Sonic Pi's :tb303 synth emulates the Roland TB-303 with a dedicated cutoff envelope and resonance

The :tb303 synth models the core signal path of the Roland TB-303: oscillator (wave: 0=saw, 1=pulse, 2=tri) through a resonant low-pass filter into the amplitude envelope. The filter has its own envelope opts (cutoff_attack:, cutoff_release:) in addition to the standard ADSR. High res: values (near 1.0) cause filter self-oscillation, producing the characteristic acid squelch. High resonance plus sweeping cutoff is the defining acid bass technique.

Examples

use_synth :tb303 live_loop :acid do play :e1, cutoff: 100, res: 0.9, wave: 0, release: 0.125 sleep 0.125 end

Assessment

Build an acid bass line using :tb303 with cutoff_attack: 4 and cutoff_release: 4. Explain what happens audibly at res: 0.999.