At 85, Gunther Schuller is showing very few signs of slowing down — in any of the myriad musical roles he plays on the local scene.
Many composers these days do not conduct their own music, let alone standard repertoire, but on Tuesday night Schuller led the premiere of his ambitious new tuba concerto and also conducted the Boston University Symphony Orchestra in Brahms’s Fourth Symphony and the opening prelude from Haydn’s “Creation.’’
Two hours before the concert, when you might expect Schuller to be preserving his energy or taking one last glimpse at a score, the composer made a surprise cameo appearance at New England Conservatory’s Williams Hall, where he shared the stage with the Borromeo Quartet and led a probing exploration of his hyper-complex Second String Quartet, of 1965. Focused talk of tone rows was interspersed with philosophical musings on the deeper meaning of dissonance in music, and why composers are entitled to create “ugly’’ as well as beautiful art.