MAHLER'S IN EXPERT HANDS WITH MTT.

Byline: David Mermelstein Correspondent

The Walt Disney Concert Hall's vaunted acoustics make it an ideal venue in which to compare things, a place for considered judgments about a singer's voice, a string quartet's tone or an orchestra's technical prowess.

Such an opportunity came Wednesday night, when the San Francisco Symphony played there for the first time. The orchestra's music director, Michael Tilson Thomas, made the journey last season, conducting the Los Angeles Philharmonic after an absence of nearly 20 years.

On that occasion, Thomas led a refreshingly upbeat performance of Mahler's dark Symphony No. 6. This time, he offered Mahler's last completed symphony, the recessional No. 9.

The days when Mahler's symphonies were considered the property of certain orchestras are long gone, yet both the San Francisco Symphony and the Philharmonic have laid claim to these works. The San Franciscans are even midway through a critically lauded, self-produced cycle on CD.

So expectations came with the territory on Wednesday. Yet from the moment Thomas (or MTT, the quasi-corporate moniker he favors) strode purposefully to the podium, he exuded focus and control.

Mahler's symphonies can sound rambling and indulgent in less-than- expert hands, but though Thomas often adopted relaxed tempi - the performance ran a full 20 minutes beyond what the program suggested - the music never stopped making sense. Neither was it predictable, in a performance studded with unexpected climaxes.

Credit goes to the players, of course, but just as Esa-Pekka Salonen has placed his stamp on the Philharmonic, so has Thomas made his mark on the Symphony, which he has led for a decade. Know another conductor who can coax trombonists to sound like amber?

Perhaps because Thomas and his orchestra make their home in San Francisco's acoustically challenged Davies Symphony Hall, a mastery of dynamics characterized their playing, with Thomas coaxing both near whispers and veritable explosions from the orchestra. And his unconventional placement of instruments - first and second violins on opposite sides of the stage, basses and cellos upstage at left, harps next to the timpani - also added to the singular sonic picture, at once bold, clear and unified.