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Acoustic treatment is one of the most important aspects of planning and building a room where sound quality and noise control are paramount.

Prime examples are spaces such as recording studios, games rooms, and home theatres.

Without it, you risk excess noise ingress and sound reverberation.

This is why you need to fully understand the concept of acoustic treatment to produce a high end result.

By applying tried and tested methods, you will achieve excellent soundproofing qualities as well as outstanding internal acoustical control.

In the following chapters, we cover various aspects of acoustic treatment.

From understanding the principles of how sound travels and reflects, to how you can deal with poor acoustics and improve overall sound quality.

Click on a chapter below to find out more.

How Sound Travels Around a Room

Below is what generally happens when sound travel around a room:

1. Starting from the source, sound waves project outwards in all directions.
2. A small portion called direct sound, travels in a straight line.
3. The rest of the sound waves, called reflected sound, bounces around randomly between hard surfaces and walls within the room.

Since direct sound has no contact with the room walls because it goes straight towards its recipient i.e your ear, a microphone etc, its frequency balance remains relatively pure with an unaltered tone.

However, each new reflection from reflected sound waves has the ability to change the original sound slightly because it is altered as it impacts against other surfaces.

This change in sound depends solely on the size of the room, and all of the reflective surfaces within.

Therefore, the change in sound is greatly determined by the extent of how much reflection takes place.

Reasons Why Rooms Have Poor Acoustics

There are three main reasons why rooms produce poor acoustics:

Hard Surfaces

Hard surfaces like furniture, bare walls, floors, tables, chairs, and solid objects all affect how sound waves behave.

The more hard surfaces and furniture present, the greater the chances of it bouncing around.

This is because sound waves are not absorbed by hard materials, but rather bounce off these reflective surfaces, potentially creating a noisy and echoey environment.

Multiple Noise Sources

Multiple noise sources combined contribute to poor room acoustics.

People talking and moving and any other environmental noises like machinery, external road noise, air-conditioning and music can combine to create a noise problem.

The cocktail party environment is a prime example of this.

It refers to the difficulty of understanding speech due to the noisy social setting where sounds are produced from multiple sources i.e dozens of people.

High Ceilings

High ceilings are problematic because they offer additional space for sound waves to disappear into.

This creates increased area in a room, resulting in the sound being lost in the extra space above.

This also increases reverberation time, because sound waves have to travel a long way before they are reflected by a hard surface.

Both of these reasons combined mean that high ceilings are generally bad for room acoustics.

What is Acoustic Treatment?

Many people don’t understand acoustics properly because they believe it to be only a concern for musicians, recording studio owners, and theatre halls.

The truth is, acoustics matter in every space, from offices, to museums, to malls. Even football stadiums.

The whole concept of acoustic treatment is based on the fact that many spaces need help to some extent to achieve better sounding acoustics.

Acoustic treatment is an essential solution for spaces with hard surfaces that deflect sound waves and allow them to reverberate throughout.

Whatever the case, these scenarios negatively affect the atmosphere in a building and cause excessive sound reverberation.

For example, if a museum has bad acoustical control, participants of organised tours may find it hard to hear their guide speaking over other sounds such as group conversations, footsteps and external noise.

Acoustic treatment is the solution that will absorb or diffuse sound to improve the acoustic quality of a space.

These treatments take many forms, and some spaces may even need multiple types of treatments applied to achieve the optimum possible sound quality within the space.

Soundproofing vs Acoustic Treatment

Soundproofing and acoustic treatment are two completely different terms.

Soundproofing materials are used when there is a need to minimise the level of sound that travels in and out of a given space by way of creating a physical barrier which would be made up of differing types of materials and construction methods.

• Decoupling by way of creating a stud framing system to minimise direct linkage.
• Internal absorption by adding open cell materials within the framing cavity
• Thermal conversion by way of Acoustiblok Insulation Membrane which converts acoustic energy into heat.
• Deflection by introducing additional mass and density.

This is crucial if you want to create sound levels or noise of a certain volume without the concerns of disturbing adjoining rooms or nearby buildings.

Acoustic treatment on the other hand is applied to minimise sound reflections within the room and create optimal sound quality.

Soundproofing and acoustic treatment both have important roles to play, but you can’t use one to replace the other.

They can of course be used in conjunction with each other.

Absorption & Diffusion

There are two methods to deal with problematic acoustics.

The first method is to stop unwanted frequencies from reflecting into the listening, recording or mixing experience.

This method is called absorption.

