C'est What?, a New York-based quintet, answered the query explicit in its name with an opening set at Blues Alley last night. The music was, quite simply, an informed and blended eclecticism, rather than the all too common scissors-and-paste fusion. Richly textured and harmonically sophisticated, it was drawn from sources that included jazz, blues and folk music.

The two guitars, twelve string and classical respectively, of Matt Balitsaris and John Wunsch wove a complex of melody and countermelody that at times was nearly as dense as harpsichords in duo. Balitsaris switched to electric guitar on several pieces for some wailing, blues-drenched horn lines.

Vibraphonist Jeff Berman has put together an impressive four-mallet attack that is part pianistic, part hard-driving Lionel Hampton swing. He also contributed some special percussion effects, of which his use of a violin bow on a Chinese gong was especially notable. Chip White's drumming was nicely integrated into the ensemble sound and the electric bass of David Ames Snyder was tasteful and restrained.

The one negative observation that comes to mind is the group's total reliance on the members' own compositions. Sometimes a sameness crept into their sound. But this is a very original group and one to watch.