Soft spoken, innovative-even a little ahead of his time, trumpeter Russell Gunn is making headlines across the country with his fourth album in the series: Ethnomusicology Nominated twice for the Grammy, this series winds up with Volume Four, a live collection blending jazz, hip-hop, R&B and slipping in an Ira & George Gershwin tune, Summertime. If that isn’t broad enough, Gunn includes a Miles Davis number, Blue In Green. Mega talented Gunn, a true visionary, doesn’ …