Month: October 2021

Stopping sounds getting left behind: the Bela computer (from @BelaPlatform)

By Jo Brodie and Paul Curzon, Queen Mary University of London

Computer-based musical instruments are so flexible and becoming more popular. They have had one disadvantage though. The sound could drag behind the musician in a way that made some digital instruments seem unplayable. Thanks to a new computer called Bela, that problem may now be a thing of the past.

 

 

A Bela computer surrounded by transistors, resistors, sensors, integrated circuits, buttons & switches. Credit: Andrew McPherson

If you pluck a guitar string or thwack a drum the sound you hear is instantaneous. Well, nearly. There’s a tiny delay. The sound still has to leave the instrument and travel to your ear. The vibration of the string or drum skin pushes the air back and forth, and vibrating air is all a sound is. Your ear receives the sound as soon as that vibrating air gets to you. Then your brain has to recognise it as a sound (and tell you what kind of sound it is, which direction it came from, which instrument produced it and so on!). The time it takes for sound and then your brain to do all that is measured in tens of milliseconds – thousandths of a second. It is called ‘latency‘, not because the delay makes it ‘late’ (though it does!), but from the Latin word latens which means hidden or concealed, because the time between the signal being created and being received, it is hidden from us.

Digital instruments take slightly longer than physical instruments, however, because electronic circuitry and computer processing is involved. It’s not just the sound going through air to ear but a digital signal whizzing through a circuit, or being processed by a computer, first to generate the sound which then goes through air to ear.

Your ear (actually your brain) will detect two sounds as being separate if there’s a gap of around 30 milliseconds between them. Drop that gap down to around 10 milliseconds between the sounds and you’ll hear them as a single sound. If that circuit-whizzing adds 10-20 milliseconds then you’re going to notice that the instrument is lagging behind you, making it feel unplayable. Reducing a digital instrument’s latency is therefore a very important part of improving the experience for the musician.

In 2014 Andrew McPherson and colleagues at Queen Mary University of London aimed to solve this problem. They developed Bela, a tiny computer, similar in size to a Raspberry Pi or Arduino, that can be used in a variety of digital instruments but which is special because it has an ultra-low latency of only around 2 milliseconds – super fast.

How does it do it? A computer can seem to run slowly if it is trying to do lots of things at the same time (e.g. lots of apps running or too many windows open at once). That is when the experience for the user can be a bit glitchy. Bela works by prioritising the audio signal above ALL other activities to ensure that, no matter what else the computer is doing, the gap between input (pressing a key) and output (hearing a sound) is barely noticeable. The small size of Bela also makes it completely portable and so easy to use in musical performances without needing the performer to be tethered to a large computer.

There is definitely a demand for such a computer amongst musicians. Andrew and the team wanted to make Bela available, so began fundraising through Kickstarter to create more kits. Their fundraiser reached £5,000 within four hours and within a month they’d raised £54,000, so production could begin and they launched a company, Augmented Instruments Ltd, to sell the Bela hardware kits.

Bela allows musicians to stop worrying about the sounds getting left behind. Instead, they can just get on with playing and creating amazing sounds.

See Bela in action on YouTube. Follow them on Twitter.

Featured image credit: Andrew McPherson.

 

 

Ada Lovelace: Visionary

Cover of Issue 20 of CS4FN, celebrating Ada Lovelace

By Paul Curzon, Queen Mary University of London

It is 1843, Queen Victoria is on the British throne. The industrial revolution has transformed the country. Steam, cogs and iron rule. The first computers won’t be successfully built for a hundred years. Through the noise and grime one woman sees the future. A digital future that is only just being realised.

Ada Lovelace is often said to be the first programmer. She wrote programs for a designed, but yet to be built, computer called the Analytical Engine. She was something much more important than a programmer, though. She was the first truly visionary person to see the real potential of computers. She saw they would one day be creative.

Charles Babbage had come up with the idea of the Analytical Engine – how to make a machine that could do calculations so we wouldn’t need to do it by hand. It would be another century before his ideas could be realised and the first computer was actually built. As he tried to get the money and build the computer, he needed someone to help write the programs to control it – the instructions that would tell it how to do calculations. That’s where Ada came in. They worked together to try and realise their joint dream, jointly working out how to program.

Ada also wrote “The Analytical Engine has no pretensions to originate anything.” So how does that fit with her belief that computers could be creative? Read on and see if you can unscramble the paradox.

Ada was a mathematician with a creative flair and while Charles had come up with the innovative idea of the Analytical Engine itself, he didn’t see beyond his original idea of the computer as a calculator, she saw that they could do much more than that.

The key innovation behind her idea was that the numbers could stand for more than just quantities in calculations. They could represent anything – music for example. Today when we talk of things being digital – digital music, digital cameras, digital television, all we really mean is that a song, a picture, a film can all be stored as long strings of numbers. All we need is to agree a code of what the numbers mean – a note, a colour, a line. Once that is decided we can write computer programs to manipulate them, to store them, to transmit them over networks. Out of that idea comes the whole of our digital world.

Ada saw even further though. She combined maths with a creative flair and so she realised that not only could they store and play music they could also potentially create it – they could be composers. She foresaw the whole idea of machines being creative. She wasn’t just the first programmer, she was the first truly creative programmer.

This article was originally published at the CS4FN website, along with lots of other articles about Ada Lovelace. We also have a special Ada Lovelace-themed issue of the CS4FN magazine which you can download as a PDF (click picture below).

See also: The very first computers and Ada Lovelace Day (2nd Tuesday of October). Help yourself to our Women in Computing posters PDF (or sign up to get FREE copies posted to your school (UK-based only, please).