The Miami String Quartet's concert at Strathmore Hall Arts Center Thursday night combined imposing virtuosity with unforced, reflective commentary on how complex music is put together. Minute imperfections of execution that plague lesser ensembles were absent, and the clarified diction of the performances was expressively convincing.

The Ginastera Quartet No.1, Op. 20, draws on Bartok's harmonic language but is never derivative, beginning with an Allegro Violento that shocked and disturbed (violent film music sounds lame by comparison) and proceeding through sliding, whirring, whizzing figures punctuated by all manner of pizzicati, to a slow movement that suddenly erupted with deep viola-like sounds from the first violin, heard against a sinister, sawing drone. Odd animal noises--insects?--led to slashing sheets of sound, and when the piece ended one felt the exhilaration and relief of a kid on his first roller coaster ride. The Miami Quartet made it all work with a machined precision that slighted no hue of Ginastera's brilliant colors.

In Beethoven's late Quartet in A Minor, Op. 132, the composer's huge energies poured into cutting, impolite textures, the shuddering sighs, the brusque penetrating directness of utterance, and the imploded, personalized expressions that remain bewilderingly new. All came together in a performance that called no attention to itself but left Beethoven standing whole. The Mozart Quartet in D, K. 575, emerged gracefully and affectionately, without artifice or gloss.