The McLean Choral Arts Society begins its fifth season Sunday night with a new music director, Thomas Beveridge, who hopes to raise the quality of performance of the 70-member singing group without changing its community flavor.

Beveridge, a George Mason University adjunct professor in voice studies, takes the position that "most everybody has a singing voice . . . . Proper singing has very little to do with music. It's a physical thing that you have to be trained to do." Beveridge is a veteran of the concert hall stage.

Beveridge does not hold auditions but will train his singers in rehearsal and then augment the talents of his chorus with high-caliber soloists.

Beveridge succeeds Gordon Carlson, who founded the organization in 1983. His career includes voice recitals at the major concert halls, about 400 original compositions, and study with Nadia Boulanger in the American Conservatory at Fontainebleau near Paris.

"I've sung in choruses all my life . . . . I'd like to try some of the things that I've seen work," he said.

In his first effort with the McLean ensemble, Beveridge has enlisted Norman Scribner, conductor of the Choral Arts Society of Washington, to play the organ in Haydn's oratorio "The Creation." Soprano Rosa Lamoreaux, tenor Richard Turner and bass-baritone Noel Jan Tyl -- just back from West Germany for a television performance of Kurt Weill's songs -- will be featured in Sunday's 8 p.m. concert at the Lewinsville Presbyterian Church. Season ticket holders will be welcome at a reception after the concert at the McLean home of state Sen. Clive L. DuVal 2d..

Russell Woollen will join the McLean Choral Arts Society for its Christmas concert Dec. 13 at Trinity United Methodist Church. Beveridge has prepared an interpretation of the Christmas segments of Handel's "Messiah" that calls for Woollen, the National Symphony Orchestra's keyboard artist for 24 years, to improvise extensively.

On Palm Sunday, March 27, the McLean singers will premiere Beveridge's "Stabat Mater," a work that Beveridge says draws heavily on musical ideas from Gregorian chants. Sacred music by Mozart and Schubert will complement Beveridge's composition. The final concert of the season will be an afternoon of operatic favorites on May 22.