There were no flutes, guitars or backup singers on stage at the Merriweather Post Pavilion last night. Nevertheless, Al Jarreau produced a flute solo, several guitar solos and backup to his own lead vocals with nothing but his voice. He put on a dazzling display of vocal technique, imitating everything from the malfunctioning sound system to Brazilian congas to Count Basie vocalists.

Jarreau's technique involved far more than mere imitation, however. He improvised freely as he cramped frustrated lyrics into staccato bursts and expanded joyful lyrics into yelping yodels and skittering scat syllables.

Unfortunately Jarreau's technique often overwhelmed his humdrum original songs. He only realized his real potential when he took on substantial jazz tunes like Chick Corea's "Spain" or his tribute to Basie.

Alto-saxophonist David Sanborn displayed a much narrower range of technique in the opening set. His phrases were short and underdeveloped, but boasted his singing tone and a melodic hook. He stayed away from jazz improvisation and stuck to sophisticated pop instrumentals. On "Anything You Want," Sanborn's sax made quick leaps to the foreground to restate the theme before receding into the background of funky dance rhythms churned up by his quintet.