Buchla Easel V

How it works

West coast versus east coast

In east coast synthesis (Moog) you start from rich waves and subtract with a filter. In west coast synthesis (Buchla) you start from simple waves, often a sine, and add harmonics with waveshaping and with modulation between oscillators; volume and brightness are controlled together with the Lo Pass Gate.

Complex oscillator and wavefolding

Wavefolding takes a wave and, when it exceeds a certain threshold, folds its peak back inward; as you increase the gain the wave folds several times, creating ever more jagged shapes and therefore ever higher harmonics. The timbre thus grows in a nonlinear, bright way, with harmonic peaks that shift as you move the Timbre control: an almost vocal movement, very different from the opening of a filter.

Modulation oscillator

A second oscillator can work as an LFO (low range) or at audio frequency (high range) and is wired internally to the first: in FM it modulates its frequency (sidebands, metallic timbres), in AM it modulates its amplitude (new sum and difference frequencies, low-frequency tremolo), or it becomes a ring modulator with an external signal.

Lo Pass Gate

The Lo Pass Gate is a gentle low-pass filter (12 dB/octave) and a VCA in one, controlled by a vactrol (an LED coupled to a photoresistor). When a voltage pulse arrives, the LED lights up and the photoresistor reacts with a slight delay and a natural decay: the sound opens and closes in a physical way, bright on the hit and progressively darker. In filter mode it controls only brightness, in VCA mode only volume, in combined mode both (the classic bongo sound).

Control voltages and randomness

The control sources (Pulser, AHD envelope, 5-step sequencer, random voltage generator, keyboard voltage presets) are connected with cables to the black inputs; everything can modulate everything. Music often arises from relationships between clocks, sequences and randomness rather than from the keyboard: that is why the Buchla is the instrument of generative music.

Character and tone

Organic, lively, spherical sound: the complex oscillator starts from a sine and, with wavefolding, is enriched with harmonics in a bright, metallic way, very different from the cut of a filter. The vactrol Lo Pass Gates make every hit naturally brighter when loud and darker as it decays, with a soft decay and a slight ring: the famous percussive sound reminiscent of bongos, marimbas and drops. Strong in the mids and upper mids (300 Hz–5 kHz), lighter in the deep bass than a Moog. It excels at generative sequences, constantly evolving timbres, and FM and AM between two oscillators. Limitations: poorly suited to fat pads and heavy basses, a counterintuitive interface (time sliders up = fast), polyphony limited to 4 voices, only two oscillators. Compared to Modular V and ARP 2600 V (east-coast, subtractive) it is the opposite approach: you add harmonics instead of removing them; compared to Synthi V it is more musical and in tune, less chaotic.

Architecture

Original Buchla Music Easel (1973)

• Designed by Don Buchla (who had built the first Buchla 100 modular for the San Francisco Tape Music Center in 1963–65); a portable suitcase system made up of the 208 Programmable Sound Source module and the 218 touch-plate keyboard.
• 29-key capacitive keyboard with no moving parts, with pitch, gate and pressure output; controllable portamento, arpeggiator, clock, three voltage presets, octave switch.
• Complex Oscillator (a sine that turns into pulse, square or triangle via timbre/wavefolding) and Modulation Oscillator (sawtooth, square, triangle, low/high range, FM, AM or balanced modulation).
• Vactrol Dual Lo Pass Gate (filter, VCA, combined modes), Pulser, three-stage Envelope Generator (attack, sustain, decay) with sustained/transient modes, 3–5 step Sequential Voltage Source, Random Voltage Source, Inverter, Pre-amp/envelope follower for external signals, spring reverb; patching with shorting bars and stackable cables; programming card to store patches.
• Monophonic.

Buchla Easel V (Arturia, 2016)

• TAE modeling; chromatic quantize on both oscillators; polyphony of up to 4 voices; self-trigger mode of the Envelope Generator (it becomes a complex LFO); noise and feedback in the pre-amp; velocity, mod wheel and key follow as patchable sources; keyboard with 4 voltage presets (instead of 3).
• Advanced Universe: Left Hand with 5 drawable Function Generators (curves with level, rate, slope, randomization, Once/Loop/Run modes, sync, humanize, smooth) assignable to almost every parameter; Right Hand, a 32-step polyphonic sequencer transposable from the preset pads; Gravity, a physical world with projectile, planets, repellers, walls and wormholes that generates X/Y modulations and impact triggers.
• Gate Response of the Lo Pass Gates (fast/slow) and gate or trigger behavior of the Pulser; two effects slots (Flanger, Phaser, Chorus, Delay, Analog Delay, Overdrive, Destroy, EQ4, Compressor, Reverb) in addition to the emulated spring reverb.

