The ostinato machine

Two documented lineages share one patch. The Berlin school — Tangerine Dream's Phaedra (1974) above all — put a Moog modular's step sequencer on stage and let a filtered ostinato run for twenty minutes while hands moved the cutoff. Three years later Giorgio Moroder and Donna Summer's "I Feel Love" built an entire hit from a sequenced Moog modular bassline. The Recipes part's Moog chapter argued you already own the modular — Max is the patch panel; this recipe is that argument cashed in: the sequencer pair driving the three-oscillator voice.

The scaffold

phasor~ (BPM/240) ──▶ tap.303.seq~ ──pitch──▶ mtof~ ──▶ slide~ ─┬─▶ tap.vco~ ──┐
                                  │                             └─▶ tap.vco~ ──┼─▶ *~ ─▶ tap.ladder~ ─▶ tap.vca~
                                  └──gate──┬─▶ tap.adsr~ (filter) ─▶ *~ amount ─▶ +~ base ──▶ ▲ (cutoff)
                                           └─▶ tap.adsr~ (loudness) ────────────────────────────▶ ▲ (gain)
  • tap.303.seq~'s pitch outlet is a MIDI-note signal; mtof~ turns it into Hz for the oscillators' signal inlets.
  • Its gate outlet (1.0 plain, 2.0 accented) drives both tap.adsr~ contours directly — the envelope opens above 0.5.
  • One honest wrinkle: tap.vco~'s frequency signal inlet bypasses the smooth ramp by design ("you are the smoothing") — so sequenced pitch steps land as hard steps, and slide flags in the pattern won't glide on their own. Put a one-pole slew (Max's slide~, or rampsmooth~) between mtof~ and the oscillators; the 303's ~60 ms RC is the reference feel. Short slew = articulation, long slew = the Berlin swoop.
  • The oscillator stack, ladder voicing, and envelope tables come from Three oscillators into a ladder — the bass patch is the right starting point. One voice instead of three is period-correct for the sequenced genre and cheaper; add the stack when the line is the whole arrangement.

The line

The genre's cell is small and the sequencer's phase math does the rest (one bar per phasor cycle; a length 8 row divides it into eighths — polymeter as arithmetic, per the sequencer chapter).

The octave bounce, "I Feel Love"-school — length 8, every step gated:

step:    1  2  3  4  5  6  7  8
pitch:   33 45 33 45 33 45 33 45

pitches 33 45 33 45 33 45 33 45
gates   1 1 1 1 1 1 1 1

The Berlin cell — length 16, a contour that repeats but doesn't resolve:

pitches 33 33 40 36 33 43 36 40 33 33 40 36 31 43 36 38
gates   1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Then the two moves that carry twenty minutes:

  1. Transpose, sparsely. transpose 0 → 3 → 5 → 0 at phrase boundaries is the harmonic language — one message, and the armed pattern semantics keep everything on the grid.
  2. Ride the filter, slowly. The loudness contour stays short and percussive; your hand (or a very slow LFO into the +~ base) opens the ladder over minutes, not bars. The ostinato doesn't change; the light on it does.

Settings that read as the genre

controlsetting
loudness tap.adsr~@attack 2 @decay 180 @sustain -12 @release 120
filter tap.adsr~@attack 2 @decay 160 @sustain -20 @release 160, amount 1800 Hz, base 150 Hz
ladder@mode lp24 @resonance 0.3 @drive 6
slew (slide~)short; raise it only for deliberate swoops
seq@swing 0 — the genre is a grid, and the delay does the humanizing

Two period tricks worth their lines: pan alternate notes (a length 8 row of accents driving tap.pan~ recreates the famous ping-pong doubling), and put an eighth-note tap.delay~ after the voice (@feedback 40 @mix 30) — the echo, not the sequencer, is where these records' motion lives. Since its rebuild the delay interpolates (Hermite) and regenerates through a DC-blocked loop; @interp 0 remains the bit-faithful legacy mode.

Glue: an 808 closed-hat row in 16ths from the drum scaffold, mixed low. Accents land in this scaffold too: turn up tap.adsr~'s velocity sensitivity and the sequencer's 2.0-amplitude accented gates hit the envelopes harder — the loudness contour for punch, the filter contour for the quack, or both.

When to leave the recipe

  • You want the 303's couplings — slides that bloom, accents that squelch. That's the acid recipe; this scaffold trades the couplings for a filter and envelopes you choose.
  • You want generative movement. This sequencer is deliberately deterministic; probability and ratchets are future emitters, and randomness belongs to objects that own a seed.
  • The line wants to be a song. Sixty-four steps is the ceiling; past that you're composing, and a piano roll is kinder than sixty-four step messages.