Musical Synthesis 101
2.6a Subtractive Synthesis
This is a simple subtractive synthesizer that utilizes a lowpass filter that is controlled by the ADSR or the attack, decay, sustain, and release. Each of these variables controls the gain of the synthesizer at a given time. The attack is engaged at the very beginning. A short attack will result in a pluck sound. Next the decay tells us how long it takes to go from the maximum gain to the sustained gain. The sustain level defines the gain at which the synthesizer will hold if a note is also help. Finally the release tell the synthesizer how long to modulate from the sustain to silence once the note is released.
Try using the keys on the screen, your keyboard, or a MIDI device to play the synthesizer. Make sure to click start!
The lowpass filter is responsible for filtering out the higher frequencies. You can control the frequency of its cutoff using the ‘Filter Frequency’ slider. Additionally, you can control how resonant the filter is by adjusting the ‘Filter Q’ slider. The ‘Envelope’ slider controls how much the ADSR effects the filter cutoff.