This week, the free concerts are at the top of my classical music picks, because everyone loves to hear music for free, especially when it promises to be of such high quality as most of these concerts.

LIBRARY OF CONGRESS:
>> It is finally time to go hear excellent chamber music at the Library of Congress again. This Wednesday (October 11, 8 p.m.), one of the finest chamber groups around, the Beaux Arts Trio, will give a recital in Coolidge Auditorium. If you want a guaranteed place to sit, reserve through Ticketmaster (with the usual fees). If you can handle possibly not getting in, wait on line for an unused ticket. The program includes two pieces by Schubert (a notturno and the first piano trio), a recent work by London-based composer Mark-Anthony Turnage (A Slow Pavane), and the Shostakovich second piano trio. Although they played the latter work in their last concert at the LOC two years ago (when I heard them), they play it again this time to celebrate the Shostakovich centenary. (First St. and Independence Ave. SE)

>> I will likely be right back at the Library of Congress on Friday (October 13, 8 p.m.), for a free concert by the Mandelring String Quartet, a group from Germany that I have not yet heard live. Their program includes a Haydn quartet (op. 20, no. 3), a Brahms quartet (C minor, op. 51, no. 1), and for the first time at the Library, Ligeti’s second quartet. When Hungarian composer György Ligeti died this summer, most critics (myself included) lionized him as the greatest composer of the late 20th century. Although his more outrageous pieces, like the infamous Music for 100 Metronomes, may be more stunts than compositions, his second quartet is a profound experience of Ligeti’s melodic and harmonic invention.