Derek Trucks was born to jam. He’s been so good for so long, it can, at times, be hard to hear the progress he’s making as an artist. But we heard it on Friday night at the Trustees Theater in Savannah. I have to admit, when he first changed his lineup, sending bluesman Bill McKay packing, I was aprehensive. Now the clarity of Derek’s vision is plain to see. With the addition of Kofi Burbridge on keys, flute and vocals and Mike Mattison on lead vocals, DTB is the premier jazz/soul/funk/Latin act on the scene today. The musicianship of the five players is simply at a higher level than one normally encounters, even in bands that can be called great. The venue was a tad formal for my tastes. Any place that discourages dancing has to be questioned. But even on my ass, the spiritual sounds of DTB worked their magic.