New York Avenue Presbyterian Church offers an oasis for downtown office workers with its Tuesday noontime concert series. "We are not masters," says tenor Henri Lemmers, who will perform this Tuesday in the sanctuary. "We play from a 'heartilistic viewpoint.' "

Lemmers, who has peformed both nationally and at the Kennedy Center, describes his talent as "a large wild voice and a very soft voice." He will exercise these qualities in works from Beethoven, Schubert and Verdi, accompanied by pianist Mata Daramy.

The last concert of the series, on March 18, will feature pianist Neil Tilkens, who has played at the Phillips and Renwick Galleries and teaches music history at George Washington University. His works will include Bach's Toccata in E minor and Manuel de Falla's "Quatra Pieces Espanoles."

-- Jean Cavanaugh SPACE IS THE SPARK Meriam Rosen, director of the dance group Improvisations Unlimited, enjoys working in "unusual, nontheater spaces. It's a personal interest of mine," Rosen says. "I love how space gets transformed when used in an unordinary way."

She will have a chance to transform the atrium of the Metro East Business Community office complex into a stage when the group performs there March 13 as part of the Prince George's Arts Council's "Arts in the Marketplace" series.

Rosen described the dance as "movement improvisation. What we'll be doing there is much more 'sets,' which are comparable to what jazz musicians do. We start with a theme and then improvise around it."

The "Arts in the Marketplace" series has presented a performance in the Metro East complex the second Thursday of every month for more than two years, says Peg Stone of the Prince George's Arts Council. The series, sponsored by Rouse & Associates, the building's developers, is part of a campaign to "build a community in the office environment," Stone says.

"When this building was built, it was built around a performance space. I think that is unusual and unique in the county."

The concert begins at 12:15 p.m. and is free of charge.