The controls, one by one

Complex Oscillator

Pitch (right slider)

Tuning over 5 octaves (55–1760 Hz scale printed beside it); 440 for the standard register.

Pitch CV (left slider)

Amount of the voltage entering the black pitch input (sequencer, preset, random, function generator).

Fine tune

Fine tuning.

Keyboard on/off

Whether the oscillator follows the keyboard: off for experimenting with timbres and drones, on for melodies and arpeggios.

Quantize

Quantizes the pitch to the chromatic scale (Arturia addition): sequences always in tune.

Timbre (slider)

Amount of wavefolding: down is an almost pure sine, up is a very rich folded wave. It is the west-coast cutoff.

Timbre CV (slider)

Amount of timbre modulation from the input: envelope or LFO on the timbre = a timbre that speaks.

Timbre dial and shape switch

Mixes the folded sine with pulse, square or triangle (chosen with the switch).

Modulation Oscillator

Frequency (slider) and Frequency CV

Frequency and amount of external frequency modulation.

Fine tune

Fine tuning.

Keyboard on/off and Quantize

Keyboard tracking (for constant FM ratios) and quantization (high range only).

Range High / Low

High = audio oscillator; Low = LFO (about 0.17–55 Hz). In low with FM and a frequency of 5–6 Hz = vibrato; with AM = tremolo.

Waveshape

Sawtooth, square or triangle.

Modulation switch (bal.ext / a.m. osc / f.m. osc)

Normal output or balanced modulator (ring) with an external signal; AM or FM on the Complex Oscillator (internal connection, no cables).

Modulation (slider) and base level slider

Amount of modulation applied to the Complex Oscillator and minimum level.

Dual Lo Pass Gate

Mode switch Gate 1 and Gate 2 (filter / VCA / combined)

12 dB low-pass filter, volume only, or both (natural percussive sound with the Pulser).

Gate 2 source switch

Gate 2 processes the Pre-amp (external audio), the Modulation Oscillator or the Complex Oscillator (gates in series).

Level 1 / Level 2 (manual sliders)

Base opening of the gate (no sound at zero).

CV in 1 / CV in 2 (sliders)

How much the control voltage (envelope, Pulser, sequencer) opens the gate.

LED

Show how much signal is passing.

Pulser

Trigger select (Keyboard / Sequencer / Self)

What starts the Pulser: keyboard, sequencer or free self-oscillation.

Mode (Sync / Free / Clock)

Synced to tempo, free, or retriggered on every clock pulse.

Period (slider)

Pulse duration from 0.002 to 10 s; up = fast, down = slow.

Period CV (slider)

Period modulation from other voltages (e.g. pressure, envelope, random).

Yellow outputs

Three identical copies of the pulse: trigger for envelope, sequencer, random, gate (percussive AD envelope).

Envelope Generator

Trigger select (Keyboard / Pulser / Sequencer)

Start source.

Mode (Sustained / Transient / Self)

Sustained: holds as long as you press the key; Transient: always runs all stages with fixed durations (percussion); Self: continuous cycle, it becomes a three-stage LFO (Arturia addition).

Attack (rise)

Rise: slider up = fast, down = slow.

Sustain (hold)

Duration of the hold stage (in transient) or time added to the key press.

Decay (fall)

Fall to zero; sustain and decay both long can overlap (as on the original).

Orange outputs

Envelope to gate, timbre, pitch, Pulser.

Sequential Voltage Source

Trigger select (Keyboard / Pulser / Clock)

Advances on every key, on every Pulser pulse or on every clock pulse (syncable to the DAW).

Stages (3 / 4 / 5)

Number of steps: 3 and 5 for odd cycles and polyrhythms.

Step switches

Determine how some steps are treated (step triggers) for rhythmic variations.

