DJW Audio has introduced a free, open-source bass line synthesizer and step sequencer inspired by the TB-303 Bass Line synth from Roland.
DW-303 models the oscillator, filter, envelopes and VCA stage by stage from the original circuit schematic. The models were fitted against hardware measurements, with attention to the interaction between resonance, envelope modulation, accent and slide.
The instrument offers saw and square waveforms, a resonant ladder filter, and front-panel controls for tuning, cutoff, resonance, envelope modulation, decay and accent. Full circuit and Economy quality modes are available.
Its 16-step sequencer retains separate pitch and time entry, with notes, ties, rests, accents and slides. There are 64 patterns across four groups and seven tracks for chaining patterns into arrangements. Factory patterns are included, so users can start playback immediately.
The sequencer can follow the DAW’s tempo and transport, run from its internal clock, or synchronize to MIDI clock. DW-303 also accepts MIDI notes, with last-note priority, slides between overlapping notes, and velocity-triggered accents. Plug-in sessions retain pattern memory.
Version 0.1.0 is available for Windows, macOS and Linux, as a plugin (VST3, AU, AAX, CLAP and LV2) and a standalone application. No license key or activation required.