Watching an orchestra rehearse is an intriguing, behind-the-scenes glimpse into the camaraderie behind the coat-tailed clad veneer of a polished performance. At work, on duty, playing passionately - though not for public scrutiny. All ensembles worth hearing should transmit a tight musical rapport when in concert, but in rehearsals you witness the personal rapport too. The exchange of jokes, raised eyebrows, smiles, casual attire, casual demeanour. Until they start playing of course, when professionalism instantly kicks in and we get committed, fully-focussed performances. The musicians sway, dive, exude intensity just as they would in concert – they just stop every minute or so, leaping between two dimensions of being with the same relaxed manner in which the rest of us might alternate between, say, looking at our screen or leaning backwards for a stretch. This is even more pronounced in a recording session, the red light acting like a switch between the prosaic and the profound: on, off, on, off. The Berlin Staatskapelle are rehearsing for the opening night of a four concert series at the Royal Festival Hall pairing Beethoven’s Piano Concertos with Schoenberg orchestral works. Explaining the link, Daniel Barenboim says: “Only a handful of composers in the history of classical music have had the capacity to summarise and even culminate the development of an entire era of composition, while at the same time pointing the way toward a radically different new paradigm or style.” Thus Beethoven’s early style grew out of the idioms of Haydn and Mozart, and Schoenberg’s from those of Brahms and Wagner, before they took music in a new direction. It begins tonight with early works – Schoenberg’s Pelléas et Mélisande (rooted in Romanticism, though still pointing to the future), and Beethoven’s Piano Concerto No 1. The forces for Pelléas are vast, and the rehearsal was episodic. The Beethoven, in contrast, was more of a collegiate affair, a smaller assembly around the piano, a run-through with occasional stops to refine this or that. It was interesting to contrast Barenboim’s conducting technique in each work. In the Schoenberg he seemed to draw sounds out of the orchestra with sweeping gestures, in the Beethoven it was as if he were pushing the sounds up and out from within the body of players. Perhaps this was about the difference in style – lush Romanticism, buoyant classicism – or perhaps the subconscious result of being either perched on a stool above the players with a score, or among them making sounds of his own. For those lucky enough to have tickets for the series (it sold out six months ago), it looks destined to be a thrilling excursion. And for those without, something of the atmosphere can be still be imbibed for free in the Royal Festival Hall’s foyer, where the concerts are being relayed live on a big screen. More information at the South Bank Centre website.