AT HARVARD

"Quadrivium," a consort of early music, directed by Marleen Montgomery, will perform in the Thursday Noon Recital Series, Busch-Reisinger Museum, today at 12:15 p.m. Free.

Tim Chamberlain, flute, and Michael Dewert, piano play works of Telemann, Handel and Bach. Adams House Lower Common Room, Friday at 8:30 p.m. Free.

Pianist Phyllis Moss plays Ravel and Debussy pieces in a concert in Kirkland House JCR. Friday at 8:30 p.m. Free.

The second Bach Society Orchestraconcert of the season is this Saturday, featuring Bach's Brandenburg No. 2, Mahler's Kindertotenlieder, and Haydn's Symphony No. 104 "London." The Mahler work will be conducted by Peter Lurye. Sanders Theatre at 8:30 p.m. Tickets are available at the door.

Tamara Mitchell, soprano, performs vocal works this Sunday at 8:30 p.m. in Kirkland JCR. Free.

IN BOSTON

Roger Voisin conducts the Boston University Brass Ensemble in works of Purcell, Broiles, Bozza, Read, Gay and Lebow. 855 Commonwealth Ave, Thursday at 8 p.m. Call 353-3345 for additional information.

Brahms' Symphony No. 1 in C Minor is the feature work this Friday in a performance by the Boston University Symphony Orchestra. The conductor is Joseph Silverstein. 855 Comm Ave at 8 p.m.

The BU Trombone Ensemble presents seasonal brass music including 16th century, contemporary and jazz works, conducted by Ronald Barron. 855 Comm Ave Monday at 8 p.m.

Also on Monday, a program of contemporary songs at BU. Guest artist Margarita Scack, soprano, sings works of Stelarc, Beurle, Copelent and Cage. Jacob Sleeper Hall, 871 Comm Ave. The recital begins at 8 p.m. For information, call 353-3345.

The Museum of Fine Arts presents the second in its series of harpsichord lectures on Tuesday. The subject will be Virginals by Johannes Ruckers, Antwerp 1620. John Gibbons, harpsichordist to the Musical Instruments Collection of the MFA, is the lecturer. Call 267-9300, ext. 340, for more information.