CLASSICALLY SPEAKING, this is Cleveland weekend in Washington. The Cleveland Orchestra plays Mussorgsky, Schumann and Philip Glass, Sunday night in the Kennedy Center Concert Hall while the Cleveland Quartet plays an all- Beethoven program Friday night at the Corcoran Gallery and Saturday night at the University of Maryland.

Tickets for the orchestra (one of America's best) were almost sold out a few weeks ago; and even with the Redskins in the Superbowl, seats are still limited.

Whatever else it may or may not have, Cleveland's eponymous classical music ensembles are among the finest in the United States. The orchestra's most recent recording is a superbly played, slightly understated reading of Tchaikovsky's Sixth Symphony, conducted by Christoph von Dohnanyi and beautifully engineered.

The quartet is joined by pianist Emanuel Ax for one of the finest chamber music recordings in recent memory: Schumann's Piano Quintet, Op. 44 and his Piano Quartet, Op. 47. These works are played with ideal technical fluency, emotional involvement and feeling of dialogue among the players. CLEVELAND ORCHESTRA --

"Tchaikovsky's Sixth Symphony" (Telarc CD-80130). Performing Sunday at the Kennedy Center.

CLEVELAND QUARTET --

"Schumann's Piano Quintet, Op.44 and Piano Quartet, Op.47" (RCA 6498-2-RC). Performing Friday at the Corcoran Gallery, Saturday at the University of Maryland.