Working in an all-acoustic quartet at the One Step Down last night, saxophonist Bill Evans assumed a far different identity from the one he has had the past year with Miles Davis' electronics-dominated group. Evans was playing with premier bassist Charlie Haden and two excellent Washington musicians, pianist Marc Cohen and drummer Mike Smith. An opening set of several originals (jointly by Evans and Haden apparently) and Davis' "Tune Up" convinced one that here is a gifted young creator in the contemporary idiom.

There is a mixture in Evans of the free-school and straight-ahead playing that makes for interesting and moving listening. On the Davis piece he offered short one-bar phrases with intervals between them until he let the swift pace catch him up and he flew with it. That same piece was brought down to a funereal gait by Haden's solo, which was a solemn oratorio of emotion-wresting beauty and awesome technique.

Evans played tenor for several numbers and utilized sonorities that were fairly conventional. But when he turned to the soprano his tone took on the Middle Eastern keening of the modern school on a number that seemed to draw from spirituals and march music and had Haden buzzing on his bowed bass in the background.

The quartet performs again this evening.