Moog Modular Synthesizer - Basics

Basics

The Moog modular system consists of a number of various modules mounted in a cabinet. Each module performs a specific signal-generating or -modifying function. These modules offered unprecedented control over creating sounds by allowing a user to modify primary sound waveforms (sine waves, square waves and other waveforms provided by voltage controlled oscillators or VCO) with amplitude modulators (voltage controlled amplifiers or VCA) and spectral modulators (voltage controlled filters (VCF) or fixed filter banks) and other modifiers. Envelope generators provided further control by modulating the attack, decay, sustain and release (ADSR) parameters of the VCAs, VCFs and other modules. The modules are patched together with patch cords with ¼i-inch mono plugs. The patch cords and module parameter knobs could be adjusted in countless ways to create a nearly infinite number of sounds. The final sound was heard ('triggered') from the system by pressing a key on an attached keyboard or pressing on the ribbon controller.

The Moog modular synthesizer offered musicians a revolutionary new way to produce sound when it was released in the 1960s. It was originally intended for use in recording studios and universities and was not intended for (or widely embraced by) musicians for use in live performance. The analog electronics of the system often made sound generation unreliable and unpredictable during live performances. For example, the VCOs were notorious for their inability to hold a fixed frequency for any extended period of time and would often change pitch and go out of tune, especially in hot or damp environments. Additionally, modular sounds could not be programmed and stored for retrieval due to the instrument's analog nature. Changing sounds on the system was a time-consuming task requiring the physical re-routing of numerous patch cords and manual knob adjustments.

Another common problem is the Moog's incompatibility with the gate/trigger voltage used in most other synthesizers of the time. Moog equipment used a high-state logic called S-trig, which maintained at +8-10 volts until the trigger was sent, dropping the voltage to 0, the opposite of what was commonly used by other manufacturers. In addition to this incompatibility, if a certain patch used an extensive amount of triggering connections, each module would cause a voltage drop sending the logic over into low-state and firing the S-trigger. In spite of all its shortcomings, a few artists (including Emerson, Lake & Palmer, Klaus Schulze, Tangerine Dream, and Hideki Matsutake with the Yellow Magic Orchestra) successfully toured with Moog modular systems.