A simple program to be able to control the FractalAudio Axe-Fx II guitar processor with a Native Instruments Rig Kontrol 2. Both devices are connected to a linux box via USB.

First, make sure the Axe-Fx is recognized by linux. See the linux and fxload notes on the Axe-Fx wiki.

Then, we're lucky, necessary ALSA drivers for the Rig Kontrol 2 are included in kernel versions 2.6.22 and above. axerig2 translates the Rig input events to midi CCs and send them to the Axe-Fx.

The Rig's seven foot switches and the pedal are configurable via a simple config.json file.

{
  // Rig Kontrol 2 input device
  "rig_device": "/dev/input/by-path/pci-0000:00:1a.0-usb-0:1.1-event",

  // Axe-Fx midi port
  "axe_midi": {
    "port": "AXE-FX II",
    "channel": 0
  },

  // foot switch
  "switch": {
    "1": { "cc": 121 },// looper undo
    "2": { "cc": 32 }, // looper reverse
    "3": { "cc": 30, "toggle": true }, // looper once
    "4": { "cc": 28 }, // looper record
    "5": { "cc": 29, "toggle": true }, // looper play
    "6": { "cc": 31 }, // looper dub
    "7": { "cc": 122, "toggle": true }, // metro // 120 looper half
    "pedal": { "cc": 17 } // external controller 2
  }
}

Dependencies: ALSA, boost header only for the property_tree library, GCC 4.4 or more with -std=c++0x.

$ INCLUDES="-I/path/to/boost/include" make

Plug the Axe-Fx and the Rig Kontrol to your computer via USB.

Prior launching axerig2 you probably want to prevent the Rig input events to be handled as keyboard events. One solution is to disable the device with xinput as shown bellow.

Edit config.json to match your Rig device. The Axe-Fx midi specs should remain unchanged. Configure the switches CCs.

$ xinput --set-prop "RigKontrol2" "Device Enabled" 0
$ ./axerig2

Axe-Fx MIDI CCs list

Axe-Fx forum