The first time I heard the following complaint I thought perhaps it was the result of an isolated incident. This letter from an Arlington concertgoer, however, restates what I have heard frequently in recent months. Clearly some new troublesome habits are moving into our concerts. Love and music mix wonderfully, but there are ways and ways - hm?

"Could you occasionally remind people of no-no's at concerts, such as lovers shoulder-to-shoulder and head-to-head, blocking the view of people behind them; wearing of tinkle ornaments (bracelets); people bobbing their heads from side to side; annoying whispers; turning pages of programs and rustling the pages."

My own continuing reminder is that there is NO reason for talking or whispering while the music is being played. Nor for people, especially those who sit in box seat, to walk in and take their seats after the music has started. They should wait at the back until the music is over.

Next Monday night the third and final event - for this season - of the Handel Festival in the Kennedy Center is his gorgeous opera-oratorio, "Solomon." Some of the greatest music Handel ever thought of fills pages in this work. The singers will include Elinor Ross, Nancy Shade, Lorna Hayward, John Reardon, Grayson Hirst, Sung Sook Lee and John Ostendorf. Stephen Simon will conduct the Handel Festival Chorus and Orchestra. It should not be missed.

The Washington Brass Quintet will kick off the new series of free concerts called "Music At Noon," to be played at 12:15 p.m. in Western Presbyterian Church, 1908 H St. NW, on the four Thursdays beginning April 21. A project of the Washington Performing Arts Society, the new concerts are being funded by the Morris and Gwendolyn Cafritz Foundations. Four more are planned for the fall. The programs are to last around 45 minutes.

Aaron Rosand, one of the world's great violinists, will play a concert in Georgetown University's Gaston Hall at 8 p.m. Sunday. Rosand, who will be one of this week's soloists at the Romantic Festival in Indianapolis, is playing Sunday under the sponsorship of the Georgetown Symphony Orchestra. Tickets at the door. Reservations by called 625-3181.

George Manos, well-known Washington conductor and pianist and the founder and music director of the Kilarney Bach Festival, will conduct the National Symphony Chamber Orchestra at 8:30 p.m. Friday in the Kennedy Center. Irish mezzo Bernadette Greevy will sing Back's Cantata No. 170, pianist John O'Conor will play the Bach E Major keyboard concerto, and Manos will conduct the First Orchestral Suite of Bach, and works by Irish composers Victory and Armstrong.

Sunday night's American Festival program in the National Gallery will be played twice. The sole work of the evening is Joseph Ott's electronic score, "Locus 1977." The first performance of "Locus" will take place before the intermission, the second one immediately after intermission.