Tag: tuning

All the notes?

A boy with headphones surrounded by swirling music
Boy listening to music image by Olena from Pixabay

There are infinitely many musical notes, just like there are infinitely many colours. That matters if you are designing a new digital musical instrument. You have a lot more choice than on a piano!

Octaves 

Most Western music is divided equally into groups of 12 notes (‘octaves’) that musicians use. The gap between any two notes sounds the same. This is known as equal temperament tuning. 

Activity: Play the 12 notes 

You can play the 12 notes of an octave on the online piano https://bit.ly/pianoCS4FN. Play Middle C (marked with a red dot), then press each key in turn including the black keys. Play 12 notes and you have played the 12 notes of an octave.

Music as colour

The rainbow picture (below) shows there are many colours to pick from not just red, orange, yellow… A set of crayons would be enormous if it included every possible colour! Instead you get a selection just as in the picture: we picked 3 colours equally spaced apart: red, yellow and blue. Western music does the same thing with sound, picking 12 notes that sound equally spaced.

A spectrum of colour running from red to blue with red, yellow and blue selected equal distances apart
Image by CS4FN

There are lots of other notes that you could sing within an octave. Traditional music often uses different sets of notes. The Arabic system divides an octave into 24 notes, for example. They have more ‘sound crayons’ to play with! You could even start singing on a low note and continually raise your pitch until you reached the higher note, like sweeping through every colour in a musical rainbow.

If you sing a note, then sing the same note but an octave higher (eg Middle C then the next highest C), your vocal cords are now vibrating twice as fast! The frequency of the top note is twice as high as the lower one. Your vocal cords doubled their speed.

Jo Brodie and Paul Curzon, Queen Mary University of London

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The Music and AI pages are sponsored by the EPSRC (UKRI3024: DA EPSRC university doctoral landscape award additional funding 2025 – Queen Mary University of London).

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The day the music didn’t die

An AI generated image of a skeleton wearing a red, blue and yellow sombrero hat, sitting on a stool while playing a guitar against a colourful red and yellow background.
Image by AiRebellion from Pixabay

Computer Scientists are working to support traditional music from around the world.

A seperewa is a traditional “harp-lute” musical instrument of the Akan people in Ghana, Africa. It has strings that are plucked a bit like a guitar. It is dying out because of the rise of western music. Researchers are now testing AIs that were trained on western music to see if they still work with such different seperewa music. They are also trying to understand exactly how this traditional music is different.

Protecting traditional instruments

Colonisers introduced European guitars to Ghana in the late 1800s and their sound began to influence and even replace seperewa music. Worried by this, in the mid-1900s people made recordings to preserve endangered seperewa music and to remind people what it sounds like. Ghanaian musicians are now reviving the seperewa, so we might continue to hear more of its lovely sound in future.

A view of a historical seperewa instrument side-on showing a large sounding box with strings attached to a neck, and stretched taut for playing.
A seperewa, adapted from a public domain image on Wikipedia.

AI to the rescue

A team of computer scientists and music experts have investigated recordings of seperewa music to see how well western AI tools can analyse that style of music, given it is tuned in a completely different way, so plays different notes to a western instrument.

First the team used one AI tool to separate the sounds of the seperewa from the singing. It struggled a bit and left some of the singing in the seperewa track and vice versa but overall did a good job,

They then used a different AI to analyse the sounds of the seperewa. The found that the seperewa music had its own, unique musical fingerprint, revealing a rich tapestry of sound that was clearly different from western music.

The research is helping to preserve a vital part of Ghanaian culture. It has shown in detail how their music is different to anything western and so that something unique and precious would be lost if it died out.

Jo Brodie and Paul Curzon, Queen Mary University of London

Watch …

Hear what a seperewa / seprewa sounds like at this YouTube video: The seprewa – the original African guitar [EXTERNAL]

More on…

We have LOTS of articles about music, audio and computer science. Have a look in these themed portals for more:

Getting technical…

The Music and AI pages are sponsored by the EPSRC (UKRI3024: DA EPSRC university doctoral landscape award additional funding 2025 – Queen Mary University of London).

Subscribe to be notified whenever we publish a new post to the CS4FN blog.