It was an evening of go big or go home. Koerner Hall is a world-class “acousticorium”. It has been praised for razor-sharp rendering of the sounds of soloists like guitarist John Williams, divas like Anne Sofie von Otter and Dee Dee Bridgewater, quartets like the Kronos and Takács, chamber orchestras such as the 28 strings of Gergiev’s Stradivarius Ensemble. Last night, this discreet hall was called upon to handle two titanic affairs: the Music for the Royal Fireworks by Handel, and Mahler’s Symphony no. 1 in D major.

Handel’s 1749 score for outdoors to please the English King (George II) called for 100 players, including twenty-four oboes, nine horns, nine trumpets, three sets of timpani, twelve bassoons, a contrabassoon, and a serpent, with parts marked for strings where needed (this night we did with fewer). Mahler’s idea of going big is revealed in a remark he made to Sibelius: “A symphony should be like the world, it must contain everything.” Mahler’s First Symphony, nicknamed “Titan”, though far from being his biggest, is scored for 100 players.

Nearly that number of chairs were arranged on Koerner Hall’s stage for the youthful members of the Royal Conservatory Orchestra. Johannes Debus, the much-in-demand conductor of the Canadian Opera Company, distributed his sections across the sound-stage to maximize the orchestra’s stereophonic effect. This strategy suited Mahler’s work, constructed from massive blocks of orchestral sound that melt into chamber music, morph into marching bands, stomp and whirl in country dances that descend into the funereal and rise like angelic choirs. Normally, it requires a very finely tuned and experienced orchestra to keep the edges of these contrasting acoustic plates from grinding as they pass. In this case, and in this space, the burgeoning bite of the youthful brass and the overly robust sounds that occasionally burst from other sections gave surprising insight into the modernity of Mahler’s succession of tableaux.

The opening chord had a Kafkaesque weirdness, an impression dispelled by the “cuckoo” motif, the subsequent mellow horn melody and main theme drawn from Mahler’s inexpressibly lovely Songs of a Wayfarer. They carried us back from modern “weird” into a lovely, 19th-century pastoral music-scape. Here the orchestra also lost its stiffness and achieved a fine transparency. Throughout the movement there are passages of tension, periods of agonizingly drawn-out waiting, that melt or burst in brass, banging, and shrill winds. The second movement is an extroverted celebration that waltzes through the “peasant” Scherzo, and the trio animated by Maestro Debus’ frankly passionate direction. There follows the ironic funeral march based on Mahler’s minor-key version of the round “Bruder Martin” (a.k.a. “Frère Jacques”). Yiddish Klezmer sections in brass, romantic string melodies based on the fourth Wayfarer song, alternate with the funereal round. These elements are so enhanced by the stereo sound-stage, which, despite an occasional roughness in performance, made Mahler’s part-writing come alive. The Finale is an apocalyptic battle of dark passions and tender yearnings. The tension between lyrical flows and disjunct, broken storms is mediated by passages of comic burlesque that prophecy the music of Kurt Weill. I owe this insight to Maestro Debus, who elegantly shaped Mahler’s descent into the maelstrom and his triumphant return.

Handel’s Fireworks celebrates a treaty that forced the French to recognize the German George II as King of England. The fireworks display disastrously set fire to the structure built to launch it. The “celebration” lasted nine hours, until two or three in the morning. Horace Walpole reports that “Scarce anyone had patience to wait for the finishing”. Johannes Debus led the much-reduced forces of his orchestra in a performance that was suitably jubilant and oddly relaxing. Once past the ceremonially paced opening of the pompous overture, a quicker section follows that blends the sonorities of brass, strings, winds and percussion in a pleasant weave. Debus seemed to animate his players with dynamic gestures and footwork. He seemed to lead them away from the ceremonial voice of the music into its more human, lyrical, carolling qualities. The audience, particularly the parents of the players and supporters of the Royal Conservatory, seemed pleased.