Stravinsky called Beethoven's Grosse Fuge ''that absolutely contemporary work that will be contemporary for ever''. Looking over what has happened in Beethoven performance in the concert-hall and on record over the last two or three years I've had the growing feeling that the same is true of the symphonies. Just when everybody seemed to be saying that the mighty nine had been worked to death, along came Christopher Hogwood, Frans Bruggen and that provocateur par excellence Roger Norrington to shake us out of our complacency. Then, last month, came confirmation in Gunter Wand's Eroica that the traditional-classical approach can still be roundly satisfying.

And now this – a new Beethoven cycle which manages to combine the shock of the new with an uncanny sense of familiarity. Harnoncourt doesn't pretend that what he offers is Beethoven as the composer imagined it. With the exception of the trumpets, the instruments are all modern, and while phrasing, rhythmic articulation, expression and balance reveal Harnoncourt's rigorous and passionate pursuit of historical truth, the results neither sound nor feel like anything offered under that banner before. Right from the start – the slow introduction to the First Symphony – the feeling that emerges through the finely differentiated phrasing is surprising in its intensity.

So why 'familiarity'? Because listening to this set I was reminded over and over again how exciting it was to discover Beethoven's symphonies for the first time—I'm not exaggerating. One could argue for pages about Harnoncourt's theories on musical rhetoric in Beethoven's time, on musical genres as ''dramas or novels'' or ''the links between body movement and music''; what is beyond dispute is the vision that motivates Harnoncourt's music-making. The driving force behind many of the allegros is comparable with Toscanini, but unlike the familar NBC Toscanini cycle, or for that matter Roger Norrington, he can be flexible: rubatos, even allargandos, aren't uncommon, and important changes of key or character can bring minute tempo changes of their own—the kind of subtle inflexion Czerny observed in Beethoven's playing.

The most striking contrast with period instrument recordings, however, is in the slow movements. Harnoncourt's tempos can be pretty mobile, his phrasing sharply featured, but the emotional generosity, the telling contrasts of mood and colour suggest older models. Even Gunter Wand (RCA), excellent as he is, doesn't equal the expressive range and penetration of Harnoncourt's Eroica Funeral March, and only Carlos Kleiber (DG) amongst recent-ish versions matches the superb drama of light and scale in the Andante con moto of No. 5. And what happens on the large scale is often mirrored in miniature. In the Adagio of No. 4 the dotted figure in the first bar keeps its tension not only through the long diminuendo but even while the violin line sings warmly above—two very different voices, each to play a major part in the drama that follows. I admit there are places where I missed the sharp definition that period instruments can bring to Beethoven's textures, but given the resources he is working with Harnoncourt's achievements can be near-miraculous. Here, and in many other passages, I was repeatedly impressed by the way the COE not only take on board Harnoncourt's ideas but give expression to them so naturally. There's nothing studied: the Pastoral breathes freely—even in the ''Szene am Bach'' the sharply 'classical' pointing sounds entirely natural—while each movement of the Seventh dances, athletically, gracefully, titanically, but always with a combined sense of freedom and tight control.

A warning voice suggests that I ought to tone down the encomium a little. All right, I do have a few quibbles: I can do without both scherzo repeats after the trio as in Nos. 1 and 2, and his continuing the finale of No. 5 at virtually the same pulse as the scherzo seems to go against the implications of the metronome markings—though it's good to see Harnoncourt too observing the scherzo-trio repeat, and once the finale has established itself it's as thrilling as anything else in the set. I have to say that the performance of No. 9 doesn't seem to me quite as consistent as the others: tension in the first movement and the Adagio does flag a little in places. The finale makes up for it though—every long crescendo is like a gradual ascent skywards, and the sections flow into one another beautifully. Even with reservations, this is an exceptional Ninth.

Casting around for a parallel, I have to say that the only recorded cycle I have heard recently in which the musical insight is as consistent and the emotional charge so consistently high is the 1939 Toscanini, currently available on Nuova Era ((CD) 2243/48) but the sound here is far preferable. When this set has had the circulation it deserves, perhaps we'll see an end to that weary lament for the days when conductors were gods, and you could go to a concert and have tea at Lyons Corner House and still have change from a threepenny bit. For those who don't view everything present through black-tinted spectacles this must be one of the most exciting, challenging Beethoven releases to appear in many years.