Additive (+) and Subtractive (-) Synthesis
Sounds can be added together or subtracted from one another. Learn how new sounds can be made in this way.
Additive Synthesis
Additive Synthesis involves building complex sounds from simple components (adding them together). As we saw in Complex Soundwaves, sounds can be added together to make new and more complex sounds. The most pure and basic type of sound is a sine wave. But if we analyse more complex sounds we can observe that complex sounds are often made up of multiple sine waves.
Guitar string ‘pluck’ made of multiple sine wave components
Listening Challenge
Listen to the individual sine wave component on its own and then play the original guitar sound. Can you hear the individual sine wave as part of the original guitar sound? Listening to the sine wave on its own draws our ears attention to it and allows us to pick out this specific tone within the more complex sound of the original guitar pluck.
Activity
Start with a collection of simple sine wave sounds and use these to build more complex sounds, using the process of additive synthesis.
Subtractive Synthesis
Subtractive synthesis involves carving sounds out of complex sounds or Noise (taking sound energy away from a busy / noisy source). Noise sounds contain a randomised assortment of sound energy spread across the sound spectrum. By using filters we can carve sounds out of noise, much like a sculptor might carve a statue out of a block of marble.
Full band white noise.
Listening Challenge
Can you hear the filtered sound from within the original full band noise? Does this filtered sound remind you of anything? What does it sound like?
Activity
Load up Compose With Sounds and experiment with additive and subtractive synthesis.
Sound Cards and Additive Synthesis
Open a project with the sine wave sound card pack loaded. Combine these individual sine waves to make more complex sounds.
Filters and Subtractive Synthesis
Take some noise sounds and use the available filters to carve out new sounds. Noise Sound card Pack.
