Three oscillators into a ladder

The oscillator chapter ends with the Moog recipe's core — the three-voice saw stack and the driven ladder — and ranks what each ingredient buys. This recipe finishes the instrument: the two envelopes, the amplifier, the gate, and the settings that turn one signal chain into the two patches everyone actually means by "Moog" — the bass that walks and the lead that sings. The model here is the classic three-oscillator monosynth voice: three oscillators into a mixer, one four-pole ladder, one loudness contour, one filter contour, glide on the pitch. Nothing below requires an object the package doesn't ship. And once the voice stands, the next recipe drives it at the records with names on them — Winwood, Worrell, Wright, Emerson.

Companion material: the oscillator chapter (the stack's rationale and the analog section's ranges), the ladder chapter (every filter number below is measured in its notebook), and the reference pages for tap.adsr~ and tap.vca~.

The voice, wired

pitch (midi note) ──▶ mtof ─┬─▶ tap.vco~ (voice 1)──┐
                            ├─▶ tap.vco~ (voice 2)──┼─▶ *~ 0.36 ─▶ tap.ladder~ ─▶ tap.vca~ ─▶ out
                            └─▶ ÷2 ─▶ tap.vco~ (3)──┘                    ▲              ▲
gate (0/1 signal) ──┬───────────▶ tap.adsr~ (filter contour) ─▶ *~ amount ─▶ +~ base ──┘│
                    └───────────▶ tap.adsr~ (loudness contour) ─────────────────────────┘

• Pitch arrives as note frequencies (floats into each tap.vco~ left inlet; halve for voice 3's octave-down). The oscillators' own smooth ramp is the glide knob — no portamento object exists or is needed.
• Gate is any signal that rises above tap.adsr~'s threshold and back — the envelope reads the gate by level, per sample. A tap.303.seq~ gate output (1.0 plain, 2.0 accented) drives it directly, which also gets you slides for free; so does a MIDI-driven 0/1 signal, or the trigger 1 / trigger 0 attribute messages for mouse-driven patching. The default mode analog gives the envelopes below the RC curves a Model D actually had; velocity (off by default) lets the gate's amplitude scale the hit.
• The filter contour scales into the cutoff's signal inlet: envelope × amount (Hz) + base (Hz) into tap.ladder~'s right inlet. The classic panel's "amount" knob is your *~.
• The loudness contour multiplies the ladder's output — tap.vca~ with the envelope into its gain inlet keeps the option of @circuit warm saturation later.

One period-correct honesty note: the original panel's contours are attack/decay/sustain with a release switch (release equals decay, on or off). tap.adsr~ gives the full four stages; set release equal to decay and you have the switch's "on" position.

The stack and the ladder

The three-voice table is the oscillator chapter's, reproduced so this page patches alone:

All three: @shape 2 (saw), @jitter 3 @track 2 @imperfect 0.3, and smooth per the patch below. Sum through *~ 0.36 (≈ 1/2.8, headroom for three voices), then tap.ladder~ at the chapter's voicing: @mode lp24 @resonance 0.35 @drive 9 @asym 0.45 @comp 0.25. Keeping comp low preserves the authentic passband droop; drive 9 sits where the ladder notebook measures the tanh stages just starting to thicken (3.5 % THD at 8 dB). Spend the character budget in the filter first — the chapter's measurements are the argument.

Patch one: the bass

The left hand of a decade of records: short filter contour, no vibrato, glide short enough to read as punch rather than portamento.

The sound lives in the filter contour's decay: 220 ms is the "wah" that articulates each note. Shorten toward 120 ms and it turns percussive; lengthen toward 400 ms and it turns brassy. For a rounder, more sub-friendly bass, drop drive to 3 and asym to 0.2 — the even harmonics are lovely on a lead and muddy on a bass amp. If anything downstream cares about DC, remember the ladder chapter's warning: an asymmetric saturator can leave a small signal-dependent offset — tap.dcblock~ after the VCA is one object of insurance.

Patch two: the lead

The singing version: longer glide, opened filter, resonance high enough to color but under the edge, and the release switch "on."

Two moves push it from good to that sound:

• Play the glide. 80 ms of smooth means overlapping note changes swoop; detached ones barely bend. The keyboard articulation is the vibrato.
• Lean on the octave voice. Pull voice 3 up to f (unison) for the hollow reedy register, or leave it at f ÷ 2 and drop voice 2's level for the fat fifth-less stack. The interp-timed preset morph (store / recall <slot> <ms>) can glide between these voicings mid-phrase — a patch element the hardware never had.

What each ingredient buys

In order — and, per the house rule, cut from the bottom when CPU or taste says so:

1. The stack. Three free-running voices at ±cents is most of the sound (the oscillator chapter's argument, with its measurements).
2. The ladder. Drive, asymmetry, and the low-comp droop — the character budget.
3. The filter contour. The one envelope listeners hear as "the synth's voice." Its decay is the most audible 100 ms in the patch.
4. Glide. Free, iconic, already in the oscillator.
5. The loudness contour. Keep it simple; the filter does the talking.
6. The analog section. drift/jitter/imperfect at the chapter's moderate settings — salt, not sauce.

When to leave the recipe

• You want polyphony. This is a monosynth voice; mc.-wrapping the whole chain gives you many monosynths, and a real polysynth patch wants per-voice envelopes and different discipline.
• You want the 303 instead. The couplings that make acid are a different instrument — tap.303~ refuses to be decoupled, and that refusal is its chapter.
• You want clean. Every stage here has an opinion — tap.svf~ and tap.fourpole~ are the polite siblings when the patch needs a filter, not a character.