Belcea Quartet, on emergency call, delivers fine Beethoven at Independence Seaport Museum

Handily established among the best chamber music groups of its generation, the Belcea Quartet has immersed itself in Beethoven over the last year, and through that composer, it has found a voice that ensures its place in musical posterity. Though the Philadelphia Chamber Music Society often feels like an ongoing Beethoven string quartet festival, Belcea's program Friday of the composer's demanding late works stood among the best, in a lucky afterthought to the society's season.

The Prazak Quartet was originally scheduled to play Friday at the Independence Seaport Museum but had to cancel its tour due to illness. The British Belcea Quartet had a Nov. 3 Carnegie Hall date and agreed to step in, flying into JFK Airport from Europe on Friday afternoon and performing that night in Philadelphia, where a power failure at the Seaport Museum nearly forced a venue change.

But the lights came back on, and the Belcea proceeded to play String Quartets Op. 95, 132, and 135, plus an encore in a concert lasting well over the usual two hours. Usually, jet-lagged musicians deliver musical information rather than the aura that surrounds it. The Belcea Quartet, still in the thick of its Beethoven odyssey, had a few messy entrances in Op. 95, but thereafter, eclipsed the lofty standard I'd heard in its broadcasts over the summer.

At times, the music unfolded with meaning arising so organically out of the score - even in Op. 95, which generally baffles me - you almost thought Beethoven wasn't being interpreted at all. The quartet's airtight intonation delivered, with clarity, musical information you didn't know you were missing in those decrepit old Budapest Quartet recordings or in the youthfully reckless concerts of the Cleveland Quartet. More important, Belcea used vibrato with thoughtful discretion, adding to the sense that the quartet was simply staying out of Beethoven's way.

Less vibrato meant even the softest playing had wonderful shades of color. Shifts in the instrumentation were felt much more strongly than usual. Slow passages in Op. 132 often had no vibrato at all, revealing the range of meaning within the pianissimos: One felt like a religious vigil. Another was grief. In Op. 135, pianissimos often felt like exhalations of infinite variety.

Some of the tempos elongated the music to what might've been the breaking point for some quartets, but not with the spellbindingly intense concentration of these musicians. So, interpretation was there, but was free of any one agenda (whether historic performance or faithfulness to Beethoven's metronome markings). But the music was fully internalized rather than played from a respectful distance or manhandled into submission. This was a landmark in my listening history.