BassMatrix is a Roland TB-303 bassline emulation.
This is a synth that trying to sound like the classic TB-303 bassline synth and provide a simple interface to program the patterns.
You can use MIDI PLAY to play any note and you can use KEY SYNC to get an arpeggio like syntesizer. Normaly you want to use HOST SYNC to sync with your DAW and change the patterns with MIDI notes.
here is also INT. SYNC that is useful when you play the synth standalone (there is a loop size knob for this purpose so you can automatically change patterns in live mode).