It seems difficult for historically accurate concerts to avoid a certain evangelical tinge. Missionary fervor was definitely in the air last night when the Smithsonian Chamber Players and guest artist Jaap Schroder presented a program of 18th-century music on 18th-century instruments.

Once again there were program notes to remind us that 20th-century ears may be too jaded to accept the authentic sounds. In defense of contemporary ears, let it be said that though they are different, they are not necessarily jaded. Authenticity is merely a means to the end of making music that any ear in any age can respond to when properly done.

It is a composer's idea that endure, and clothing them in instruments of the period is but one of several valid means of communication. Whenever the listener's mind is more on the means than on the music, something is wrong.

Last night, when music-making took over, the concert was a fresh and joyful experience. Violinist Schroder propelled a particularly delightful performance of two Mozart concertos. But when the players came thumping down with righteous certainty upon the first beat of every measure in Bach's double violin concerto, no amounf of authentic sound could rescue the flow and beauty of the music.