A synthesizer is a kind of electronic musical instrument, or electronic device capable of producing or manipulating audio tones, such as musical notes, through audio signal processing. The term originates from the Greek word Syntithetai. One of the main features of synthesizers is that they work by manipulating electrical signals, which appear as sound when they are used to drive audio amplifiers. Music synthesizers sometimes include a keyboard, which remind us of certain traditional musical instruments.

There are three major kinds of synthesizers depending on the different features of synthesizers

Analog

Digital

Software

In addition there are synthesizers that rely upon combinations of those three kinds, known as hybrid synthesizers having a different set of features of synthesizers. Analog synthesizers were the first to be created and developed. After that, came the digital synthesizers. Both analog and digital synthesizers use the same kinds of synthesis methods. These methods are used especially for frequency modulation and phase modulation. Some of the methods are stated below

Subtractive synthesis

Additive synthesis

Frequency modulation synthesis

Phase distortion synthesis

Sample based synthesis

Sub harmonic synthesis

Granular synthesis

Wavetable synthesis

Early features of synthesizers include using the technology derived from electronic analog computers, laboratory test equipment, and early electronic musical instruments.

Brief features of Analog synthesizers

An analog synthesizer is a synthesizer that uses analog circuits and analog computer techniques to generate sound electronically. A very common point among the features of synthesizers of this kind is circuit component; it is the operational amplifier which is a kind of integrated circuit in most of the analog synthesizers. An analog synthesizer could be used both as a sound generating and sound processing system. A very specialized form of analog synthesizer was the analog vocoder, based on equipment developed for speech synthesis. Synthesizer modules found in early analog synthesizers included:

VCO or voltage controlled oscillators

VCF or voltage controlled filters

VCA or voltage controlled amplifiers

Envelope Generators

LFO or low frequency oscillators

Ring Modulators

Sequencers

Some facts about Digital synthesizers

As technology advanced into the digital domain, the new digital technology started coming up in their new designs. Analog synthesizers were mostly replaced by digital synthesizers and samplers over the early mid 1980s. Gradually the voltage controlled analog synthesizers circuits were replaced by microprocessor controlled digital circuits.

The digital synthesizers have advanced features of synthesizers. They have a completely different and advanced sound clarity, since their internal sounds are stored in memory as arrays of numbers. The first breed of digital synthesizers had a much more slick and clean design where the user could program the instrument using a menu driven operating system. One of the first real time polyphonic digital music synthesizers was the Coupland Digital Music Synthesizer.

Basic modules of synthesizers

Three most important modules shaping the features of synthesizers are

The Oscillators

A simple oscillator can create one or two basic waveforms. They are saw tooth wave and a square wave. These waveforms are very simple and completely artificial.

The Filters

A filter is an electronic circuit, which works by smoothing out the edges of the original waveform. Synthesizers use filters to vary the basic waveforms to some extent.

The Amplifiers

The amplifiers can raise, or lower the height of the waveform, thereby raising or lowering the volume of the sound. To control the volume of a sound in the synthesizer, the signal is passed through an amplifier circuit.

Conclusion

Synthesizers were developed in the early twentieth century. It has advanced remarkably in time and has attained a distinguishable position in the music industry. It has now become an indispensable part of every music concert.