A basic guitar synthesiser using the toybox Free Pack
A basic guitar synthesiser that tracks the envelope and the pitch of the input signal and controls a simple single-oscillator synth.
Pitch and gate signals are extracted from the input signal by using a pitch follower and 2 envelope follower blocks. Before they are used by the synth these pitch and gate signals are cleaned-up a little to avoid any mis-tracking of the pitch signals.
How it works:
1. The incoming audio is compressed using a compressor block to even out the dynamics (adjust the OUTPUT control of the compressor to set the sensitivity of the Guitar Synth’s tracker).
2. The LEVEL of the input signal is then tracked by 2 envelope followers with identical settings. One of the envelope followers has a very short delay applied to it’s input that avoids the initial transient of the incoming guitar note (an area where the pitch tracking will be less reliable). This will add a small latency to the synth, adjust the ‘DELAY’ setting to get a good balance of latency vs clean attack sound.
3. The output of the direct and delayed envelope followers is then combined through an AND function (The AND function will only output a gate when envelope 1 AND envelope 2 are sending out a gate signal).
4. The PITCH of the input signal is tracked by a pitch follower, the resulting pitch signal is sent to a mixer. The ‘mix mode’ is set to HOLD, in this mode the signal at input 1 is passed when the signal at input 2 of the mixer is positive and is held at it’s current value when input 2 is zero or negative. Our gate signal from the envelope followers is sent to input 2 to control the pitch signal, but first it is inverted so that the pitch is only passed when the gate is open and held when the gate is closed, this stops the pitch from ‘chattering’ when the guitar strings are dampened.
5. The cleaned up pitch signal is sent to the oscillators pitch input and the gate signal is sent to the ‘Volume Envelope’.
6. A 3rd envelope power (‘Filter Mod’) is used to open and close a filter altering the timbre of the synth and then the synth's output is passed through a simple chorus effect comprised of a ‘Short Delay’ block modulated by an LFO.
toybox Free Pack