If you want to know about Riccardo Chailly and the Leipzig Gewandhaus Orchestra’s live performances of Beethoven symphonies 1, 2, 5 and 7, or the newly commissioned pieces that accompanied them by Steffen Schleiermacher and Carlo Boccadoro, I’m not the man to tell you. Life took me to Berlin and I missed the opening two concerts of Chailly’s Beethoven symphony cycle at the Barbican.

So I caught up mid-cycle: symphonies 3, 4, 6, 8, 9 and new pieces by Colin Matthews, Bruno Mantovani and Friedrich Cerha still there for the listening. But, now in Berlin, your roving LvB correspondent was quick witted enough to check out the Philharmonie website. And Bingo! Nikolaus Harnoncourt was conducting Beethoven 5 with the Berlin Philharmonic. Reckoning the opportunity to see two great conductor/orchestra teams play Beethoven in as many weeks is a rare one, I grabbed at the chance, and what follows are some musings about the sound of live Beethoven.

Why specifically the ‘sound’ of Beethoven? Because Chailly and Harnoncourt have the presence, and the technique of course, to impose themselves onto Beethoven and make their vision stick. The ‘music’ becomes a given, then you can appreciate a spectrum of detail and internal timbral/structural relationships off limits to conductors fazed by Beethoven and the cultural muscle his music carries.

Chailly is a rock star personality. He conducts the audience as keenly as the musicians. Big smiles, self-assurance in spades. Did you hear what that niggling chromatic note does to the structure? A percussion-tastic timpani outburst coming…3, 2, now! A drum solo! Dig it my friends. If he had his way Chailly would happily stagedive, Iggy Pop style, expecting the audience to suspend him midair. And surely they would.

But Harnoncourt is no more likely to behave thus as he is to secure gainful employment as a rodeo rider. His intensity is of a different order. Brusquely marching on stage at the Philharmonie, Harnoncourt has a job to do: once Beethoven’s Fifth is despatched to the best of his ability he will, if he must, traipse backwards and forwards to acknowledge applause. He’ll play the game, but with the music over, he’d rather be back at home marking bowings into parts.

Harnoncourt is 82; Chailly is 58. This Harnoncourt concert is a one-off guest spot; Chailly’s Beethoven is ‘event’ concert going, one conductor and ‘his’ orchestra. I’m not comparing like with like. Caveats come inbuilt. But there are surface parallels too. Both men opt to arrange the strings with (looking up from the audience) basses on the left, then first violins, cellos, violas, seconds. Harnoncourt sits the piccolo in with the brass for sound reasons, acoustically and intellectually. And the instant he issues a downbeat, hands hovering like hawk wings, metaphorical electricity forks around the building.

Sitting in front of the Berlin Philharmonic, I realise it is indeed a mighty beast. I retain a vivid aural memory of the subliminal French horn push that Beethoven drops into the texture (bar 34 in the score) to shore up his strings; of the insistent, probing stateliness of the horns a few bars later as they enter a call-and-response with the strings. But a passage further upstream in the third movement leaves a more indelible mark. After pinning his movement on blowsy primary orchestral colours, Beethoven reduces his instrumental palette down to the minutiae of pianissimo pizzicato strings, with interjections from the woodwind, the bassoon occasionally accenting the third beat. Harnoncourt fools these instrumental colours into being one sound: a troupe of insect ballet dancers; slight, fragile gesticulations.

But then a jolt. The bridge passage that connects ‘attacha’ the third movement to the finale – sustained strings underpinning an emerging pulse on timpani – transformed the music like Stanley Kubrick’s movie camera making an ape bone into a space ship. The symphony stepped outside of itself as Harnoncourt’s ‘camera’ rostrumed out from the microscopic string and woodwind detail to catch the oncoming sustained horizon: tiny detail exploded onto an epic surround-sound canvas. Strings marked ppp; timpani pp; the fourth movement pulling the music back to earth with a fortissimo thump. That’s an extreme dynamic range, especially for 1808, and Harnoncourt made the differential between ppp and pp properly count. The sudden crescendo into the finale was brutal and visceral. The woman sitting next to me yelped.

In Chailly’s Pastoral Symphony sound similarly liberated itself from Beethoven’s material when the first piccolo entry rolled the roof off the orchestra during the Thunderstorm sequence. Chailly nudges the piccolo up an extra octave: an elemental squeal. The sheer looming chasm between the orchestral firmament below and this shrill, whistling ozone layer is the perfect sonic analogy for a storm: the eye of the storm given geographic perspective. This Pastoral evoked craggy, perilous terrain. A stroll in the countryside it wasn’t.

Discussion of Chailly’s cycle obsesses about his tempi – his claims to take Beethoven’s metronome markings at their word, no matter how reckless – which is absolutely fair enough because he instigated it as a talking point. But Chailly’s tempi are academic unless you think about how tempo and sound interrelate. At his tempo double bass strings nip the fingerboard aggressively adding percussive clatter to Beethoven’s pitch material during the storm sequence. Sound that can’t be fully controlled nor contained. The string octave semiquavers in the Eighth Symphony reverberate like a pinball machine; the abrupt change of tempo in the Fourth Symphony’s opening movement buckles the structure. The Eroica’s funeral march becomes an endless parade.

Chailly’s project-specific commissions were designed to be symbolic of a continued contemporary resonance and were, but not always as their composers intended. Colin Matthews’ Grand Barcarolle was dutiful but lifeless: risk factor of nil. Mantovani’s Upon one note indulged in macho gestures that sounded impressive on the surface but without the harmonic imperative to justify them: an exuberant rant. Cerha’s Paraphrase über den Anfang der 9 Symphonie von Beethoven rebuilt the opening moments of Beethoven 9, tracing new lines along familiar harmonies-once-removed: an engaged response.

Then the Choral Symphony itself proved to be on the far reaches of the avant-garde still, its primal starting point – open fifths, the fundamentals of harmony – initiating a journey from this physical blueprint of sound towards the last movement’s deeply humane ode. An ode to the idea that conductors with vision can still puncture cosy assumptions about our musical DNA, an ode to everything that is great about the sound of Beethoven in fact.