Empty seats - not a huge number but more than usual for this season - were to be expected at the Philadelphia Commissions concerts at Verizon Hall.

Though this city hosts substantial festivals of John Cage and Morton Feldman, more mainstream audiences didn't break down the Kimmel Center doors Thursday for the Philadelphia Orchestra's three new concertos featured in this week's concerts, even though Tan Dun's piece was a multimedia crowd-pleaser and music director Yannick Nézet-Séguin conducted Rachmaninoff's Symphonic Dances with such a compelling Russian accent that it, alone, was worth the concert.

Of the three concertos (all commissioned by the orchestra for its principal players), Behzad Ranjbaran's Flute Concerto was the fully realized winner (while the other two were maybes). Each movement starts with an upward glissando, like pulling back a curtain on an inner world that's explored in Persian-inflected solo flute soliloquies with a strong sense of subtext, reaching great emotional candor near the end of the slow movement in an eventful, satisfying musical journey. In less inward moments, the flute played a songful role that was engagingly hijacked by some mad flourishes taking the instrument to many extremes.

Still, the composer was realistic about the flute's solo limitations (even in the hands of the ever-excellent Jeffrey Khaner), and fashioned a rich orchestration that constantly shifts in color and gesture. Much of the orchestral writing was built around stark, punchy Shostakovich-style motifs, with blocks of interruptive rhythms - all used in tight structure with no wasted moments.

David Ludwig's Pictures From a Floating World, heard Friday, was more like a multimovement aria for bassoon and orchestra, with lush orchestral atmosphere and attractively unhinged lyricism suggesting Sheherazade on absinthe. Even with the emotionally vibrant soloist Daniel Matsukawa, much of this episodic piece felt like haiku with coy poeticism, trap-door meaning, indistinct conclusions - all possible virtues were the piece developed further and with more fantastical thematic invention. As is, some passages leave you hanging.

Tan's Nu Shu: The Secret Songs of Women, Symphony for Microfilms, Harp and Orchestra was the most elaborate, with field videos showing three generations of women in the Hunan province of China, passing on life wisdom in the form of song. Great idea, and since Tan is a master scene painter with music, the package has considerable legitimacy if only as an anthropological travelogue. It will be on the orchestra's 2014 tour of China.

But the 13 movements that touch base with key parts of the marriage cycle (plus placid nature scenes, rowing on the river, an architecturally elaborate covered bridge, etc.) lack a longterm tension-and-release structure that could make the piece more than a pleasant suite.

Some listeners hear covert Rite of Spring influences. In addition, I catch the expansiveness of Copland's Symphony No. 3. So there's musical variety here, including symphonic scherzolike movements amid the attractive folk melodies. But though harp soloist Elizabeth Hainen is called upon to create some magical effects (zitherlike flourishes, exotic arpeggios, and rhythmic hand-slap effects), she is also neglected, not playing in entire movements, and in other parts covered by the orchestration.

One senses that Tan the film director often overruled Tan the composer, in a piece that demands an equal balance. A similarly beguiling audiovisual package, Two Boys, now at the Metropolitan Opera, also raises the question: Does the hotness of the video allow or encourage the composer to underachieve?

Additional performance of the Ludwig and Ranjbaran concertos: 8 p.m. Saturday at the Kimmel Center. Information: 215-893-1999 or www.philorch.org.