Ableton/Live/UG/31 Instrument Reference/03 Drift
- Drift is a light-on-CPU subtractive synth with a simple interface and full MPE support.
- Six sections: oscillators, filter, envelopes, LFO, Mod and global controls.
- Subtractive synthesis starts from a harmonically rich waveform and carves it with filters. Drift adds modulation on top.
- The Drift control gives each voice small pitch and filter variations, so the tone wavers slightly out of tune.
- Two oscillators, pitch modulation, a waveform display, an oscillator mixer and a noise generator.
31.3.2.1 Oscillator 1
- Waveforms: Sine, Triangle, Shark Tooth, Saturated, Saw, Pulse, Rectangle. Shark Tooth is based on a classic Moog shape; Saturated suits bass.
- Oct transposes by octaves. Shape alters the harmonics, somewhat like pulse-width modulation, differently per waveform; the Waveform Display shows the result.
- Shape Mod Source — Env 1, Env 2/Cyc, LFO, Key (more modulation for higher notes when positive), Velocity, Modwheel, Pressure or Slide, with an amount of -100% to 100%. Shape Mod can move the waveform even when Shape is 0%.
31.3.2.2 Oscillator 2
- Waveforms: Sine, Triangle, Saturated, Saw, Rectangle. Oct in octaves, Detune in semitones.
31.3.2.3 Pitch Mod
- Two sources modulate both oscillators' pitch, chosen from the same list as Shape Mod, each with -100% to 100%. An LFO in Ratio mode on pitch can produce FM tones.
31.3.2.4 Waveform Display
- Shows the combined output of Osc 1, Osc 2 and noise as you edit.
31.3.2.5 Oscillator Mixer
- Switches and gain for Osc 1, Osc 2 and white Noise.
- With filtering on, raising gain drives the filter's two saturation points, before and after the filter, for analog-style distortion: the first engages above the default -6.0 dB, the second above 0.0 dB.
- Arrow toggles beside each gain send that source through the filter; off bypasses it.
- R — Retrigger resets both oscillators' phase on each note; off lets them run free.
- A switchable low-pass filter with key tracking and resonance, a high-pass filter, and two modulation slots.
- Freq — low-pass cutoff. Type — Type I, 12 dB/octave DFM-1 that feeds distortion back internally, from gentle sweeps to warm drive; or Type II, 24 dB/octave Cytomic MS2, a Sallen-Key design with soft clipping that limits resonance.
- Key — 0.00 ignores note pitch; 1.00 makes cutoff follow it.
- Res — low-pass resonance. HP — high-pass cutoff.
- Clicking the section shows an X-Y view: the left dot sets HP, the right dot sets LP cutoff horizontally and resonance vertically.
- Freq Mod — two sources for LP cutoff, each -100% to 100%.
- Envelope 1 shapes amplitude; Envelope 2 is for modulation. Click a section or the 1 and 2 toggles to show one in the display.
31.3.4.1 Envelope 1
- ADSR on the oscillator section's amplitude, set by knobs or in the display. Attack goes from start to peak, Decay from peak to Sustain, Sustain holds until note-off, Release returns to zero.
31.3.4.2 Envelope 2
- Another ADSR, not on amplitude by default, available as a modulation source everywhere in Drift.
- The switch left of Attack turns it into a Cycling Envelope, which acts like an LFO restarted by each note.
- Tilt moves the midpoint, and at extremes the slopes. Hold sets time at maximum. Time modes: Rate (Hz), Ratio, Time (ms) or Sync (beat divisions).
- One LFO with the same four time modes as the Cycling Envelope: Rate, Ratio, Time and Sync.
- Waveforms: Sine, Triangle, Saw Up, Saw Down, Square, Sample & Hold, Wander (S-curves between random values), Linear Envelope and Exponential Envelope (one-shot decays).
- R — retrigger on each note, or free-running.
- Amount — overall depth; a modulation source and amount can modulate the LFO itself.
- Three free slots route a source to a destination with -100% to 100%.
- Sources: Env 1, Env 2/Cyc, LFO, Key, Velocity, Modwheel, Pressure, Slide.
- Destinations: Osc 1 Gain, Osc 1 Shape, Osc 2 Gain, Osc 2 Detune, Noise Gain, LP Frequency, LP Resonance, HP Frequency, LFO Rate, Cyc Env Rate, Main Volume.
- Mode — voice mode:
- Poly — one voice per note, up to 32.
- Mono — one note at a time drawn with four voices; Thickness raises the three extra voices from silent at 0. A new note chokes a held one.
- Stereo — two voices per note panned apart by Spread.
- Unison — four voices per note detuned by Strength.
- Voices — total voices. At 32: Poly plays 32 notes, Stereo 16, Unison 8.
- Drift — scales each voice's own random offsets to oscillators and filter; more sounds more out of tune.
- Legato (Mono) — new notes change pitch without restarting envelopes; Glide sets the slide time.
- Volume and Vel > Vol — level and how much velocity affects it.
- Transpose — ±48 semitones. Note PB — per-note pitch bend on or off, so an MPE controller can be used without finger position changing pitch. PB Range — pitch bend range.
