"I like concerts to be slightly didactic -- in a nice, painless sense," says conductor Christopher Hogwood. Does he, then, always turn to his audiences and offer eloquent commentary on the program? When he brings his Academy of Ancient Music and its early instruments to the Kennedy Center on Saturday at 8:30, will he turn "didactic" and talk?

"It is sometimes nice and sometimes important to bring the audience into the picture, but it's not a mannerism," says Hogwood. "Sometimes it is perfectly apparent what I am doing, and I think there is some music that doesn't need a speech before it. I wouldn't talk before Mozart's 'Requiem.' But you can often talk before an unexpected version of some familiar piece; or before a work people know nothing about; or at a chamber concert, where it is on rather more intimate terms; or when you feel the atmosphere is stiff and old-fashioned and you'd like to loosen it up."

As for Saturday's concert, perhaps Hogwood will feel like talking about the basset clarinet (the only one of its kind in existence);that will be used for Mozart's Concerto in A for Clarinet. Or perhaps he will let Mozart and Haydn do all the talking.