Waveforms and Subtractive Synthesis

When using a synthesiser to create sound, fundamental waveforms are first created by layering sine waves generated through oscillators. These waveforms are Sine(containing only fundamental harmonics), Sawtooth (containing odd and even harmonics), Square (containing only odd harmonics) and Triangle(containing also only odd harmonics, which drop in amplitude proportionally to the frequency).

These waveforms used in a subtractive synthesiser will then have aspects subtracted away to mold the sound. This will be done typically through various types of filters and ADSR (envelope) where a number of parameters can be utilised, these include Attack, Decay, Sustain and Release. Of these, attack controls the amount of time it takes from the start of the sound to reach the peak amplitude, this then reduces with the decay parameter to what is set with the sustain level parameter (the other three being tone parameters), finally once the key is unpressed the release parameter determines how long until the signal’s level will remain. ADSR settings also contain a number of parameters which are within the four main elements, which mainly include the durations assigned by the user to each of the stages.

Filters which can be applied to alter sound through cutting away specific frequencies include high-pass filters, low-pass filters, notch filters which take out a portion of frequency from the middle of the audio spectrum, and band-pass filters which remove from the ends.

Linked is also the example demo session file for synthesis in the Ableton software :

https://drive.google.com/drive/folders/17WAq3Ih72_Qh0UtzHbpTnC_PPbBUfIlz?usp=sharing