Synthesist Joe Evans shared this look at additive synthesis and how it compares to the subtractive synthesis approach.
Additive synthesis is an approach to shaping sound based on the idea of adding together sine wave partials to create more complex timbres. Additive synthesis historically has been less practical with hardware synths than subtractive synthesis, because of the need to precisely control the amplitude over time of potentially dozens of oscillators. Software has made additive synthesis more practical, because you can have unlimited numbers of oscillators and control their amplitude over time precisely.
In the video, Evans uses AIR’s Loom II to demonstrate additive synthesis concepts.