By Richard Dyer, Globe Staff, 05/05/99

BOSTON POPS ESPLANADE ORCHESTRA
Keith Lockhart, conductor
At: Symphony Hall, May 4, 1999

''The only place where they should put music in categories,'' said Al Jarreau, praising the Boston Pops, ''is in the record store.''

Jarreau was one of the two guest stars last night at the opening of the Pops season. Paradoxically, the Boston Pops itself was not on hand because the Boston Symphony is on tour in Japan and China. Sitting in were the regular alternates of the freelance Boston Pops Esplanade Orchestra, an ensemble which may lack the tonal sheen of its counterpart, but offers spiffy solo work, spirited ensemble, and a high energy level.

The first part of the program was designed to show off the orchestra in Bernstein's overture to ''Candide,'' the intermezzo from Mascagni's ''Cavalleria rusticana'' (''a beautiful interlude,'' conductor Keith Lockhart said, ''in a tawdry story''), and Rimsky-Korsakov's ''Capriccio espagnol,'' which featured virtuoso solo playing from concertmaster Joseph Scheer, flutist Marianne Gedigian, clarinetist Ian Greitzer, and others.

Lockhart has continued Arthur Fiedler's tradition of introducing interesting young musicians, particularly those with local roots. The 19-year-old violinist Ayano Ninomiya, who has lived and studied in Boston for 18 years, was distinctly superior to some other violinists who have used Opening Night at the Pops as a stepping stone to publicity. Ninomiya's choice was the Glazunov Concerto, a rarely played piece that makes an attractive alternative to some overexposed works from the romantic repertory. She played it with taste, skill, and feeling; while others strive for volume and pulsation, Ninomiya concentrates on quality and coloration of tone. She has plenty of assurance and command, but instead of assaulting the listener, she quietly asks the listener to come to her, and the public did. Her superbly executed solo cadenza did have to compete with an unacceptably high level of hall noise emanating from the lights or the ventilation system.

The decor in the hall this season is understated -- a bit of glitter on the walls, some colored lights, projections of 16th-notes and clefs. Last night there was an experimental new sound system for Jarreau that represented a significant improvement over the distortion that used to blast out from the great golden monster suspended over the stage, although the volume was considerably in excess of what was actually necessary.

Jarreau, a one-man band, brought along his usual ensemble of Gil Goldstein (piano and arranger), Freddie Ravel (electric keyboards), Chris Walker (bass), and Jota Morelli (drums), and Lockhart and the Esplanade Orchestra steeplechased right after him, providing an opulent backdrop for his vocal choreography and musical body-language. Jarreau performed some of his greatest hits, including ''In My Mind,'' ''After All,'' ''Take Five,'' and the new ''Tomorrow, Today,'' but basically his entire set was one continuous number -- this man turns everything into rhythm and music. He sang most of his introductions, patter and commentary, his voice ricocheting across 2 1/2 octaves in an astonishing variety of timbres. With his voice he mimicked instruments, and even Gregory Hines in full tap-dancing flight, and encouraged two-part inventions not only with his own band but with members of the orchestra. His manic humor is self-aware -- ''Can you imagine me on vodka?'' he asked -- and as Jarreau's exuberance clocked the evening into costly overtime, Lockhart brought the concert to a close by launching the orchestra into ''The Stars and Stripes Forever.'' The irrepresible Jarreau, far from being offended, added his riffs, and the piece sounded like an ode to joy.