Tulsa World Sweet Emotion Pacifica Quartet's performance was passionate yet restrained March 21, 2006 By James D. Watts Jr. The Pacifica Quartet's performances have always been infused with a passion that isn't often found in many chamber music ensembles. The group's performance Sunday at the Tulsa Performing Arts Center, presented by Chamber Music Tulsa, still had that crackle of urgency and emotion audiences have come to expect. But it was a passion tempered by maturity, heightened by the gentlest of restraint. In one of the quartet's previous visits to Tulsa, we described their way of playing as having the sort of spirit and wildness one usually associates with rock music. The program that they presented in the Williams Theater was one that easily could have lent itself to expressive excess, with pieces by Mendelssohn, Beethoven and Shostakovich. But while this music as played by the Pacifica Quartet packed all the emotional wallop one could want, there was not so much as a hint of histrionics in the performance.   Consider the Mendelssohn Quartet in E-flat Major, Op. 12. This could be presented as a real "heart on the sleeve" kind of piece -- burbling sentimentality in the second movement Canzonetta, over-ripe melodrama in the finale. The Pacifica's performance, however, was much more delicately shaded. They brought out the darkness and unease underlying the Canzonetta, and held the rampaging finale just enough in check for it to be superbly effective. Shostakovich's Quartet No. 8, Op. 110, is one of the composer's most autobiographical, written in the wake of Shostakovich succumbing to the pressure of joining the Communist Party. One can almost imagine this quartet a sonic portrait of the composer's mind -- one that incorporates bits and pieces of past works with music of darkness and despair. This dichotomy was ably contained in the quartet's performance -- sweetness and terror alternating without either overwhelming the other.   The afternoon concluded with Beethoven's Quartet in B-flat Major, Op. 130, performed in its original form with the 20-minute "Grosse Fuge" as the final movement. In his final quartets, Beethoven more of less exploded this musical form, creating music that sounds centuries ahead of its time. That's certainly true of the "Grosse Fuge," or great fugue, which can sound -- as Leonard Garrison, in his pre-concert lecture state -- "like a bunch of noise." The Pacifica's version of this quartet, however was sublime, from the forceful and dynamic first movement, through the fast and furious second, the gentle dance of the fourth movement, and the knottiness of the fugue. And it was in the Beethoven that a distinctive quality of the Pacifica Quartet came to the fore. Unlike some string quartets, the players of the Pacifica do not strive to create a homogenous quartet sound, of four voices joining into one. Rather, violinists Simin Ganatra and Sibbi Bernhardsson, violist Masumi Per Rostad and cellist Brandon Vamos work to keep their instrumental voices separate. It's an approach that adds an additional layer of intimacy to this music, so that it truly sounds like a conversation among equals, and it allows one to savor, for example, the incredible smoothness of Vamos' cello, the sturdiness of Bernhardsson's playing in contrast with Ganatra's intense and emotive style, and the rough-hewn warmth of Rostad's viola.