(compMus1) Intro to Analog Synthesis

Just an outline of highlights from today’s lecture – look at the readings for more in-depth reference.

Analog Synthesis and the Classical Electronic Studio General

•  Time period: 1950s – early 80s
• Analog synthesis: generates/modifies electrical signals that fluctuate in an analogous (similar) manner to air pressure fluctuations.
• Voltage Control
• Modular Synthesis

Categories of Equipment in the Classical Studio

• Sound Producing: oscillators, noise generators.
• Sound Processing: envelope generators, filters, ring modulators, reverb units.
• Controllers: sequencers and keyboards
• Sound Storage: audio tape machines

Another way of classifying just the modules usually found on an analog synth:

• Generators
• Modifiers

With generators including all of the sound producing category above plus envelope generators (and low-frequency oscillators), and modifiers referring to the sound processing category.

Oscillators

Oscillators produce periodic fluctuating electrical signals at audio-rate frequencies. The fluctuating signals were usually one of four elementary patterns (called waveforms): sine, triangle, pulse (square is one type), and sawtooth. Read to know the spectra information (and relative amplitudes).

Noise Generators

Noise Generators produce randomly fluctuating electrical signals that contain all frequencies. Know the difference between white noise and pink noise.

Voltage Control

Voltage Control is an important concept/feature of analog synthesis. Since generators produced electrical signals of varying voltages, the output of generator modules could be controlled by other  generators. (Also parameters of modifiers.) Oscillators usually responded to each additional volt by going up one octave in pitch. (1v/octave) Along with voltage control, the potentiometer (pot) is also important. The pot allowed for scaling voltages by way of manipulating a knob.

Envelope Generators

The envelope generator produces a unipolar signal that can control the parameters of other modules over time (a function generator). Unipolar signals only deviate from zero in one direction (or pole). Audio waveforms are typically bipolar, as they deviate in two directions from zero, positive and negative.