the filter, so the sound gets brighter as we press down on the keys. In Dune CM, aftertouch is labelled as ATouch, and is assigned to your desired parameter in the main modulation matrix window in the LCD panel in the centre of the synth’s control panel. Click the button labelled Mod Matrix 1>12 to access this.

4 Clicking on the Source column in the first empty row of the matrix (row 4 in this case) reveals a list of all the applicable sources for us to choose from. To select aftertouch, choose the ATouch item from the menu. It can be found by looking for the fifth one down from the top.

5 We want the aftertouch data to control the filter’s cutoff frequency, so select Filters > Filter Cutoff in the Destination column. The routing is now all set up, so set the amount of effect generated when we press down on the keys. A setting of about +50 is a good starting point. Enter this in the centre column.

6 Now, when we hold a note down, we can control the opening and closing of the filter by how hard we press on the key. In the case of channel aftertouch, since the effect is generated by one long sensor beneath the keys, you only need to press with one finger, not all of them, when holding down a chord.