Keeping track of Yannick Nézet-Séguin via recordings requires a global grasp of the classical recording industry.

Live recordings by the Philadelphia Orchestra music director — taken from his concerts with European orchestras — still pop up without warning. Only a few days ago, an all-Poulenc disc with the London Philharmonic Orchestra came out of the woodwork, with performances dating back five years. His Rotterdam Philharmonic Orchestra output alone is spread over three companies – Bis, EMI, and Deutsche Grammophon. Because recording in the United States is more expensive, Philadelphia Orchestra recordings have arrived fitfully — a Rite of Spring here, a Bernstein Mass there.

Increasingly, Nézet-Séguin's recording presence is consolidating around the prestigious Deutsche Grammophon. The six-CD Rotterdam Philharmonic Orchestra Collection, out at the end of August, celebrates his departure from the orchestra after 10 years with heavyweight repertoire. His DG-label Mozart operas with the Chamber Orchestra of Europe has yielded La Clemenza di Tito with a blue-ribbon cast. One of DG's high-profile fall releases will be the Philadelphia recordings of Rachmaninoff piano concertos with much-acclaimed Daniil Trifonov. More Rachmaninoff and Bernstein recordings are in the cards. All of Nézet-Séguin's concerts in Philadelphia are recorded with a special microphone setup and an ear for releasing selected live performances on DG in the future. So anything from the Sept. 13 "Candide" overture to Bernstein's Symphony No. 3 ("Kaddish") in January are likely candidates for release.

And what do these new recordings tell us about Nézet-Séguin's musical evolution? Everything.

No revolutionary, Nézet-Séguin emerges as a moderate revisionist. He'll question tradition: The rock-music influence in Bernstein's Mass that embarrasses older listeners is, to him, a multicultural feast. The London Philharmonic disc discovers intense anguish under the suave surface of Poulenc's Piano Concerto. Reversing that equation, Nézet-Séguin makes no apologies when the same composer slips into secular mode during the rather sacred Stabat Mater.

In a problem opera such as Mozart's La Clemenza di Tito, Nézet-Séguin is a conciliatory presence. Written quickly for a coronation in Prague, Tito shows Mozart turning away from real-people operas for which he is most beloved and dramatizes figures from ancient Rome with a formality more characteristic of earlier ages and often without the dramatic thrust of, say, Don Giovanni. Deadline pressure forced Mozart to delegate recitatives, probably to his student Franz Xavier Sussmayr. They serve an informational function but add to the sense that the opera is a bit generic. Important moments and key characters are as great as any Mozart. Secondary characters have music that could be written for anybody.

No wonder even conscientious conductors play fast and loose with the opera, often cutting recitatives, or in the case of conductor Teodor Currentzis, inserting parts of Mozart's earlier Mass in C minor. Nézet-Séguin seems never to doubt the piece. If Mozart repeats processional marches in the score, so does Nézet-Séguin. The lean sonorities and fast tempos of the authentic instruments are in evidence here but aren't extreme. This is a reference recording, good for knowing what the opera is and is not. Though not taken from a full stage production, the recording is so well-rehearsed it's one of the cleanest Titos out there. In Mozart's other operas, the intention behind the notes is paramount. In Tito, the intention is in the notes, and you hear all of them.

The cast's stars use vocal color to wring dramatic specificity from the opera. Joyce DiDonato was born to sing the trouser role of Sesto, who is manipulated by love into burning down the Roman capital and is tormented every step of the way — characterized with some of the most chilling notes ever to come from her lower register, all infused with quavering humanity. Marina Rebeka conveys the blind ambition of Vitalia without turning gothic.

The set's most distinctive but problematic asset is Rolando Villazon in the title role. So often, Emperor Tito seems to take the moral high ground because he hasn't the guts to do otherwise. No danger of that with Villazon's commanding treatment of the recitatives. But having made his name on big-voiced Italian repertoire, Villazon is wired for projection rather than precision, which means indistinct passage work and vocal trills that are part of Mozart's language. The visceral value of Villazon's charisma is immense. But he is bound to be a polarizing presence here.

In the six-disc Rotterdam box, Nézet-Séguin's operatic sensibility is never far away. The more classically proportioned Beethoven Symphony No. 8 , Dvorak Symphony No. 8, and Haydn Symphony No. 44  show the orchestra to be in excellent working order, but also tell a story — whether anything resembling a plot is at hand. Even in the loftiest moments of Bruckner's Symphony No. 8, the wind soloists have a soliloquy-like characterization. All inner voices and other subsidiary elements in any given symphony are underscored to create strong continuity and good foundation. Thus, when the symphonic content is projecting a string narrative, the piece's shape isn't distorted. Tchaikovsky's Francesca di Rimini, Mark-Anthony Turnage's Piano Concerto with Marc-Andre Hamelin, and Debussy's Nocturnes are like operas without words — though extremely different ones. The one puzzlement is the slowish Concerto for Orchestra by Bartok.

The major triumph is the usually bewildering Shostakovich Symphony No. 4 with its musical non sequiturs battling ruthlessly while fugues are seemingly powered by air hammers. Shostakovich could've been sent to Siberia had the 1936 premiere not been cancelled. Conductors have struggled to make the piece hang together strictly as a musical entity, including Eugene Ormandy's pioneering but noncommittal 1960s recording with the Philadelphia Orchestra. Nézet-Séguin and the Rotterdam orchestra treat the symphony like a suite from the composer's bizarre, mordantly funny operas, The Nose and Lady Macbeth of Mtsensk — neither of which were widely heard until recent decades. Nézet-Séguin creates his customary foundation and hits upon the missing piece of this symphony's puzzle: Earthy, manic, silent-movie humor.

Elsewhere in these Nezet-Seguin performances, one listens in vain for surface personality traits — say, Arturo Toscanini's speed or Otto Klemperer's monumentality — as he makes good on his stated commitment to harness an orchestra's local culture, whether consciously or intuitively. How does that play out?

Mahler's Symphony No. 10 was recorded by all three of Nézet-Séguin's orchestras — on the new Rotterdam box, in an Atma label recording with his Orchestre Metropolitain Montreal, and on a Philadelphia Orchestra WRTI broadcast that's floating around the web. With it's expansive, elegiac melodies, and traumatic dissonances, the piece was written as the composer's health and marriage were failing and can be heard as a personal confession as well as a symphony. The Philadelphia performance, the last to be recorded, has the best of all worlds. Montreal is the earliest of the three, and is the most emotionally fearless, veering to the confessional side, but with a bit of strain. The less-sprawling, highly satisfying Rotterdam performance is the most purely symphonic. Each has special differences: Montreal, for example, gives an extra halo to Michel Bettez's beautiful bassoon solos with an emotional ripple effect on everything nearby.

The funeral drums of Mahler's final movement are the better litmus test. In Montreal, they're aggressive. Death is coming to get you. In Rotterdam, a city that rose slowly from World War II devastation, death is part of the landscape, passively claiming whoever is in its path. In Philadelphia, though, the drums are like gunshots. Unmistakably. This performance was given in May 2016 as the local homicide rate was rising, and the Paris terrorist attacks had happened only months before. And they say classical music is in an ivory tower?