Prom 60, Royal Albert Hall, London<br/>Prom 61, Royal Albert Hall, London<br/>Prom 59, Royal Albert Hall, London<br/>Prom 58, Royal Albert Hall, London

Some conductors leave you with a deep sense of calm. Others make you wonder if you drank too much Turkish coffee...

As is often the case with Mariss Jansons, the finest moment in the first of his two Proms performances with the Bavarian Radio Symphony Orchestra (Prom 60) occurred when the advertised programme had ended. What came before it was beautiful, fresh, assured: dynamic without a hint of bellicosity, inventive but never rash, meretricious or facetious, passionate yet ordered, even in the heroic statements, naive ecstasies, and anti-heroic rumblings of Strauss's Also Sprach Zarathustra. Sibelius's Valse Triste, on the other hand, was as refined, relaxed, and poignant a performance as you might hope to hear in a lifetime.

There may be more exciting conductors than Jansons, but I can't think of one with a finer sense of balance, a more eloquent baton technique, or a stronger respect for musical structure. First of two encores (the other was a tangy slice of Bartók's Miraculous Mandarin), Valse Triste acted as an epilogue to Jansons's tenderly wrought interpretation of Sibelius's Second Symphony, which captured both the lightness of the Beethovenian rhythms and the depth of sadness behind the long, regretful melodies. Calm, measured, but with an ever present sense of dance, the symphony saw an orchestra previously stretched by Strauss's tone-poem blossom in expressive confidence and mellow in blend. If Also Sprach Zarathustra had made one long to hear Jansons's other orchestra, the Royal Concertgebouw, play it, the Sibelius amply explained why Jansons has made Munich his other residency.

Having conducted Leila Josefowicz and the BBC Symphony Orchestra in his ravishing Violin Concerto (Prom 45), Oliver Knussen returned to the Proms with Claire Booth and Birmingham Contemporary Music Group to perform Requiem – Songs for Sue and Ophelia Dances (Prom 61).

Hearing Songs for Sue a second time, sung by the same soloist but accompanied by a different ensemble, confirmed my opinion that Knussen is without peer in this country as a writer for the voice, and is matched only by Henze and Adams in his sensitivity to poetry. There aren't enough superlatives in the dictionary to commend BCMG's performance of this tender, clever cycle of Ophelia Dances and, most especially, of Webern's Five Pieces for Orchestra, Opus 10. Never has this awkward, overblown venue seemed more intimate.

After nearly a month away from the Royal Albert Hall, I had quite forgotten the vicissitudes of its acoustics. Can it really be that elbowing one's way to the front of the Arena is the only way to be sure of hearing every note? Where a full hall plus a seat near Door H afforded reasonable warmth and clarity for Prom 60, and a near-empty hall plus a seat near Door M lent total purity of sound to Prom 61, a full hall plus a seat near Door M produced a Doppler effect that drove this listener to distraction in Valery Gergiev's chaotic performance with the London Symphony Orchestra (Prom 59).

Under Gergiev, the LSO's clarinets have already assumed a darker tone, the brass a less glossy, generalised timbre, the strings a pleasingly forthright attack. Alas, Gergiev's radical reading of Tchaikovsky's Romeo and Juliet – both the slowest and the fastest I've heard – saw each flurry of semiquavers from the strings bounced back from the Grand Tier a microsecond later, turning what was a potentially excitingly, unsentimental, unusually punctuated account of this taken-for-granted overture into a stuttering mess. In the Barbican, it might just have worked. Here, it did not.

Any thoughts of scrambling to the Arena disappeared as soon as Alexander Toradze began to play Prokofiev's Second Piano Concerto. This is a notoriously difficult work: bizarrely proportioned, petulant in its lurch from dynamic extreme to dynamic extreme, and orchestrated in such a way as to conjure the blurred agitation of having drunk too much Turkish coffee. Gergiev's pursuit of narrative coherence was lost to grunting and banging and thumping and jabbing, as Toradze pummelled the keyboard in a way that would not look out of place in an Ultimate Fighting tournament. The piano didn't stand a chance, and neither did Prokofiev. Exhausted by this spectacle and perplexed by Gergiev and Toradze's Beavis and Butthead-like inseparability, I listened to the remainder of the concert on the radio.

Which is also how I heard Prom 58. Now I'd far rather listen to Nina Simone's version of "You Know How I Feel" than Michael Ball's, but I don't think the Bromsgrove Balladeer deserved the opprobrium heaped upon him when his Proms debut was announced by Nicholas Kenyon. After months of sniping, a certain chippiness inevitably coloured An Evening with Michael Ball. From "Don't Rain on My Parade" to the Agony in the Garden scene from Jesus Christ Superstar to Queen's "The Show Must Go On", Ball played up to his new role as musical theatre's martyr: an innocent entertainer unfairly castigated for performing in a venue that is in any case better suited to amplified showtunes than it is to much of the repertoire in the Proms.

However apprehensive Ball felt, however slapdash the performance of the BBC Concert Orchestra, his fanbase was clearly at home in the Albert Hall. They might not turn up for Shostakovich or Striggio, but they're the same people who book seats for Raymond Gubbay's operas, who buy records by Ball's guest artist, Alfie Boe, and bring their picnics to the Proms in the Park. Fine. Exchanging one audience for another seems rather pointless, but I can't say that hearing a genre I dislike delivered by an expert in that field was a significantly worse experience than hearing a great symphony wrecked by a substandard orchestra. If, as is rumoured, this format is to be repeated, it would be nice to see something less hermetically sealed. Morrissey with the Hallé, perhaps, or Tony Bennett accompanied by Antonio Pappano. That said, I wonder whether An Evening with... might not be to Kenyon what Iraq is to Tony Blair: the big idea his core constituency will never forget, and an awkward inheritance for his successor.

Further reading Daniel Grimley's fascinating collection, 'The Cambridge Companion to Sibelius' (Cambridge University Press)