Sound Synthesis in Music Technology

Synthesis in the production of music used to describe the process of creating a sound using electronic hardware or software; and this technique is always used in synthesisers. This was created because as time has evolved, musicians have wanted new sounds that acoustic instruments cannot produce; so they turned to synths to help create more sounds. There are three main types of synthesis that I'm going to go into detail about, however there are many more just as important but not as frequently used.

Subtractive Synthesis

Subtractive synthesis is the dominant form of synthesis, due to how popular it was in the 60's and 70's, and was the basis for the analogue synthesisers such as the Yamaha CS-80 and the Moog MiniMoog. This process involves taking a pre-existing sound and subtracting aspects of that sound away to create a completely new tone/sound. The sound would need to be rich in harmonics so that the producer could subtract different tones and pitches. An example of this within a synthesiser would be to get a pre existing electronic sound, assuming its a smooth sine wave sound, take away that sine sound and use ADSR filter envelopes to alter that sound to your liking.

This method would be key for those musicians who enjoy the vintage synth tones of the 60's, 70's and 80's, as synths back then were very simplistic but did the job perfectly, which is why so many older synthesisers continue to succeed today. This for many musicians is the starting form of synthesis they'll use as its very simple to do and you don't need to know too much about the components of a synthesiser such as envelopes, filters and oscillators. The Roland GAIA is a fantastic synth to learn this form of synthesis on as it's almost completely dedicated to subtractive synthesis.

FM Synthesis (Frequency Modulation)

FM synthesis is the process of taking a waveform, such as a sine, sawtooth, square or triangle wave, and modulating it with a modulator; the result of this is a far more sophisticated and complex waveform. The professional terms for each wave is the carrier and the operator, with the operator being the modulated waveform. You can modulate one waveform over and over again until you have the most complex waveform in the world that could sound amazing or horrible.

This was one of the first forms of synthesis to be introduced into music production, but strangely it never came into the mainstream until the 1980's, where its use was more or less wasted after the era of Disco was dying out. The best part about this synth and the most appealing to musicians is the fact that the sound you like can be incredibly complex, which is why everyone loved the sounds this synth produced in the 80's; no one had heard anything like it before. It first appeared in the iconic synthesiser, the Yamaha DX7, but you can find it today in on of Native's synth the FM8, or Logic and Komplete.

PCM Based Synthesis (Pulse Code Modulation)

PCM or Pulse Code Modulation is a form of synthesis whereby the producer uses samples as their primary source of sound. This technique wouldn't be used in electronic music necessarily, as its better at taking an acoustic sample and making it sound very authentic. Summed up a sample is played back at a faster or slower speed to alter its pitch, which has a corresponding impact on the sample playback time.

Sounds are constructed using multiple layers of samples, for example a piano or guitar sample all with different velocities; and these can be used to create complex and distinguishable sounds. If you're looking for a synth that uses PCM Synthesis, then expect to find a wide variety of samples, all doing the same thing with slight differences to give the producer a wide range of frequencies and samples to play with. Native's instrument Komplete would be a good synth to start with.