Audio: synth (0:12)

Figure: synth

synth plays four synthetic sounds in succession: a Moog synthesiser, a theremin, a crystal synth and a chiffer lead synth. The Moog and theremin are hard synths, the crystal and chiffer lead are soft synths. The synth figure shows the composite waveform.

A synthesiser or hard synth is a physical musical instrument that contains electronic circuits or computer software. A software synthesiser or soft synth is computer software.

There are a plethora of names for synths. A hard synth is also called an analogue synthesiser and an electronic musical instrument. A soft synth is also called a digital synthesiser and a virtual instrument.

Hard synths come in all sorts of guises. The Moog synthesiser is a famous hard synth. It was first developed in the 1960s and uses voltage-controlled electronic circuits to generate a huge variety of synthetic sounds. The theremin is an even more venerable hard synth. Developed in the 1920s it achieves its unique quivering sound by using hand movements to generate electronic signals in two antennas. These signals are used to vary the frequency and amplitude of a sine wave. There are hundreds of other hard synths in existence. This list of electronic instruments and this list of classic synthesisers will provide hours of nostalgia for hard synth buffs.

A soft synth is not a physical instrument, it is computer software designed to generate sound. It does not matter where the software resides. It could be inside a hard synth, it could be in a desktop computer, a laptop computer, a tablet or a mobile phone, or it could be in a cloud on the internet. There are thousands of soft synths. The chiffer lead and crystal synths in synth are both MIDI instruments, a common type of soft synth.

The distinction between hard and soft synths is increasingly blurred. There is also a negligible difference between a computer and a synth. The terms, computer and synth, are used interchangeably throughout the guide to mean the same thing and cover both hardware and software.

Synth design is a thriving industry. There are a limitless number of sounds that can be created with a computer and making your own synth is one of the specialist and pleasurable aspects of music writing.