Using Feedback in Sound Design

One way to make a sound more alive is by using feedback loops at different stages. In a synthesizer or FX chain a loop will shape sound with a repeated frequency. The sound is referencing its own signal from another part of the system. Ultimately the sound will hit a maximum resonant frequency or amplitude. If the system is well designed, it won't blow your speakers! If its digital, the worst that can happen is clipping. You can adjust levels to create the most interesting effect without going overboard. There are ways to control the sound so its not just a constant overload which I also mention below.

1. Feedback Knobs - This is found on chorus, phasers, delay etc.
2. Dynamic Envelopes - Like a compressor, or dynamic filter, these reference the amplitude of the input to make the sound come alive. Found on V-synth, lots of software FX filters.
3. Feedback Oscillator or Loop chain built into a synth - This is found on Dave Smith's designs and also V-synth. This can create circuit overload and clipping sounds.
4. Reverb - Reverbs are a type of feedback. The sound is repeated back to you and affected by time / resonance.

Step Two: How to control and shape the feedback.

Try amplitude modulation or randomization before the inputs. The goal is to find some kind of balance and interesting use of the feedback. The end result is a new sound with some cool time effects. All of the modulation and self referencing will make the sound come alive.

WARNING, this is what happens when you feedback a Roland supersaw wave.