Done more work with this combination this afternoon. Sonic Pi sends midi to the Matrix Brute and also a clock to sync its arpeggiator. The Arpeggiator sends a separate midi stream to Live where it plays pizzicato stringed instruments. Also fed to live is the audio output from MatrixBrute playing a selected preset. The two channels are mixed in Live, but Sonic Pi controls a crossfade between them via OSC messages, the resultant Live audio output is fed back to Sonic Pi as a live_audio input where some reverb is applied. It gets quite hairy to cable and keep track of what does what, but is fun to do.