A to Z of Engineering: A is for Acoustics

Welcome to Engineer Academy where we’re exploring an A to Z of Engineering – everything from acoustics to zoos.

In each episode, we spin the wheel to find out what type of engineering we’ll be exploring with the help of Engers, our engineering expert.

You can listen to the full series of the A to Z of Engineering here.

Let’s take a look at Acoustic Engineering.

Acoustic Engineering

Acoustic engineering is the branch of engineering dealing with sound and vibration. Acoustical engineers are typically concerned with the design, analysis and control of sound. So that can mean making things heard like making a guitar sound extra loud at a concert or reducing a muffled noise in the background of a recording.

How do we go about creating sounds?

Well, it’s all thanks to pieces of equipment such as amplifiers and speakers. An amplifier takes an input signal from a source such as a laptop, turntable or CD player, and creates a larger copy of that signal before sending it to the speakers, which convert the electrical energy of the audio signal into mechanical sound waves which we can hear.

The volume control is the final bit of the puzzle. This decides how much of current is passed through to the speakers. The higher the volume, the louder it is!!

But what about when we want to reduce the amount of noise? You might have used noise cancelling headphones when travelling or at a concert. They were originally created for pilots to improve their comfort on long flights, and the first consumer versions were also intended for travellers. The technology, known as active noise-cancellation, works by using microphones to pick up low-frequency noise and neutralises it before it reaches the ear. The headset generates a sound that’s phase-inverted by 180 degrees to the unwanted noise, resulting in the two sounds cancelling each other out.

Another place we might want to reduce noise is around construction sites and in factories. Architectural engineers can use sound absorbing materials and designs to help make workplaces, schools and homes much quieter – which is better for our health. There’s a wide variety of materials that are used for soundproofing – from fibre boards and mineral wool to dense foam. As well as in noisy places, soundproofing is also used to improve sound quality in concert halls. And there’s one very clever type of design that can remove sounds almost entirely.

When we talk normally, sound waves bounce off the surfaces all around us – which means we can often still hear people even if they’re in the next-door room. But in something called an anechoic chamber, dense foam in spiked and angled shapes absorb the sound waves as they come out of your mouth – so incredibly, if I was standing right next to you, your voice would sound much quieter. So why might we want to create an environment quite like this? Well, it can be really important when testing audio equipment and also machinery that might be affected by sound waves.

Now, we wouldn’t be able to hear anything without one – well two very important things – our ears! The way we hear is something acoustic engineers take into account when designing ways to make or reduce sounds. Our brains interpret sounds in different ways in different situations – like when you’re at a party, even if there’s a babble of voices, you can still have a conversation with someone nearby because your brain is focusing on their words and not other people’s. And the way we interpret sounds from different types of speakers can change depending on what else is going on or where we are. These psycho-acoustic effects are important factors that engineers take into account.

You’ll find audio engineers in all sorts of areas – as well as noise control, acoustical engineering also covers positive sound – things like ultrasound in medicine, programming digital synthesizers, and even things like railway station sound systems so that people can clearly understand the announcements.

And that’s our take on the letter A – it’s been AWESWOME!

If you would like to check out some other types of engineering, why not check out aerodynamics, aerospace, architectural and automotive engineering!

Join us again next time to spin the wheel and explore another letter in the A to Z of Engineering!