Analog Synthesizer

A synthesizer is described as an electronic instrument, at times accessible via a keyboard that creates and amalgamates waveforms used pre-stored acoustic instrumental samples, known as wavetable synthesis, or FM synthesis. An analog synthesizer, otherwise known as analogue synthesizer or simply ‘analog synth’ is a synthesizer that utilizes analog computer techniques and analog circuits to electronically generate sound.

Analog synthesizers date back to the 20s and 30s when instruments such as Trautonium came into being. This instrument in particular was constructed using a range of electro-mechanical and thermionic valve (vacuum-tube) technologies. As time moved on and technology advanced, analog synthesizers were built with a range of operational amplifier integrated circuits, together with potentiometer with the hope of adjusting and enhancing the traits of sound produced.

Sound modification is further enhanced by the use of low-pass and high-pass filters. Initially, analog synthesizers such as the Moog utilized a variety of independent electronic modules which were interconnected to each other by the use of patch cables but as time progressed, all were integrated into a single unit, as is evidenced in the Minimoog. This got rid of patch cords and paved way for integrated signal routing systems.

This is because patch cords were highly priced and could easily get damaged creating hard-to-find irregular faults, which made complicated patches not only time-consuming but also hard to re-create. This therefore saw the introduction of analog synthesizers that used the same building blocks but were in single units.

Originally, analog synthesizers used technology borrowed from electronic laboratory test equipment and analog computers. They were basically ‘modular’ analog synthesizers made up of independent electronic models connected into a patchbay using patch cables. These modules included voltage-controlled filters, voltage-controlled oscillators, and voltage-controlled amplifiers. Also, they used low-frequency oscillators, envelop generators, and ring modulators. It wasn’t uncommon to also find some analog synthesizers with effects devices such as reverb units, sound mixers, or sequencers, all which amplified and enhanced the quality of sound produced.

Due to the complexity of generating notes using analog synthesis, majority of analog synthesizers largely remain monophonic. Their polyphonic counterparts feature very limited polyphony, basically supporting only four voices. During the 70s when companies looked to design advanced analog synthesizers, innovative technology included a built-in keyboard that lacked the modular design but with the analog circuits, with interconnect able switches put in a very simplified manner known as ‘normalization’. Even though normalization was less flexible than a typical modular design, the design made an analog synthesizer user-friendly and ultra portable.

The design of the Minimoog in particular influenced the manufacturing of almost all subsequent analog synthesizers featuring an integrated keyboard, wheel, pitch wheel and modulation, and a VCO->VCF->VCA signal flow, all which are useful in the quality of sound produced by today’s analog synthesizers.

Since most of these modules processed input sound signals, analog synthesizers could therefore function as sound-generating systems and sound-processing systems. Worth mentioning is the vocoder, a specialized type of analog synthesizer whose original concept and design was based on equipment made for speech synthesis. The main role of Vocoders is to produce a sound that imitates a musical instrument singing or talking.