Franz Xavier Wolfgang Mozart was born in 1791, only a few months before his father, Wolfgang Amadeus, died. His mother Constanze discouraged the boy from a career in music, but the boy went ahead and studied with an acquaintance of his father, Antonio Salieri. Although the younger Mozart eventually became a pianist, conductor and composer, his music is little known today. Surely at least its provenance would encourage investigation. And the Cantilena Chamber Players satisfied our curiosity at the Hirshhorn Museum last night with the local premiere of F.X.W. Mozart's Piano Quartet in G Minor, Op. 1.

The first of its three movements rides the strings with grace and excitement, its long line contrasting nicely with the Adagio's intermittently short melodies. The finale is a set of variations on a theme that is a dead ringer for the final scene of Rossini's "Tancredi," decorated without surprise or offense. The work is light, and frankly its 30 minutes seemed much longer. The Cantilena's sound was not homogeneous, but it was well balanced, with Frank Glazer's intense pianism making up for a scarcity of elegance in the ensemble. And the performance, like the score, was seldom less than charming.

Not quite so charming was Aaron Copland's 1950 Piano Quartet. The players were fine, except for violinist Edna Mitchell's militantly flat playing. But the work is hard to love. The musical fabric is often colorful. Like the conversation of shallow acquaintance, the score recalled many things but left few memories as it passed.

The program closed with Gabriel Faure''s beautiful Piano Quartet No. 1 in C Minor.