Yes, it is the weekend after Labor Day, and that means that your Classical Music Agenda has come back from its summer hiatus, tanned, rested, and ready. The classical music season is not yet fully under way — but some good music is waiting to be heard, including some of it for free, which is where we begin.

MAKE IT FREE:

Lawrence Brownlee, tenor

>> There is not all that much music written for the combination of piano, flute, and bassoon, but the Trelumina Trio will perform some on the Smithsonian American Art Museum’s Steinway Series at the Reynolds Center this afternoon (September 13, 3 p.m.). Pick up your free ticket to this concert in the museum’s G Street lobby, starting one hour before the performance.

OPERA:
>> Washington National Opera opened its new season last night with a production of Rossini’s Barber of Seville. Opera aficionados have probably already seen this perennial favorite far too many times, but it is always a good choice for a new listener’s first opera. The company is reviving David Gately’s fairly traditional production, which will offer few surprises — that could be either a positive or a negative, depending on your point of view. Some promising young singers are in the first cast, especially tenor Lawrence Brownlee — who excels in this kind of bel canto repertoire — and bass-baritone Eric Owens. The options include various times and two different casts in various combinations almost every day this week (September 13, 14, 15, 16, 17, 19, and 20) in the Kennedy Center Opera House.