Acoustic absorbers are made from materials that prevent sound energy from striking and bouncing off hard surfaces like walls and ceilings.

Acoustic absorbers such as open cell membranes allow soundwaves to enter to trap the reflection, rendering them unable to interfere with the direct sound from the source.

This makes a huge improvement to the quality of sound in your space.

The second method in acoustic treatment is called diffusion.

Diffusion scatters the problematic reflections in different directions which in turn reduces their negative effects.

Acoustic diffusers are made with rigid materials that are arranged in patterns of various sizes, heights, or surface directions.

A combination of the two is generally used in most cases to achieve the necessary results for effective acoustic treatment.

Now that you are aware of the basics of acoustics, you can apply these principles to your space by adding acoustic treatments.

Why is Acoustic Treatment Important

Acoustic treatment has four main goals:

1. To stop standing waves and acoustics from affecting the frequency response of your sound control room i.e cinema, recording studio, office etc.
2. To decrease modal ringing in small rooms, and reduce reverb time in larger spaces such as halls, churches, and auditoriums.
3. To absorb or diffuse sound in the room to stop the ringing and flutter echoes.
4. To reduce acoustic peaks which assists in the prevention of sound leakage.

All the above reasons are why it’s important to employ some form of acoustic treatment.

How to Acoustically Treat Your Room

Reflection

Reflection is generally the most common problem in many rooms.

When sound travels around a room, it will bounce off surfaces such as walls, furniture, and solid objects.

Certain types of surfaces will absorb the sound waves.

Other surfaces will cause the sound waves to bounce off and continue travelling in different directions.

This is a huge problem in areas where you want to control the direction of sound towards the recipient.

Prime examples being auditoriums, cinemas, churches, and concert venues.

If the sound waves are reflecting off other surfaces in the space, they end up missing their target destination.

Reflection also leads to excess reverberation.

Reverberation

Reverberation occurs when multiple sound waves bounce off surfaces and collect together.

This results in a room sounding echoey.

For example, you will hear more reverberation in a large, empty room compared to one filled with more people.

This happens because when people are present, the sound gets absorbed through people’s clothes.

But, if there’s hard surfaces present, sound waves will bounce around continuously.

Another issue reverberation causes is decay in sound quality.

For example, reverberation will interfere when you want people to hear music or a concert.

Even in restaurants, reverberation poses problems since it makes it difficult for diners to converse over the loud, echoey sounds travelling throughout the room.

Resonance

All the objects and materials in a room vibrate at a natural frequency.

For example, a window in a room may vibrate at a rate of 200 Hz.

If a sound wave with a frequency of 200 Hz comes in contact with the window’s surface, it will cause the window to vibrate more violently and the sound will be magnified.

This is the concept of resonance.

This creates acoustical control problems.

Resonance causes sound in a room to come off as “boomy”, a term sound engineers use to describe loud, distorted sounds.

It also causes feedback on sound system recordings.

Types of Acoustic Treatment Application

There are many options that acoustic experts use to fix the issue of reflection, reverberation, and resonance.

Many rooms require a combination of two or more options to address their acoustic issues.

Bass Traps

Low-frequency sound waves are the most difficult to control because they are the longest and the most powerful.

These sound waves also collect in corners and make the bass in a room sound too loud.

This is where bass traps come in handy.

Its function is in its name, since these devices absorb or trap bass sounds at the corner of the room.

There are various types of bass traps you can install depending on the acoustic issues you are facing.

Some traps can also trap mid or high frequencies.

They are made from porous materials like rigid fibreglass and foam that effectively absorb sound waves into room corners.

Acoustic Panels

Acoustic panels serve a similar purpose as bass traps, by absorbing sound waves.

They are generally thinner than bass traps, making them less effective at trapping lower frequencies.

They can still make a significant improvement to spaces where reverberation is an issue however.

Acoustiblok’s Acoustic Absorber Panels absorb sound waves rather than allowing them to reflect off hard surfaces.

Acoustic panels are also visually pleasing compared to bass traps, which tend to be a bit more conspicuous.

You can mount acoustic panels anywhere in a room, but they are usually hung on walls.

Since acoustic panels commonly look like artwork, they are far less noticeable and can be seen as part of a room’s decoration.

Acoustiblok Acoustic Absorber Panels are also available with your own unique high-resolution images using bespoke printing, for an extra special custom look and feel.

Acoustic Clouds

Some acoustic panels are created to be installed on the walls, while some are specifically created for ceilings.

