I just wrapped another year working at the Canberra International Music Festival. It’s a 5 day art music festival in May, and I’ve been working there since 2017 – a long, long time. It’s always great to be exposed to so much music in such a small timeframe. A highlight this year was all six of Bach’s Brandenburg Concertos played on period instruments – that is, instruments designed to be like the ones from Bach’s time.

At the venue we were working at, there’s a guitar. One of the workers there had been using piano tunings to tune the guitar. The piano was getting tuned twice a day most days, and his reasoning was that the piano tuner knows more about tuning so he could just copy him. Fair enough. Of course, then we brought in the period harpsichord (a proto-piano) and tuned that. He tried to tune the guitar to the harpsichord tuning, and later, when the piano was being tuned, tried again – and found his guitar was woefully out of tune!

Why does this happen? Well, not all music tunings are equal. Today, almost all music, and certainly the most common music, is equally-tempered. A temperament is a type of tuning system, and the equal means that the notes are evenly distributed. In equal temperament, the octave, which consists of 12 notes, the 7 letters or ‘white keys’ A through G and 5 associated accidentals or ‘black keys’, is divided evenly among these notes, at a ratio of the twelfth root of 2. This means that there is an expected standard among current tunings – you can take a piano from Germany and play it in the USA with no major issues. This is because, in equal temperament, all the notes have standard values. The value of middle A, for instance, is 440Hz (where Hz (hertz) is a measure of sound waves), and one octave higher is 880Hz. These values change slightly around the world – some countries might prefer the slightly sharper or brighter sound of A=442Hz, but even that slight change would not have a noticeable difference to most ears.

In Bach’s time, however, tunings were massively different based on regional centres. You may have heard of Bach’s famous piano work, “The Well-Tempered Clavier”. The clavier is a piano, and being well-tempered meant it was able to play music in any key. Prior to well-temperament, some pianos (or keyboard instruments) could not play in any key as certain notes would sound far too flat or sharp. Being able to play music in any key was a real novelty!

Returning to our harpsichord and guitar dilemma – what went wrong? Nowadays, Baroque orchestras tend to tune to around A=415Hz, which is approximately an A flat in the 440Hz system. So when the harpsichord got tuned and the guitar was tuned with it – it was tuned down much flatter than it normally would be. In fact, he was probably lucky the strings didn’t break from going so low! I also find the concept of an electric guitar tuned to Baroque performance practice quite amusing. Why A=415Hz for Baroque orchestras? It’s a helpful modern equivalent. We do know music in the Baroque period tended to be much lower than A=440Hz, but perhaps not exactly 415Hz. 415Hz works great in a modern system, though, because if you have something which you can’t tune quickly and need on short notice (like a modern piano tuned to 440Hz), then the piano player can just transpose down one note and play the piece as normal otherwise. Easy!

What other music questions have you always had but never knew the answer to? Let me know in the comments below.