This final Lahti Festival concert was given by the home band, the Lahti Symphony Orchestra under their principal conductor, the 70-year old Okko Kamu, whose tenure is about to end. The Sinfonia Lahti (as they call themselves here) has a nicely choreographed way of coming on to the platform in sectional groups, and standing until they are all assembled. They seem to suggest that in a sense a ‘performance’ begins before they play a note.

It is not a large band, with a string section founded on just five double basses. They are all municipal employees of Lahti’s local government and we understood that the bill gets raised as an issue in the Council Chambers quite often. The players know this splendid hall well, and are not so few that they cannot fill it with a glowing sound when required. The Sibelius Hall can be acoustically adjusted, being a wooden enclosure set inside a larger wooden structure. Panels around the hall can be opened to allow a greater acoustic space for reverberation and for bass resonance, as was the case on this occasion, when the huge panels behind the choir stalls were rotated through 90 degrees. Then they sounded just like the Helsinki and BBC orchestras from earlier in the week (each with eight double basses), when those panels remained closed.

Okko Kamu’s Sibelian credentials are second to none, even if the work of others such as Vänskä and Oramo (both of whom also appeared at the Festival) has had a higher profile in recent years. As artistic director of the Sibelius 2015 Festival, he seemed here to give himself one of the tougher assignments of the week, to close the orchestral concerts with four of those Sibelius work which emphatically do not play themselves. No music is less conductor-proof than that of Sibelius, as once in a while an over-ambitious time-beating Kappellmeister has discovered. But a programme of The Oceanides, Pohjola’s Daughter, and the Sixth and Seventh Symphonies offers a fair number of problems to solve: of balance, pacing, persuasive transitions, and getting all those passages where there are different kinds of motion in different parts just right.

It was clear from the two tone poems in the first half that there were few places in the world where all this has been worked through so often it comes as second nature (well, almost), and the musicians can just play. Kamu uses a score, even though he has been conducting these pieces all his life, and he looks at it too. There is a sense that we hear what is liberated directly from the page, not what tradition has added. The Oceanides had all the Homeric nobility one could wish for, and Pohjola’s Daughter, one of the greatest symphonic poems by anyone and the best known of these four works perhaps, was outstandingly successful, with a shattering climax.

The Sixth Symphonyso often seems an enigma, and that is undoubtedly part of its character, can be made to sound inevitable from start to finish, with the right tempi, thought-through tempo relationships, and exactly judged balances. All these were on offer here, and there was no more complete performance of any Sibelius symphony to be heard this week, which is saying something. The Seventh was in the same vein, and at least it followed after a pause when the conductor left the stage. In the Seventh, it was the tempo transitions that were so impressive. One was aware that a new tempo had been established, but not exactly how and when, surely the effect intended, just as one can never pinpoint the exact moment when the Nordic winter yields to Spring. Thus the four sections merged into one vast orchestral soundscape, punctuated by the noble trombone theme, whose first note, that alien D, intrudes so irresistibly upon the swirling C major tonality. Kamu made this moment and all that followed feel inexorable.

Strictly speaking the final concert of the Lahti Festival was the next morning’s song recital. But for the large international audience thronging the concert venue, this was the climactic occasion, and that was underlined both by the 5pm start to allow plenty of time for celebratory feasting afterwards. Many Festival-goers had made pilgrimages to Sibelius’ evocative home at Ainola and to the Helsinki galleries to see those Kalevala frescoes and paintings of Gallen-Kallela, so familiar from the Sibelius literature and CD booklets. But if there was anything missing, it came at the end of this concert and the inevitable encore of Finlandia. By then no other piece would really do, as all we foreign visitors had now discovered our inner Finn during an intensive week of magnificent music making. One hopes the city fathers were there to see the international acclaim the orchestra brings them.