Programming works by Pierre Boulez alongside a high-profile Beethoven symphony cycle is an easy way to give exposure to the strikingly modern works of the Frenchman, but on seeing a substantial chunk of the audience disappear for an early drink before tonight's Boulez, I wondered if the Beethoven was perhaps too reliable a foil, leaving people little incentive to stay. This was a great pity, as Dialogue de l'ombre double created an amazing atmosphere in the hall and was an excellent inclusion in the programme.

Beethoven's Symphony no. 4 was composed three years after the groundbreaking third symphony and shows Beethoven returning to more formal classical structure and scale. Like the eighth, it is sandwiched between two far more popular works, perhaps accounting for its relative obscurity, but is nonetheless a wonderful mix of vigour and charm. Barenboim emphasised the latter, largely eschewing dramatic tempi all evening (until the final minute of the concert) in favour of clear woodwind articulation and clear, chamber-style interactions between sections. The West-Eastern Divan Orchestra perhaps lacked the richness of string sound which Barenboim gets from other orchestras, but they played with a focused and well-controlled diligence which worked wonderfully with the flitting musical lines of tonight's symphonies. Motifs were passed seamlessly between sections, most noticeably in the strings' descending quaver figure near the end of the Adagio. Barenboim maintained an easy, risk-free tempo, creating a fairly pastoral feeling in the second movement and the trio of the third. The fourth, by contrast, showed more incisive woodwind playing (the four principals were excellent), to which Barenboim gave full exposure by removing accompanying figures to a modest dynamic, and the articulate, propulsive dance of the wind was sufficient to set a man coughing in rhythm for several bars.

Conductor and orchestra left the stage, leaving only the young clarinettist Jussef Eisa for Boulez's Dialogue for solo clarinet and electronics. Eisa's virtuosity quickly became apparent, along with a sense of personality in his interactions with the recorded clarinet sounds coming from six loudspeakers high in the Royal Albert Hall. Impressions of bickering, fuller conversation and overwhelmed exhaustion were all suggested by his powerful performance. The round shape of the hall was a great asset to the electronics and left many prommers spinning on the spot, looking for the source of the sound; at one point the recorded sound flew dizzyingly around the circumference of the auditorium. The audiovisual aspects of the performance were brilliantly managed by Gilbert Nouno and Jeremie Henrot from IRCAM, balancing sound on- and off-stage perfectly, and supported by imaginative lighting. Another fascinating effect came from an off-stage piano, to which the soloist's music is relayed. With sustain pedal held down, the richly exotic resonance created is captured and directed into the hall. The twenty-minute performance was a fascinating and thoroughly enjoyable experience, and the link to the conversational chamber music of the fourth symphony was an interesting connection. Eisa and the sound engineers deserved greater credit for their performance.

The orchestra returned after the interval reinforced in the strings and with doubled woodwind for the imperial grandeur of the Eroica. This came at the expense of a small degree of clarity in large tuttis, and within the strings coordination was occasionally awry. The overall musicality was superb, though; the musicians gave the impression of being very well rehearsed in Barenboim's interpretation and of being well accustomed to playing with each other. Particular dynamic changes and phrasings of Barenboim's reading were without exception smooth and united throughout the orchestra, and as before the willingness of the players to listen and respond to each other was evident in interactions between winds and strings.

At the first movement's recapitulation the solo horn was restrained to a humble piano above string pianissimo, but their phrasing was absolutely aligned. The fine control of soft dynamics in the strings was used to especially good effect just before the climax of the second movement. In taking the strings to such a hush, the warmth from the ensuing major key of the oboe solo was all the more emotive and the bold fortissimo was given a clear context. The horns played beautifully in the later parts of the symphony, giving good character to the third movement trio through further close attention to ensemble playing. As with the fourth symphony, Barenboim created a relatively restrained and refined performance for the most part. The fourth movement's coda, however, was taken at a blistering pace. Whilst in its own right it was well played, it seemed incongruous with the rest of the symphony, in which elegance and clarity had taken priority over visceral excitement. Little was to be taken from the concert, though, and the indefatigable Barenboim is clearly shaping a superb Beethoven cycle.