The Pittsburgh Symphony Orchestra strives to move audiences, but Manfred Honeck wants to see what happens when he physically moves the musicians first.

For concerts this weekend (8 p.m. Friday and 2:30 p.m. Sunday), Honeck will experiment with what he calls "old German seating," the onstage arrangement of the orchestra common in the 18th and early 20th centuries for composers from Haydn to Mahler.

In this configuration, the first and second violins face each other across the stage, with the cellos and basses adjacent to the firsts and the viola section next to the seconds. Essentially, the second violinists will sit where the violas now sit, near the edge of the stage, and the cellos will move to their old space. The winds, brass and percussion will not change position.

"We are in the middle of a process," says Honeck. "I am investigating what was common when composers wrote -- what they heard when they wrote the piece." That includes Mozart when he wrote Piano Concerto No. 21 (which pianist Lars Vogt performs with the PSO this weekend) and the Strauss family, whose waltzes and polkas are also on the program.

Old German seating is uncommon in the United States -- most major orchestras vary only by the placement of the cellos and violas, keeping the first and second violins together.

"There are probably lots of reasons why it changed," says Honeck. "The recording industry started around 1920, and the microphone quality was quite poor and they only used one in the middle, and the technicians asked for higher instruments on one side and lower on the other."

Honeck feels the old German seating could lead to enhanced listening between sections and a "better feel" for each other. But he also thinks the audience will benefit. "By separating first and seconds, you could hear imitation more clearly, like stereo." The move also accounts for the acoustics of Heinz Hall.

This season, the PSO will use the German seating only when Honeck conducts, and only when he directs older works. "When we play pieces from the later 20th century, we should play with the normal seating," he says.

Honeck plans on further addressing the way the PSO interacts with the Heinz Hall auditorium by adjusting the shell above the stage and likely building new risers. Former PSO music director Mariss Jansons dispensed with the latter in spring 2001.

"I would like to have the orchestra closer together," says Honeck, who is using the Artec acoustician firm. "[At] the moment we have the brass in the very back. I would like to be more tied together."

He also feels that higher risers (the winds currently are on short risers) will aid the strings, even if the louder brass are brought closer.

"When you are sitting equal, the trumpets are right behind you and it is a problem, but if they sit on risers, they play above you and not in your ear," he said.

Most European halls have steps that act as risers. But Honeck stressed that his adjustments are a work in progress and that if, "something isn't working, we won't do it. I don't want to repeat mistakes."