For conductors and orchestras, playing a Beethoven symphony cycle has long had all the mystical underpinnings of a rite of passage, and audiences have always regarded such traversals as special events – as have orchestra managements, who see them as an almost foolproof way to fill houses.

You can see why. Hearing any composer’s complete output in a single genre – symphonies, sonatas, quartets – means following an artist’s aesthetic development, often (as in Beethoven’s case) with biographical elements clarifying the path, helping to explain some of the artistic changes taking place, and even offering clues, however debatable, about the works’ underlying meaning. In Beethoven’s case, there is an added element – the fact that his symphonies show him methodically shredding the rulebook of Classical style, and ushering in the wilder and more openly emotional universe of Romanticism.

Robert Moody and the Portland Symphony Orchestra have been working through the cycle for the last three seasons, and on Sunday afternoon at Merrill Auditorium, they – along with ChoralArt and the Oratorio Chorale, soprano Mary Boehlke-Wilson, mezzo-soprano Margaret Lias, tenor John McVeigh and baritone Philip Cutlip – put the final stroke on the series, with a vigorous, beautifully played, slightly quirky performance of the Symphony No. 9 in D minor (Op. 125). The performance will be repeated on Tuesday evening.

Few works are as fraught with extra-musical associations as the Ninth, which has been quoted plentifully in films, pop songs and television commercials – and perhaps most famously, for those of us of a certain age, as the theme of the “Huntley Brinkley Report,” NBC’s nightly news show from 1956 to 1970.

Of course, it had an extra-musical meaning for its first listeners, too: Beethoven’s finale is a grand setting, for choir and soloists, of Friedrich Schiller’s ode, “An die Freude” (“To Joy”), a poem that is essentially a secular prayer for universal peace and love. A choral finale was unusual for a symphony – the work basically morphs into an oratorio – although Beethoven experimented with mixed forms as early as the Choral Fantasy of 1808, a piano concert with a choral component.

For many listeners, that finale is the core of the work, and expectations are so high that it is easy to find interpretive points worth quibbling over in virtually any performance. For me, there were several here. The section preceding the baritone’s entry, with Beethoven’s introduction to the Schiller text – “O Freunde, nicht diese Töne!” (“Oh friends, not these sounds!”) – is dissonant and troubled, meant to be so cacophonous as to warrant the baritone’s interruption. Moody’s reading of this section was oddly bland.

Other passages were overthought. Moody warned listeners, during his pre-concert talk, that he took an unusually free view of the fermata (a “hold this note” symbol) at the end of the line “und der Cherub steht vor Gott” (“and the cherub stands before God”), and indeed, he held that “Gott” for an unusually long time.

It wasn’t clear what he had in mind, apart from the desire to dwell on a particularly dramatic moment. That is certainly Moody’s prerogative. But the move actually undercut the drama, instead of magnifying it: Listeners who might otherwise have been focusing on the climactic effect of that passage, and the starkly contrasting Turkish march that follows it, instead found themselves wondering what Moody was doing, holding that chord so long.

There were fleeting problems elsewhere – exaggerated tempo changes in the opening movement, for example, and passages in the Scherzo that demand suppleness but sounded breathlessly mechanistic. But for the most part, this was a solid, powerful Ninth, with some magnificently vehement singing from the large choir and superb playing from every department of the orchestra. Among the soloists, Boehlke-Wilson and Cutlip gave powerful accounts of their music; Lias and McVeigh sounded underpowered by comparison.

Moody prefaced the Ninth with Samuel Barber’s luminous “Adagio for Strings,” another work with a rich history of extra-musical associations, having been used at presidential funerals and other times of national mourning. Moody’s reading was slow and thoughtful, and showed off the considerable richness of the orchestra’s string tone. As in his recent Brahms “German Requiem” concert, he performed the opener and the main work without pause, and without applause, an effective, sensible approach for the music at hand.

Allan Kozinn is a former music critic and culture writer for The New York Times who lives in Portland. He can be contacted at:

allankozinn@gmail.com

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