The main source of color and movement was conductor Herbert Blomstedt. To a listener who was, well, listening, his contribution began formidably in the Mozart "Gran Partita" Serenade, and paid increasing dividends in Brahms' Symphony No. 1.
Mozart benefited from a feedback loop of great confidence with a superlative group of 13 instrumentalists. Blomstedt's fingers and hands are, in themselves, an elegant visual - something to highlight with video. No doubt, though, the main work happened in rehearsal. Had he given players the phrase "country dance" in preparing the rollicking fourth movement, or "military march" in the last?
However he communicated, the atmosphere of trust produced a cohesion that belied the number of rehearsals. Harold Robinson alternated between an enveloping foundation double-bass sound and something much more nimble. That the oboes were the penetrating top of the sound pyramid was to Mozart's credit; that they could blandish phrases with the expressive meaning of a singer was all the doing of oboists Richard Woodhams and Jonathan Blumenfeld. Horns both French and basset were a rich center.
At 86, Blomstedt is a dynamic presence, while emitting an inner beat that is simply clocklike in its assurance. This was no less true in the Mozart than in Brahms' Symphony No. 1. And yet, there was a passionate bend to the tempos in the Brahms. He clarified textures for that repeated first-movement figure recalling Beethoven's Symphony No. 5. He dug into the sound. Juliette Kang, concertmaster for the night, took her solos in the second movement with a big-boned sense of liberation that captured both sweetness and strength.
Blomstedt laced his judicious drama through the piece, but never more so than in those foreboding movements leading to the final dash. Whether through the authority of his interpretation or podium visuals, he had complete buy-in. The ensemble was like a single creature hearing its master's voice.
Additional performance: 8 p.m. Saturday at Verizon Hall, Broad and Spruce Sts.
Tickets: $10-$105. Information: 215-893-1999 or www.philorch.org.