Moog and the Birth of Analog Synthesis — Composing Sound with Voltage

The leap to “synthesis”

Early electronic instruments (the theremin, the Hammond organ) and electric pianos were built around a fixed sound-generating method, each producing “a particular sound.” But in the 1960s, an entirely different idea emerged — break the elements of sound into separate building blocks, control them with voltage, and assemble sound from nothing. This is the synthesizer (a machine that synthesizes).

The Moog Modular (1964) — the invention of voltage control

Robert Moog (1934-2005) was an engineer who got his start selling theremin kits. In 1964, he unveiled a modular synthesizer built around Control Voltage (CV).

At its core was a unifying principle: “every parameter of sound is controlled by voltage”:

• VCO (Voltage-Controlled Oscillator) — voltage determines pitch. Each key on the keyboard produces a corresponding voltage (1V/oct)
• VCF (Voltage-Controlled Filter) — voltage carves away brightness (the amount of harmonic content)
• VCA (Voltage-Controlled Amplifier) — voltage determines volume
• EG (envelope) / LFO — voltage shapes change over time

By freely connecting these with patch cables, an infinite range of timbres became possible. The design philosophy that “voltage governs everything about sound” became the foundation of synthesizers for the half-century that followed.

Subtractive synthesis — shaping sound by removing harmonics

The fundamental sound-design method Moog established is subtractive synthesis:

1. The oscillator generates a harmonically rich waveform (sawtooth, square wave, etc.)
2. The filter removes unwanted harmonics (determining brightness)
3. The amplifier shapes the volume over time (attack, decay…)

It’s a sculptural technique — carving away what’s unneeded from raw material (a mass of harmonics) to reveal a shape. The opposite approach from the Hammond organ’s “additive” method (adding harmonics together), subtractive synthesis became the mainstream technique for shaping analog synth sound.

Switched-On Bach (1968) — a shock to the world

A single album made the synthesizer famous overnight. Wendy Carlos (then known as Walter Carlos) released ‘Switched-On Bach’ (1968).

• Bach performed entirely on a Moog Modular
• Since synthesizers of the era were monophonic (one note at a time), the album was a painstaking work built note by note through multitrack overdubbing
• It showed the classical world and the general public that “a synthesizer can make real music,” and won a Grammy Award

This shifted perception of the synthesizer from “a strange laboratory device” to “a tool for making music.” Follow-up works emerged around the world, including Isao Tomita’s Snowflakes Are Dancing (1974).

Moog vs. Buchla — two philosophies

Around the same time, on the West Coast, Don Buchla was developing his own synthesizer. The difference between the two symbolizes a fork in the philosophy of electronic instruments:

• Moog (East Coast) — attached a keyboard. Designed as “an instrument for performing existing music”
• Buchla (West Coast) — deliberately omitted the keyboard, using touch plates and sequencers instead. Designed as “a device for exploring new sounds”

By choosing the keyboard, Moog placed the synthesizer on the lineage of “electronic keyboard instruments,” setting it on a path toward mass popularity. Buchla’s philosophy, meanwhile, was carried forward into the later culture of modular and experimental music (Article 9).

The limits of size and cost

The Moog Modular changed music history, but it had practical barriers:

• Enormous size — a wall of patch panels. Fixed in a studio installation
• Expensive — out of reach for the average musician
• One note at a time — no chords possible
• Unstable pitch — voltage would drift with temperature, requiring frequent tuning

Turning this revolutionary power to “design sound” into an instrument anyone could use on stage — that was the next challenge. The next article traces how the answer, the Minimoog, turned the synthesizer into a portable instrument and carried it into rock, funk, and city pop.