Step sliders

Voltage per step: with the value 10 and the Complex Oscillator at 110 you get octave jumps.

Blue outputs

Two sequence outputs (pitch, timbre, Pulser speed, portamento, gate).

Random Voltage Generator

Trigger select

New random value on every key, Pulser or sequencer.

White outputs (4 different)

Four independent random voltages: small doses on pitch or timbre = life; high doses = sci-fi bleeps.

Patch bay and colors

Black inputs

Gate 1 and 2 level, Complex timbre and pitch, Modulation frequency and range, Pulser, Inverter, keyboard inputs (each input accepts only one cable).

Colored outputs

Blue MIDI and sequencer, orange envelope, purple pressure, white random, yellow Pulser; up to 3 cables per output. When you drag a cable, circles appear on the compatible inputs.

MIDI connections

Velocity out, Wheel out, Key Follow out

Velocity, mod wheel and keyboard position as patchable voltages (e.g. velocity on the Gate for dynamics, key follow on the gate for brighter high notes).

Pressure (purple)

Channel or polyphonic aftertouch from the external controller.

Keyboard section

Clock (rate, sync/free)

Central clock; in sync it follows the DAW with start/stop and song position.

Pulse out

Pulse tied to the press of a key, usable as a voltage.

Portamento (dial and CV in)

Slew of the keyboard voltage after the arpeggiator; modulatable (e.g. random = variable glide).

Arpeggiator (rate, CV in, sync, walk, range)

Ascending or random; extension over octaves or over the voltage presets.

Octave switch

Adds or subtracts one volt per octave.

Preset Voltage Sources (4 pads and dials)

Voltage offsets added to the keyboard (transpositions, intervals) or used as patchable control knobs.

Output Section

Mod CV out

Control output of the Modulation Oscillator to other destinations.

Env Out

Output of the Pre-amp's envelope follower.

Channel A / Channel B

Output levels of the two gates (A usually the Complex, B the Modulation or the pre-amp or the sum in antiphase).

Reverb (mix and on/off)

Spring reverb emulation: vintage atmosphere, times modulatable from Left Hand and Gravity.

Master Volume

Final volume after the reverb.

Pre-Amp (Envelope Follower / Noise / Feedback)

Envelope follower for external audio, noise (Arturia addition) or feedback loop on Channel B (watch the levels).

Inverter

Inverts a voltage: mirrored sequences between the two oscillators, alternating gates.

Bottom bar

MIDI Channel, Panic, CPU

Channel, note reset, load.

Maximum Polyphony

From 1 to 4 voices (assignable via MIDI).

Universe — Left Hand (5 Function Generators)

Slot 1–5 on/off and amount

Turns the functions on and sets their amount toward the destination.

Destination and parameter

Almost every module: sequencer, envelope, Pulser, oscillators, gates, output, keyboard, other function generators, Right Hand, Gravity.

Curve (points, Level, Rate, Slope, Rand L, Rand R)

Drawing of the voltage with points, curvature and per-point randomness.

Once / Loop / Run modes

Once per trigger, in retriggerable loop, free-running locked to the song position.

Rate and Tempo Sync

0.1–20 Hz or synced.

Random (humanize) and Smooth

Global randomness multiplier and slew limiter (up to about 300 ms).

Universe — Right Hand (32-step sequencer)

Length and note grid

Up to 32 steps; notes and chords (requires polyphony > 1) drawn on a grid.

Preset lane 1–4

Per-step transposition with the keyboard's Preset Voltages.

Once / Loop / Run modes and Tempo Sync

Playback per held note, looped or free; sync from 4 bars to 1/128.

Gate Length and Gate Random

Duration of the gates (0.01–0.99, added to the sustain in sustained mode) and its randomness.

Universe — Gravity

Launcher

Launches a projectile when a key is pressed (or from the Pulser/sequencer); direction and force by dragging the tip of the arrow.

Objects: Repeller, Planet, Wall, Wormhole

They repel, attract, block (active walls generate triggers) or teleport the projectile; up to 4 per type.

X and Y destinations with amount

The projectile's position becomes two modulations (e.g. Y on pitch, X on timbre).

