Al Jarreau began by singing with Milwaukee R&B combos in the early 1960s; by the mid-’70s he was a rising jazz vocalist on the national stage. He has performed at the prestigious Montreux Jazz Festival many times since then, including the 1993 set released here. Jarreau’s vocal gymnastics may be difficult, but he never wanted to make difficult music. His jazz has always been smooth, poppy and on melody. For this Montreux concert, Jarreau chose the song he added to the list of contemporary standards, the jubilant “We’re in This Love Together,” along with such canonical numbers as “Summertime” (in a funky rendition) and a scat-happy “Try a Little Tenderness.”