Little about the Pacifica Quartet is actually calming. The way it floated down the tranquil second movement of the Schubert Cello Quintet in a concert at Carnegie Music Hall on Monday night certainly qualifies. But for most of the Pittsburgh Chamber Music Society event, the ensemble excited and invigorated the listener with incredibly impassioned playing.

I'd suggest a name change to Appassionata Quartet, but a quick Google search reveals that already is taken. In any case, you get the point: The Pacifica Quartet -- violinists Simin Ganatra and Sibbi Bernhardsson, violist Masumi Per Rostad and cellist Brandon Vamos -- is one of the top quartets in the world. They proved it in a program of Mendelssohn's Quartet in E-flat major, Janacek's Quartet No. 2, "Intimate Letters" and, with Paul Katz, Schubert's Quintet in C major for two cellos.

Typically a concert with the great cellist of the renowned Cleveland Quartet (active from 1969-95) would be the headline, and the Quintet was excellent, but the fact is, the Pacifica alone was the main story.

I have never seen such communication in a quartet. It's a wonder that any of the other three even looked at their parts, so often were their eyes focused on lead violinist Ganatra. Excellent ensemble work ensued. Ganatra not only cued the entrances and otherwise formed the phrasing, she kept the mood high, playing with a smile nearly throughout. After countless hours of rehearsal and performance, her constant confession of love for music must surely be inspiring for the others.

Inspiring for the audience was Ganatra's warm tone. In the Mendelssohn, she proved to be a Romantic with some sumptuous phrasing that took the melodic themes for all they were worth. Not sappy, mind you, but full-bodied and almost sensuous bowing, and the others played accordingly. Leaping forward a century for the Janacek, they didn't leave behind that Romanticism -- a quality actually latent in the modernist composer. The quartet gave a smooth and vibrant reading of the highly personal work, tracing Janacek's unrequited love.

The Schubert Quintet -- one of those works you simply have to hear at some point -- was balanced perfectly. Katz blended well with the others, and all of the players sang out when called for. However, even in the quieter moments, they kept the piece moving.

As for the quartet's name, they say they took it from the "awe-inspiring Pacific Ocean." Awe-inspiring pretty much describes the quartet as well.