Mode Once / Loop / Run and Rate

Life of the projectile: as long as you hold the key, relaunched periodically (0.025–0.5 Hz or 1–8 bars), or perpetual.

Trigger Source (Key / Pulser / Seq)

What launches the projectile.

Impact Gate (Horiz, Wall, objects) and Length

Triggers generated on impacts with a duration of 5 ms–4 s: generative rhythms.

Physics: Force, Random Throw Dir

Attraction/repulsion intensity (0–8) and randomness of the launch direction.

Universe — Effects and Gate Response

Gate Response (Fast / Slow)

Behavior of the vactrols: fast for dry attacks and decays, slow for soft hits and long tails.

Pulser Gate

The Pulser behaves as a gate (hold/release) or a trigger (release only).

2 effects slots

Flanger, two-stage Phaser, Chorus, Delay (9–999 ms, sync, link, ping pong, damping), Analog Delay, Overdrive, Destroy, EQ4, Compressor, Reverb (Pre-delay, Room Size, Width, Tone, Tame, Gain), each with Wet/Dry.

Sound design tips

Think the opposite of a Moog

• Start from a simple timbre (low Timbre) and add harmonics with wavefolding or with FM/AM; don't look for a resonant filter: brightness is controlled by Timbre and the Lo Pass Gate.
• Remember the rule of the time sliders: up is fast, down is slow (Pulser, envelope). Always start from the top and come down.

Lo Pass Gate

• Combined mode + short Pulser = natural percussive hit: vary the Pulser period to go from drop (very short period) to marimba (medium) to damped bell (long).
• Gate Response Slow for soft sounds and long tails; Fast for dry, quick rhythms.
• A gate at zero lets nothing through: if you hear no sound, check Level, CV in and the Channel A/B volumes.

Wavefolding and frequencies

• Wavefolding brings energy above 2–3 kHz very quickly: on high notes or with a lot of FM the sound becomes shrill. Use key follow or an inverted voltage on the timbre for high notes, or the EQ4 to smooth 4–8 kHz.
• For basses keep Timbre low and leave the body to the fundamental sine; add weight with the Modulation Oscillator an octave below in light AM. Don't expect a Moog-style sub: if you need one, pair it with a sub from another instrument.
• In FM keep the Modulation Oscillator on Keyboard on and Quantize on: the ratio stays constant and the notes stay in tune; when disconnected from the keyboard every note changes timbre (useful for effects).

Movement and generativity

• Use odd clocks between the Pulser, the 5-step sequencer and the random: the combinations do not repeat and lively patterns emerge.
• Slow Function Generators in Loop with some Rand L on the timbre and the gate: organic evolution without automation.
• The Inverter doubles your ideas: the same sequence straight on one oscillator and inverted on the other creates mirrored counterpoint.

Velocity and expression

• Velocity has no effect until you patch it: connect it to the CV of Gate 1 or to the Timbre CV for natural dynamics.

Common mistakes

• Too much modulation on everything: the sound becomes chaos. Add one modulation at a time.
• Pre-amp feedback without volume control: sudden peaks.
• 4-voice polyphony with heavy generative patches: high CPU and cut-off voices; for drones and sequences use 1 voice.

Presets to recreate

In genres and records

• Experimental and avant-garde electronic music: the first Buchla modular system was born in 1963 from a commission by the San Francisco Tape Music Center to Ramon Sender and Morton Subotnick; Subotnick made Silver Apples of the Moon with a Buchla 100 series, the same unit used for Buffy Sainte-Marie's Illuminations. Suzanne Ciani worked for Buchla and Associates and built her career on a Buchla 200.
• Contemporary ambient and new age: Kaitlyn Aurelia Smith uses the Buchla 100 and the Music Easel as her main instruments.
• Generative ambient and drone: 3–5 step sequences, random voltages, timbres that change by themselves.
• IDM and glitch: bleeps, west-coast percussion, random modulations.
• Soundtracks and documentaries: organic and metallic textures.
• Experimental and minimal techno: percussion with the Lo Pass Gate.
• Contemporary modular electronics: the west-coast language (wavefolding, lo pass gate) is at the root of many modern modules.
• Experimental hip hop and beat music: textures and bleeps.
• Electronic pop and indie: timbral touches and sound design.
• Video game music and sound design.