Denny Zeitlin and George Marsh have electro-acoustic roots going back to the late sixties when they recorded and concertized together for a decade in the Denny Zeitlin Trio. In 2017, 50 years later, Sunnyside Records released “Expedition,” a duo album of critically acclaimed free improvisations. Zeitlin’s studio resembles Mission Control at Houston, with the multiple computers, monitors, controllers, and miles of cables. Open to all genres, with no pre-planning of any kind, George, playing drumset and percussion, and Denny, playing acoustic piano, plus 4 keyboards/synthesizers, launch into free-improvisation. The sound barrier that provides separation for recording makes it impossible for them to see each other. They rely on headphones and a musical rapport that seems telepathic. The performances have such structural integrity that people often think these “spontaneous compositions” must have been written out.