In his Symphony No. 1, Mahler places trumpets offstage for a fanfare and asks winds and brass to play with their bells in the air. He has the line of eight horns stand while belting it out. In terms of unusual instrumental choreography, though, he's got nothing on Jennifer Higdon's On a Wire.

Both works were played by the Philadelphia Orchestra Thursday night in Verizon Hall, and while Mahler's special instructions are at least partly about visual drama, there can be no doubt that Higdon's directions were about achieving a multitude of specific musical effects.

On a Wire starts with its soloists playing playing piano. Six soloists, one piano. They stand around it, reaching into its body like so many doctors at an operating table. The innards of the piano get bowed, struck, and manipulated in various ways. As the piece proceeds, players return to their other instruments — strings, clarinets, flutes, cello, and marimba — and a kind of concerto grosso emerges. The soloists are Eighth Blackbird, the contemporary ensemble for whom the piece was written, and in this, their first time with the Philadelphia Orchestra, the performance was expert (they had also memorized their parts).

The music itself? It's very much in Higdon's usual pleasant voice, heavy on percussion, and using effects like the clarinetist who makes popping sounds by removing the mouthpiece and smacking the end of the instrument. It's a piece that floats and dreams, develops some tension, and floats and dreams some more. Higdon has been a good ambassador for new music, but I sure wish I heard more substance in her language — shapely phrases or innovative harmonic progressions.

If On a Wire evokes the mood of wind chimes, Mahler's Symphony No. 1 draws images of greater specificity. Stéphane Denève was on the podium, once again showing himself as a musician who thinks in terms of sweep before detail. In places, this performance was still finding its footing. But several individual performances stood out, especially in the third movement dirge/klezmer hybrid. Joseph Conyers handled the opening bass solo with a subtle shape and direction, and oboist Richard Woodhams was in his usual solid-gold form. When instrumental blending was good, it was very good, as in one spot that had three flutes piling on silken sound by the yard.

Denève grants players a great deal of freedom. This played out most comfortably in the schmaltzy quieter interior section of the last movement, and in many of the evocations of bird calls, flowing water, and a distant cavalry that suggests a mysterious Maxfield Parrish-like world beyond.

Additional performance: 8 p.m. Saturday at the Kimmel Center, Broad and Spruce Streets. Tickets: $51-$153. Information: 215-893-1900 or