The existential thickets of Bruckner's grand, 80-minute Symphony No. 8 awaited Philadelphia Orchestra listeners on Thursday, the sense of occasion fueled by music director Yannick Nézet-Séguin's longtime specialty in the composer's often-apocalyptic symphonic monuments.

Yet the concert started with Bach's modest Violin Concerto No. 2. What was that about? Might a headlong dive into Bruckner be too traumatic?

Like Bruckner, Bach was a church musician, though one certain in his faith. In contrast, Bruckner's Eighth encompasses ultimate degrees of faith, doubt, exaltation, hopelessness, triumph, and failure, all cheek by jowl, and unfolding in an expansive sound envelope with the augmented brass section doubling between French horns and Wagnerian tubas.

So trauma was possible, especially the way Nézet-Séguin conducts Bruckner — though for reasons that aren't what they used to be. What has changed between his 2009 recording with the Orchestre Metropolitain of Montreal, various broadcasts including the Rotterdam Philharmonic, and now?

On one level, nothing. He still uses the Robert Haas edition. (Good choice.) The timings of each movement vary only by seconds over the years. The out-of-body experience that is the slow movement — where Nézet-Séguin is at his best — clocks in at 29 minutes every time. Yet within that framework, much has changed — often as a matter of circumstance.

In 2009, the Montreal orchestra played in a church acoustic, prompting a stately manner and homogeneous aura that left many of the long, repetitive transitional passages sounding long and repetitive. With Rotterdam, such passages more successfully took on escalating tension, though the quality of the playing wasn't as high.

With the Philadelphians, every choir within the orchestra had its own precise sonority, the strings with their trademark amplitude, but no extraneous prettiness. This precision created aural distance within the orchestra, the different sections coexisting more than meshing. That distance yielded more details. You simply heard more Bruckner.

With his train of thought more clarified, Bruckner's obsessive side was particularly evident, as if the composer was constantly saying, "Wait! There's more! And still more!" — with each minute shift in perspective.

Expressively speaking, Nézet-Séguin phrased with the kind of flexibility that made every passage bloom. Typical of him these days, he questioned received wisdom that made the third movement's fundamental rhythmic motif come out, well, different. More important, the orchestra offered depth of soul in the incidental solos. From oboist Richard Woodhams to French hornist Jennifer Montone, individual players are asked to convey miniature worlds in only a few notes, and sometimes only one. And they did. That's what makes the winding labyrinths and digressions of Bruckner's symphonic odysseys something to care about deeply.

The Bach concerto more than justified itself. The cut-down orchestra played as light as air, while concertmaster David Kim, the concerto's soloist, made expressive points with a slender tone and minimum vibrato. Never have I heard him play like that. Curiously, Nézet-Séguin had decrescendos at the end of many phrases. Usually, conductors do the opposite. In any case, my ears were suitably seized.

The Philadelphia Orchestra repeats the program Friday and Saturday at the Kimmel Center. Information: 215-893-1999 or