Most common form. Start with a harmonically rich sound (the oscillator) then subtract harmonics with a filter and volume with an envelope. You can think of it like sculpting.
Start with a pure sine wave, called a carrier, and modulate it with another (inaudible) sine wave, called the modulator. This modulation creates harmonics in the audible carrier wave. Combinations of multiple carriers and modulators, called algorithms, create more complex sounds.
Involves recording (or sampling) a sound into digital memory.
At its heart are digital oscillators that use wavetables, or groupings of single-cycle waveforms. Playback can move laterally across the waveforms, resulting in unique expressions of movement and sonic change. This movement can be controlled with envelopes, much like volume can be controlled in subtractive synths.
In contrast to wavetable synthesis, which interpolates between waveforms stacked side by side, vector synthesis gives the user control over the volume balance of four sampled waveforms arranged as if occupying four corners of a two-dimensional plane, with a joystick to crossfade between them.
Where subtractive synthesis involves starting with harmonically rich sounds and paring back, additive synthesis is the opposite, using a number of harmonic partials of sine waves that, when added together (hence the name), create harmonically rich sounds.
Spectral synthesis is a kind of resynthesis that transforms a sound into a number of spectral bins, where each “bin” is a representation of its frequencies. The sound’s noise content is also represented. This content is then displayed on a spectrogram, which represents the frequencies in terms of pitch as well as density. This allows for unique and targeted shaping of sound at the frequency level.
Where basic subtractive synthesis can mimic the sound of physical acoustic instruments, physical modeling goes one further and digitally recreates the processes whereby a sound is made. This involves using digital signal processing (DSP) to recreate the various properties that make up the sound, usually the exciter (such as a bow on a stringed instrument or breath for a woodwind), the resonant body of the instrument, and often the properties from which it is made (wood, metal, etc.).
A kind of sample synthesis but one that acts almost microscopically on the sample, breaking it down into tiny parts, or grains, and allowing playback to jump around to different grains in the sample. Grain size, volume, position, etc., can be manipulated, resulting in new sounds.
Interesting stuff here! I have not done all that much synthesizing work (outside of undergrad college Electronic Music Studio classes) and it’s always been from a utilitarian perspective. I’ll look more into these!