Working blues bands- as in the kind blowing three or four sets a night in street corner bars- often gravitate towards instrumentals as the night wears on, whether playing to the patrons’ mood or their own, looking to lay back or to get some rocks off.  Harmonica player Richard Rosenblatt and crew (a foursome, to be clear) capture this atmosphere in a splendidly low-key, all-original and highly tuneful manner.  Down tempo and upbeat fare each take their turn with Mr. Rosenblatt and guitarist Paul Lenart serving up consistently solid solo work. The slow selections “Sleepless” and “Down and Dirty”, in particular, evoke a particularly appealing after-hours mood.