Folk-Rock's Ethel Merman   

Joni Mitchell has in previous performances stood, flaxen-haired and frail, alone in the spotlight. On Tuesday at Avery Fisher Hall, however, she threw this sedate image aside as she crashed into her first song, backed by the L.A. Express group, a jazz-rock unit dominated by the tough saxophone (both tenor and soprano) of its leader, Tom Scott.

Later a largish string section materialized to take Miss Mitchell farther away from her earlier environs.

But the impact of the violins was somewhat lessened by sound problems.

This is not to say that Miss Mitchell has turned rocker - just that she has sewn her folkishness right onto a gutsier framework, sweet and sour working together.

Miss Mitchell remains earnest in approach, hightly serious, a singer of editorials for herself through which a tune may - or may not - be threaded. She is now including songs about being a star (which she is) and feeling guilty about the whole thing.

The Mitchell voice, seemingly delicate can still cut through the energetic arrangements of L.A. Express, making her folk-rock's Ethel Merman.