It’s not often that you see a programme of music written entirely by one composer, but then again, as the programme cover said, “not all orchestras are the same”. The composer in question at this Queen Elizabeth Hall concert was Carl Philipp Emanuel Bach (1714–1788), the band was the Orchestra of the Age of Enlightenment with conductor Rebecca Miller, and the programme comprised five of CPE’s Symphonies, plus his Concerto in E flat for harpsichord and fortepiano. The concert was part of the OAE’s “Gamechangers” season, which aims to highlight a number of works that challenged the conventions of their time.

CPE’s music – at least on the basis of this concert programme – was more radical than his near-contemporaries Mozart and Haydn. Whilst elements of his compositional style alluded to the conventions of the day, he was a rulebreaker in terms of musical structure, harmonic shifts, and the emotional content of his music (notwithstanding the Empfindsamer or “sensitive” style, of which he was already a master), such that his “signature style”, if indeed he had such, was indiscernible; each symphony is unpredictable in its own way. Unlike those of Mozart and Haydn, Carl Philipp Emanuel Bach’s 20 known symphonies are relatively short works, with most around ten minutes’ duration, and consistently following a three-movement, fast-slow-fast pattern. But that is where the consistency stops.

The concert opened in dramatic fashion with the Symphony in E flat, Wq. 179. With its fizzing Prestissimo opening movement, it pulled the audience down a Doctor Who-style vortex into a very unexpected world of sudden turns of harmony and gesture. Even in the Larghetto, a pensive middle movement, there were some startling dynamic contrasts. The third movement, a Presto, initially conjured up images of a fast-paced hunt, but it was a theme that almost seemed to get carried away with its innate energy.

If anything, the Symphony in B minor, Wq. 182/5, was even more of a gamechanger. Beginning plaintively and quietly, a louder theme with a decidedly scalic pattern interjects completely by surprise. We heard multiple stopping in the violins – not unheard of by that time, but not exactly mainstream – as well as the melody’s constant ricocheting back and forth between the first and second violins, and harmonic progressions and key changes that would make even Gesualdo blush. Barely had one theme begun than another had already pushed it out of the way.

Crowning the first half was CPE’s quite remarkable Concerto in E flat for harpsichord and fortepiano, Wq. 47. Perhaps a touch more measured in its changeability than the symphonies, this concerto more than made up for this in the sheer peculiarity of having the old harpsichord and its new-fangled replacement, the fortepiano, playing almost equal roles: rather than being a compare-and-contrast exercise of idiomatic writing for each instrument, CPE creates dialogue between the two instruments, and between the soloists and orchestra. Melodies subtly shifted from soloist to soloist, and the moments of imitation brought out a well-natured, brotherly rivalry between harpsichordist Mahan Esfahani and fortepianist Danny Driver. The orchestra certainly seemed to enjoy its part, too. For all the energy that the soloists and orchestra put in, they proved themselves entirely adaptable to the frequent changes of mood, with a particularly gorgeous Larghetto and some surprisingly emotional playing from Esfahani on an instrument that once was dismissed as expressionless.

The Symphony in A, Wq. 182/4’s radical approach to texture hit from the very start: a rapid, high-pitched theme in the violins soon gave way to an entirely homophonic, decisively played few bars of a theme that cropped up again and again in the first movement. Similar contrasts were evident in the Largo ed innocentemente middle movement, though with an altogether more brooding sound. The melody in the Allegro assai, nimbly played by the various string sections, was on occasion accompanied with an usually forceful, ice-shard-like inverted pedal; by now, one had the feeling that CPE had taken all the conventional musical devices and rethought them to his rather different tastes.

The closing Symphony in D, Wq. 183/1 seemed to be almost future-facing, with sonorities and rhythmic patterns that were well ahead of their time, and a strangely convoluted passage from the Allegro di molto into the Largo that began in D and ended, curiously, in E flat. The final movement echoed the jubilatory opening movement before coming to a humorously abrupt end.

Initially, I had wondered just how much the differences in CPE Bach’s compositional style would be obvious in a programme that comprised items of the same genre. The Orchestra of the Age of Enlightenment, under the utterly brilliant, enthusiastic direction of Rebecca Miller, highlighted them at every turn with some wonderfully astute and animated playing; it proved itself eminently suited to playing these gamechanging works. As any good concert should, it has given me fuel to go and explore the often overlooked CPE Bach’s output in greater detail – surely a sign of a successful concert.