Acoustic panels for ceilings are called acoustic clouds.

They are lightweight, allowing them to be suspended horizontally from the ceiling.

Acoustic clouds are especially useful for buildings that have high ceilings.

High ceilings are an attractive architectural feature but unfortunately contribute to excessive sound reverberation.

You may have come upon a contemporary, modern-looking ceiling in a building and didn’t realise that the suspended panels were installed to improve the room’s acoustics.

There are many acoustic ceiling panels available on the market, and one that offers excellent performance is the range of Acoustiblok AcoustiCloud Absorber Panels ceiling panels.

Aside from having excellent acoustic results, they are also visually pleasing to enhance the appearance of a room.

These panels are manufactured in a wide range of sizes, shapes, styles and colours, making them easy to blend into any internal decorative environment.

Acoustiblok AcoustiCloud Absorber Panels are also available with your own unique high-resolution images using bespoke printing, for an added custom look and feel.

Acoustiblok AcoustiCloud Absorber Panels provide acoustic treatment to areas that use thermal mass construction by allowing the air to flow freely in the room.

They are designed to absorb sound from the front, edge, as well as rear surfaces where suspended away from the ceiling. This results in the highest sound absorption performance across differing frequencies, including problematic low frequencies.

Acoustiblok’s Acoustic Absorber Panels and AcoustiCloud Absorber Panels are available in 40mm deep panels with a Class A absorber, and 25mm deep panels for a thinner profile on a wall.

They are quick and easy to fit, and do not require a specialist installer.

Diffusers

Diffusers are designed with the intent to diffuse unwanted sound.

In some cases, people want to prevent sound waves from causing echo without fully absorbing the sound, so the room doesn’t end up sounding too ‘dead’.

In cases like above, diffuser panels are the ideal acoustic treatment.

These are three-dimensional panels, with pieces protruding in different directions allowing sound waves that impact the diffuser to scatter in random directions.

So, while sound absorption treatments generally remove sound energy, diffuser panels help to keep the space sounding ‘alive’.

You can use these in place of sound absorbing treatment or to complement them.

Acoustic Foam

Acoustic foam can be used in a similar way as acoustic panels.

But whereas acoustic panels come in a ready-made form to hang on the walls and have visual appeal, acoustic foam comes in raw material form.

They are typically used in recording studios that require acoustic treatment.

Acoustic foam looks similar to egg boxes while acoustic panels are smooth.

This is why acoustic foam is mainly used for more practical, heavy-duty acoustic treatment, rather than lighter treatments for spaces like restaurants or meeting rooms.

You can place acoustic foam on walls and ceilings to trap sound.

Acoustic Membrane

There are many acoustic membranes on the market, with some having better soundproofing and acoustical control qualities than others.

But the best performing material by far is Acoustiblok Insulation Membrane.

Installing an Acoustiblok Insulation Membrane within the construction of walls, floors and ceilings helps to stop sound from moving through the building structure, flanking paths and cavity.

Due to its extremely thin and high performance rating, it is highly effective in numerous applications with its core principle being thermal conversion from acoustic energy.

Available in both 3mm and 6mm thicknesses, it is generally installed in walls, ceilings, and floors to decrease airborne and impact noise.

Incredibly, it is more effective than a sheet of lead in blocking sound transfer, so is perfect for sound insulation.

Because it’s polymer-based, it is very flexible, adaptable, and easy to install.

It effectively isolates sound waves without increasing the thickness of walls or ceilings, or by filling them with excess mass.

There are other rubber compounds filled to increase mass and density but these are much heavier and rely greatly on deflective principles.

Helmholtz Resonators

If you have ongoing resonance issues, Helmholtz resonators are the solution.

Its name is derived from the German physicist who invented them.

It is a hollow sphere with a small opening protruding from the top, the same as a bottle or a vase.

The important thing to keep in mind for acoustic treatment is that Helmholtz resonators can absorb sound that have a similar frequency.

You can use resonators of different shapes and sizes to absorb different frequencies.

This way, you can target specific frequencies that are excessive in space.

By absorbing these specific frequencies, you can counteract the problem directly.

Even though Helmholtz resonators are not a popular means of acoustic treatment, they are handy in certain situations.

Conclusion

Achieving optimum room acoustics can seem like a complicated process, with several solutions available to address the issues.

Hopefully, this article will have cleared up some of the mystery surrounding acoustic control and which methods are best applied for your situation.

However, if you’re still confused or unsure of how to approach your own project, contact us today to speak to a member of our technical team.