Beginner's Guide to Acoustics: 10 Key Terms Explained

Trying to tackle acoustics problems without even knowing the basic terms will leave you feeling lost and confused, as if you are in a mirror maze. Talk about reflections… If you are living in a cathedral and you are not the pope, then maybe you have acoustic issues. Or perhaps you just want to make your speech clearer during Zoom calls. Whatever the case, if you’ve ever tried to fix a room’s acoustics, you’ve probably bumped into a bunch of terminology.

Acoustics is a science, but we can crack open the doors of perception with some useful examples and explanations. It is essential to comprehend how sound behaves and its interactions with the surrounding environment. Once you get the basics of acoustic performance, you can stop guessing and start actually improving your space.

 

Decibels (dB)

 

Decibels are a way to measure how loud something is. Sound can be ridiculously quiet, like a whisper, or ear-splittingly loud, like a concert. Decibels help us compare all these extremes on a scale that our brains can handle. Measuring decibels can be tricky to comprehend because they do not scale gradually, which means that a 70 dB sound can feel twice as loud compared to a 60 dB sound.

A normal chat is around 60 decibels. And a busy street might be 70 decibels. The difference hits you noticeably harder. Knowing what decibels mean helps when someone tells you a panel “reduces noise by 10 dB.” You’ll immediately know that’s a meaningful improvement.

 

 

Sound wave

 

A sound wave is the way sound travels through the air. Picture tiny ripples moving out from the source, carrying energy - pitch, volume, and tone.

When you speak, your vocal cords push air, creating these waves. They travel across the room, hit walls, furniture, or curtains, and reach someone else’s ear. Everything in a room interacts with these waves. If you imagine sound like water waves hitting a rock or floating past a log, it’s easier to understand why some surfaces soak it up while others bounce it around.

 

Airborne noise

 

Airborne noise is simply sound travelling through the air. Voices, music, ventilation hum, traffic outside, that’s all airborne noise.

Ever hear your loud upstairs neighbour’s TV, or someone talking in the next room? That’s airborne noise sneaking through walls and floors. Knowing whether the noise is airborne or coming through the structure (like the floor or walls) is crucial because it tells you how to tackle it. Panels and curtains help with airborne noise, while structural noise might need more serious solutions.

 

Absorption

 

Absorption is when a material soaks up sound instead of letting it bounce around the room. Think of it as a sponge that traps sound inside and quietly leaves it to disappear. Soft, porous materials do this best. 

A thick carpet, a heavy curtain, or foam panels on the walls. They all absorb sound waves, making a room feel less echoey. If your living room sounds like a tiny concert hall, absorption is your friend. 

 

 

Diffusion

 

Diffusion is all about spreading sound out instead of letting it bounce straight back. It stops harsh echoes and makes a room sound more balanced.

For example, some studios have panels with skyline surfaces. They scatter sound in different directions so no part of the room is too boomy. Diffusion is handy when you don’t want to kill all reflections; it keeps a room lively while taming the worst echoes.

 

Reverberation

 

Say reverberation three times in a dark and empty room, and you will understand what it is. It is the lingering sound you hear after the original noise has stopped. It’s the result of sound bouncing around walls, floors, and ceilings.

Clap your hands as if you are giving a sarcastic ovation in a large hall and hear them “ring” for a few seconds. That’s reverberation. Too much and speech becomes a muddle, too little and the room feels dead. Understanding reverberation helps you decide how much absorption or diffusion a space needs.

 

Echo

 

An echo is a distinct repeat of a sound that comes back to your ears after a noticeable delay. Unlike general reverberation, an echo feels like a second sound.

Shout in a canyon and hear your voice bounce back. That’s a perfect echo. In rooms, echoes are usually unwelcome because they are distracting. The goal is to avoid surfaces or angles that create those obvious repeats.

 

 

Background noise

 

Background noise, or ambient noise, is the constant, unwanted hum in a space.

The whir of an air-conditioning unit, traffic outside, your co-workers' quiet music from a laptop, or even a buzzing fridge – all of it contributes. If the background noise is too loud, it can mask quieter sounds you actually want to hear. Acoustic improvements aim to bring reflections below this “noise floor” so that important sounds come through clearly.

 

Acoustic panels

 

Acoustic panels are designed to either absorb or diffuse sound. They are the tools that help you shape the way a room sounds.

You will often see them in offices, studios, or home cinemas. Fabric-wrapped panels on the walls or ceilings reduce echo and make speech easier to understand. When choosing panels, think about what frequencies they absorb and how that matches the room’s needs. Not all panels work for every problem.

 

 

Bass

 

Bass refers to low-frequency sounds, the deep tones you feel in your chest. These waves are long and powerful, which makes them harder to control than higher-pitched sounds.

Think of the thump of a subwoofer or the low rumble in a cinema. Regular panels often struggle with bass, so if low frequencies are causing issues, you might need bass traps or specialised low-frequency treatments.

Knowing acoustic terminology gives you clarity and confidence. When you understand terms like absorption, reverberation or diffusion, you can interpret specs, compare products and make informed choices rather than relying on guesswork.

Ready to speak acoustics fluently? Contact DECIBEL today for bespoke advice, spec checks or acoustic design support.