Tchaikovsky lands on a chord as a dancer does — which is to say, a lot of different ways, with each landing producing its own particular emotional effect. When the composer gets to an arrival point, he can make you feel triumph. Sometimes he moves toward resolution and slips instead to a deceptive cadence, and spirits crumble.

The chord arrival that cuts deepest is the one that multiplies the impact of what you see, which is where Angel Corella came in Thursday night in his own setting of Swan Lake on Pennsylvania Ballet. The company's artistic director is sensitive to music, and even if you didn't agree with every instance of pairing a phrase or chord progression with a corresponding movement in dance, you had to admire the inventiveness in some of the tension between the two.

The company has spent the year doing the three big Tchaikovsky pieces. The complete music to The Nutcracker is widely known, but Swan Lake (as with The Sleeping Beauty) is filled with music that never makes it into the concert suites or excerpts. The version stitched together by Corella retains some of the most familiar tunes with more obscure corners of the score, and it challenges the orchestra.

Dance has its own set of needs, of course, so conductor Beatrice Jona Affron and the Pennsylvania Ballet orchestra can't be held responsible for tempos, pacing, and other matters. You had to feel for violinist Luigi Mazzocchi, whose vast solo, played well, was slowed beyond the musically reasonable, presumably for dance-related reasons.

But the ensemble does have some work to do. Opening night sounded tenuous in spots. The most obvious deficit was a depressed level of individual instrumental charisma. Energy on stage was often lacking a mirror image in sound from the Academy of Music orchestra pit.

Near the opening, you wished for a trumpet soloist with moves as stylish as the men on stage. Yes, the job is to support the dance. But shaping a phrase wouldn't mean violating the music's inner beat. The cello section wasn't able to always find a uniform sonority.

These qualities stood in stark relief to some wonderful playing. Affron is a strong leader, and she often drew a feathery texture from the violins. In the "Dance of the Little Swans," the plucky gestures of four ballerinas were heightened by a corps of tight, reedy woodwinds. Harpist Mindy Cutcher had some genuinely individualistic moves in a cadenza.

I didn't hear this season's Pennsylvania Ballet Nutcracker, but a lot of the orchestra's qualities Thursday echoed what I heard at The Sleeping Beauty in the fall. The ensemble needs to be a bit bigger (more strings). A greater sound presence would have a huge payoff, and not just in the music.

Dance music is akin to movie scores. The ears put real emotion behind what the eyes take in, even unconsciously. Corella has talked a lot about making sure sure uniformity and charisma materialize on stage in all the right places. The dance deserves no less, and neither does the music.