Schwung Scratch

Digital vinyl and hands-on sample scratching for Ableton Move and Schwung. Scratch decodes Serato 2nd Edition side A control vinyl from Move's stereo line input. It can also use Move's first encoder or jog wheel when no turntable is available. Pads act as momentary crossfader cuts.

Requirements

• Ableton Move running Schwung 1.5.0 or later.
• A 44.1 kHz, 16-bit, stereo PCM WAV sample.
• For DVS: Serato 2nd Edition side A control vinyl and a stereo line-level turntable output connected to Move's 3.5 mm input.

Convert an MP3 with:

ffmpeg -i input.mp3 -ar 44100 -ac 2 -c:a pcm_s16le output.wav

Main page

Knob	Control
1	Sample browser
2	DVS, Knob, or Jog control
3	Open Scratch View
4	Crossfader (Schwung 1.6 CC-learn target)
5	Hamster mode
6	Loop
7	Low-cut filter
8	Fader cut-in threshold

On Schwung 1.6, start CC Learn, move the Crossfader parameter, then move the hardware fader connected through Move's USB-A port. The older direct CC, channel, and module-local Learn parameters remain available for compatibility with Schwung 1.5 setups.

The second page is DVS Monitor, showing input level, decoder lock, direction, speed, signal quality, and the timecode scope.

Scratch View

Knob and Jog modes expose Feel, Smooth, Inertia, Touch, playback Speed, waveform Zoom, and Motor Play/Stop. In Knob mode, touching Knob 1 stops the virtual record, turning scratches it, and releasing resumes the motor. Jog mode uses the jog wheel. Touch behavior can be disabled, currently detecting a touch is instantaneous, but detecting a release lags enough to annoying.

DVS mode follows the decoded vinyl position and speed. Knob 6 scales playback speed and Knob 7 changes waveform zoom. Press any pad to open the cut; overlapping pad presses retrigger it for crab and transformer techniques. Press the jog wheel or Back to leave Scratch View.

Sample selection and all controls persist with the chain. New instances use the bundled ahh-fresh.wav.

Build and test

./tests/run.sh
./scripts/build.sh

The release archive is written to dist/scratch-module.tar.gz.

License

GPL-3.0-or-later. The timecode decoder is derived from xwax by Mark Hills and retains its upstream notices. See THIRD_PARTY_LICENSES.md and SAMPLE_LICENSE.md.