At a Gaudier Ensemble rehearsal last week my colleagues, who come from various European countries, were discussing the unstoppable rise in pitch. Here in England we still tune to A=440 Hz, which has been ‘standard pitch’ since the mid-twentieth-century, though in the rest of Europe standard pitch has gradually become somewhat higher, at A=444 or even A=445. Even in the UK, it’s increasingly the case that a higher A is used at the request of visiting artists.  Of course this must be a major pain for piano tuners, who sometimes have to tweak the entire piano by a tiny fraction, and back again to A=440 when the visiting artist has gone. Alternatively, a concert hall has to keep two pianos, one tuned to A=440 and the other to A=444.

I asked my string-playing friends from mainland Europe whether they prefer playing with a higher A? They all said no, adding wistfully that their instruments resonate more freely and sound better with a lower A. So what’s driving the inexorable rise in pitch? In psycho-acoustical terms, there seems to be a feeling that playing sharp adds brilliance to the tone. My friends said that in orchestras they notice that when the wind players are playing a little sharp, the string players discreetly tune up to match them, and so the whole vicious circle goes on. Amongst orchestral players there’s a rueful saying, ‘Better sharp than out of tune’. We agreed that the constant rise in pitch is mysterious, given that no-one appears to be pushing for it, and moreover that it doesn’t seem to benefit anyone, certainly not the lovely old instruments built when an even gentler A was in use.

This morning in the village church of Cerne Abbas, we invited the children of the local primary school to come and listen to a rehearsal of Aaron Copland’s attractive piece, Appalachian Spring (part of tonight’s concert programme). It lasts around 25 minutes, quite a long while for young children to sit quietly, which they did. Towards the end of the piece, Copland brings in the lovely Shaker hymn ‘Simple Gifts’ with its well-known words, ”Tis a gift to be simple, ’tis a gift to be free’.

I was playing the piano at the back of the ensemble and was turned at right angles to the audience, so I couldn’t see them, but suddenly I heard what sounded like an angelic choir singing along with ‘Simple Gifts’, perfectly in tune. I turned to my right to see all the children unselfconsciously singing along with us, their little faces seriously raised towards the stage. It was a most beautiful effect, a choir of young children suddenly added to the instrumental ensemble, and I must say I had tears in my eyes. Had Copland been in the church he might have wanted to rewrite the piece and add a choir of children to his original score. But of course what made it particularly sweet this morning was that their contribution was spontaneous, unrepeatable.

I’m in rural Dorset to take part in one of those thriving summer music festivals never mentioned in the Guardian’s guide to same. This will be the 21st annual festival run by the Gaudier Ensemble; I’ve been ‘at the piano’ for eighteen of those years. Despite the silence of the music press, the festival continues to flourish and to attract a loyal audience not only from this part of England, but sometimes from much further afield.

Rehearsals in the church are open to the public, and there have been people listening to every rehearsal so far, sometimes sitting in the church until late into the evening to catch all the pieces being worked on. Tonight is the first of seven concerts, and from now until Sunday evening we cover an enormous range of repertoire, from Mozart and Beethoven through Glinka, Rimsky-Korsakov and Tchaikovsky to Dohnanyi, Copland and Barber. One of the things I like is that this is not a specialist audience, nor has this village thrown its allegiance behind classical music, but everyone is willing to give our concerts a go, and having done so, they generally return time after time. This means that we see the same people in the audience year after year, a reunion I particularly look forward to.

We have a pair of resident blackbirds in our garden, and every day the male blackbird perches on the chimney and sings loudly, especially at dusk. He seems to have several ‘songs’ or sequences of phrases which he sings over and over. I’ve heard them hundreds of times, but although I’m a musician and quite good at picking up things by ear, I can never do more than repeat fragments of the blackbird’s song. I certainly can’t whistle the whole song, or even several phrases in a row. They are so intricate, the oscillation between notes is so fast, and the tuning is so … well, so avian, that it baffles my human ear. Many of the pitches seem to fall into the tiny cracks between semitones. I can recognise the shape of phrases and their sequence, but the detail and the precise tuning seem constantly to be just beyond my ability to imitate them.

I can see why some composers have been fascinated by birdsong – famously, of course, Messiaen, whose pieces are full of the cries and calls of exotic birds as notated by him. Perhaps there are some birds whose song can be pinned down in pitches and rhythms familiar to the human ear, but the blackbird’s song would challenge any system of notation that I know about. To write something down, you have to be able to analyse its pitch and rhythm, and our blackbirds have remained serenely inscrutable.

An interesting discussion with students about whether it’s right to ‘scale things up’ to 21st century tastes when playing 18th/19th century music. They had played Beethoven so powerfully and with such speed and ringing ‘attack’ that I found myself wondering whether they had converted the music into something that would have startled the composer. I said it was important to remember what ‘loud’ would have seemed like to someone writing for delicate instruments more limited in scope. And to remember how the instruction to play ‘fast’ might have been meant by someone whose idea of ‘fast’ was probably determined by things like galloping horses – not Formula One racing cars.

My students countered with the idea that if Beethoven were alive today, he would enthusiastically have embraced the possibilities of bigger, louder pianos, and string instruments with stronger bows, louder strings, and more projecting power. In a way, I agree with them, and I often really enjoy performances which use the full dynamic range of modern instruments, thereby revealing more of the music’s emotional range.

On the other hand, I increasingly feel it’s a mistake to act in ignorance of what Beethoven and his friends would have heard when they sat down to play chamber music together, and how those familiar sounds would have matched the musical content. It sometimes seems to me that there comes a point when the ‘upgrade’ to 21st-century sonorities actually obscures some of the musical points, rather than enhancing them.