In a world where our online arteries are clogged by instant messaging, it's easy to make connections across the miles. Twitter, Whatsapp, Skype and countless other methods of communication enable friendships to grow between people who've never met. Is it easier to unburden one's soul to a virtual stranger? 140 years ago, a remarkable correspondence began between the composer Pyotr Ilyich Tchaikovsky and Nadezhda Filaretovna von Meck, the woman who would become his great benefactor. Despite an exchange of over 1200 letters, in which von Meck provided moral, as well as financial, support, they chose never to meet, even though Nadezhda's son married Tchaikovsky's niece, Anna Davydova, in 1884. “Beloved Friend” is the term Tchaikovsky used to address Nadezhda in his letters, and it is the title Semyon Bychkov has given to his Tchaikovsky series, of which this concert with the BBCSO closed the Barbican leg.

There is so much biographical speculation about the Sixth Symphony – Pathétique – that's it's difficult to divorce the work itself from our knowledge that nine days after its first performance, Tchaikovsky was dead. The rumourmongering began. With its unusual form, ending with a long, slow movement which peters out into nothing, had Tchaikovsky foreseen his own death? Was the Pathétique a suicide note? Bychkov's interpretation of this final movement was highly unusual, ploughing through it in little more than nine minutes – the fastest interpretation I've experienced. Basing his tempi on Tchaikovsky's metronome indications on the original score (read this interview), Bychkov didn't allow the strings to wallow in a long drawn out death. Instead, there was always momentum, a regular pulse to the double basses' ostinato until it just stopped. Not an interpretation to move one to tears, but one that shocked in a provocative, thoughtful way.

The rest of the Sixth had been given an efficient performance by the BBCSO. Principal clarinet sounded a touch anaemic in significant solos, but Bychkov allowed plenty of fat on the strings to caress Tchaikovsky's yearning phrases and there were some poetic bassoon solos from Amy Harman. The 5/4 waltz was light and airy, Bychkov tracing great arcs with his baton, before a slightly hectic March bustled the orchestra a little faster than it wanted to go, the brass involved in a mad scramble towards the conclusion. After the inevitable applause, Bychkov rightly waited a long time to launch the Adagio lamentoso.

There was a great connection between Tchaikovsky and Rachmaninov. When he left the Moscow Conservatory, Rachmaninov wrote the one act opera, Aleko, for his composition graduation piece. Tchaikovsky was on the jury and awarded it the highest grade, but surrounded it with plus signs. When Tchaikovsky played through the Pathétique at the piano, at a gathering before it was premiered, Rachmaninov was present. He had planned to attend the première of the Pathétique, but had to catch a train to Kiev to conduct Aleko instead. On hearing of Tchaikovsky's death, Rachmaninov began composing his Trio élégiaque in tribute.

Before the Pathétique, Bychkov programmed Rachmaninov's choral symphony The Bells, composed to verses by Edgar Allan Poe. In Russia, bells chart significant steps through life's journey, but are often associated with melancholy; even the “Mellow Wedding Bells” are tinged with sadness. Despite two reliable soloists and one excellent one – Anatoli Sivko's slavic bite making far more of the text than either Vsevolod Grivnov or Emily Magee – it was the orchestral contributions which impressed most. Rachmaninov doesn't restrict the chimes to the percussion section. Yes, glockenspiel glitter contributed to the ear-tickling tintinnabulations of “Silver Sleigh Bells”, but bells also tolled via the horn section, viola pizzicatos in “Loud Alarum Bells”, on the piano, and in rippling harp, pealing softly in the warm afterglow of the postlude. The BBCSO was on vital form here, the highlight being Alison Teale's keening funeral lament in “Mournful Iron Bells”. The BBC Symphony Chorus contributed strongly, doing its best Kremlin crowd impression in the third movement, where Rachmaninov almost channels the coronation bells from Boris Godunov, backed by resplendent brass playing. For an unburdening of the soul, this performance hit the mark.