Thanks, Soundquest. Yes, the bass was naturally played on the pedals, and the patch itself consisted of four oscillators of sawtooth and PWM tones tuned to 16' and 32' octaves, so it's very deep. Plus, it's polyphonic. The P'08 module is perfect for the purpose.
If the music seems a little different, that's because it's a composition, rather than an improvisation. When I do a synthesizer improvisation, I tend to drift near ambient electronica territory, which is never my intention. I like much better producing carefully designed compositions.