Classical music is something often associated with tradition and continuity, rather than innovation, and it can therefore sometimes be assumed that not much has changed over the centuries.

However, in the same way that the forms and styles of music have changed over the years (Bach’s music being rather different to Mahler’s), other things have too. And one of those things is the instruments themselves, and indeed the way they are played.

Of course some instruments have come and gone, the theorbo for example. And some have come into being in more recent times. But some have been staples for centuries – stringed instruments such as the violin and cello for example, or the piano. And to the casual observer, they look pretty much the same as they always did…but that’s not quite true.

Even though the changes can be subtle, musical instruments and how their playing styles have changed, sometimes dramatically. Take the violin – it’s evolved over time into the instrument we know today. But the violin Bach would have known is quite different to the violins that are made now.

Look at the bow for example – todays bow has a concave shape, the wood bending towards the hairs along the length, whereas Baroque bows (from the time of Bach or Handel) are shorter and have a convex shape – bending outwards, away from the hairs. The playing style of each is quite different, and so is the sound produced.

And the strings that are used are entirely different. Today’s instruments use entirely metal strings, but in past centuries animal gut was used – again changing the sound and requiring (a lot) more tuning as they’re far more susceptible to changes in heat and humidity.

Now look at the piano. Its ancestor was the fortepiano (literally, the ‘loud soft’). The fortepiano is of much lighter construction than today’s modern pianos, and whereas modern pianos are built for consistency across the notes, you’ll find much more variation in sound from the deepest notes of the fortepiano to the highest notes – more buzzy in the bass and more tinkly in the higher range. It’s also just a good deal less loud than the modern instrument, more part of the texture of a concerto rather a dominant solo instrument.

What’s interesting about all of this is of course that composers were writing for instruments of their day, not for modern instruments. Mozart never expected his piano concertos to be played on the muscular instruments we know now, and perhaps he might have written them differently if he had.

Over the last 40-50 years the ‘Historically Informed Performance’ (HIP) movement has sprang up – dedicated to reviving those instruments and playing styles and perhaps getting us just a little closer to the sounds the composer intended. Having at first been seen as the ‘hippies’ of the classical music world, it’s ended up being a highly influential movement, changing playing styles right across classical music. It’s not been without controversy – many hated the idea of stringed instruments being played without vibrato for example, something not done in the past – but orchestras like the Orchestra of the Age of Enlightenment and Academy of Ancient Music are now mainstream rather than fringe and very much a core part of the classical music scene.

At this years Festival we’re we’re hosting three performances all played on what are known now as ‘period’ instruments. Tonight (21 Aug), the brilliant fortepianist Kristian Bezuidenhout gives us a rare chance to hear Mozart played on the instrument – and it really is quite different. He’s joined on stage by the Consone Quartet, playing on gut strings. Tomorrow (22 Aug) you can hear Beethoven played on period instruments with the Chiaroscuro Quartet and following that one of the greatest of Baroque violinists and a leading light in today’s ‘HIP’ scene, Rachel Podger, joins us for late night Bach.

It promises to be a fascinating set of performances, and the appearance of Steven Osborne playing Beethoven on a modern piano this Saturday (23 Aug) gives an interesting chance to compare and contrast too.

Browse all Festival performances here.