Which Acoustic Panels Absorb the Most Sound?

The acoustic panels that absorb the most sound are usually well-designed porous panels with strong independently tested performance across the frequencies that matter to the room.

Thick fabric-wrapped panels with mineral wool or glass fibre cores often provide good broad-frequency absorption. Suspended rafts and baffles can also deliver strong performance because sound reaches more than one face.

However, material alone does not determine which panel is best.

Performance also depends on:

• Panel thickness
• Density and internal structure
• Distance from the wall or ceiling
• Mounting arrangement
• Surface finish
• The frequencies being assessed
• The amount of treatment installed
• Where the panels are positioned

A thin foam tile and a thick fabric-wrapped panel may both be described as “acoustic”, but they are unlikely to perform in the same way.

The safest approach is to compare properly tested acoustic data for the complete panel system, rather than choosing by appearance, material or marketing description alone.

What do acoustic panels do?

Acoustic panels absorb some of the sound energy that would otherwise reflect from the walls, ceiling or other hard surfaces within a room.

They can help reduce:

• Reverberation
• Echoes
• Noise build-up
• Poor speech intelligibility
• Harsh reflections
• The distance over which distracting sound travels

Acoustic panels are commonly used in:

• Offices
• Meeting rooms
• Classrooms
• Restaurants
• Reception areas
• Sports halls
• Recording studios
• Auditoria
• Hotels
• Healthcare spaces
• Community buildings
• Places of worship

Their main purpose is normally to improve how sound behaves within the room.

They do not automatically prevent sound passing into the room from outside or travelling through a wall to a neighbouring space.

Sound absorption and soundproofing are different

This is the most important distinction to understand before buying acoustic panels.

Sound absorption

Sound absorption reduces reflections within a space.

It can make the room:

• Less echoey
• Easier to hold a conversation in
• More comfortable
• Better suited to teaching or meetings
• Clearer for music or announcements

Acoustic panels, rafts, baffles and absorptive ceilings are examples of products used for this purpose.

Sound insulation

Sound insulation reduces sound travelling between separate rooms or through the building envelope.

It may require measures such as:

• Heavier or multi-layered walls
• Isolated wall linings
• Improved doors
• Secondary glazing
• Sealed penetrations
• Floating floors
• Resilient ceiling systems
• Control of flanking transmission

Adding absorptive panels to a noisy office may reduce reverberation, but it will not necessarily stop conversations being heard in the next room.

A project may need absorption, sound insulation or a combination of both.

How is acoustic-panel performance measured?

Acoustic products should be compared using tested performance data.

In the UK and Europe, sound absorption is commonly measured in a reverberation room under BS EN ISO 354:2003. The test establishes absorption across a series of frequency bands, and the results can be used for product comparison and room-acoustic design. ISO reviewed and confirmed the standard in 2024.

The exact specimen and mounting arrangement matter. A panel fixed directly to a surface may produce different results from the same panel suspended below a ceiling or installed with an air space behind it.

The published test report should therefore identify how the product was installed during testing.

What is the sound absorption coefficient?

The sound absorption coefficient describes the proportion of incident sound energy absorbed by a material or system at a particular frequency.

A value closer to zero indicates low absorption, while a value closer to one indicates high absorption under the test conditions.

However, one material rarely absorbs every frequency equally well.

A panel may perform strongly at frequencies associated with speech but provide much less absorption at lower frequencies. This is why the frequency-by-frequency test results are often more useful than one headline number.

The original article suggested that any sound not absorbed must simply be reflected or transmitted. In practice, the measured behaviour depends on the complete test specimen, its mounting and the surrounding conditions. The rating should therefore be interpreted as test data for that system rather than a simple description of the raw material.

What is an αw rating?

αw, pronounced “alpha w”, is the weighted sound absorption coefficient.

BS EN ISO 11654 converts frequency-dependent absorption data measured under ISO 354 into a single-number rating. It also provides the basis for acoustic absorption classes. The current UK version is BS EN ISO 11654:1997, which BSI lists as current and under review.

A higher αw value normally indicates stronger overall sound absorption.

Products may also be placed into classes running from:

• Class A: highest classified absorption
• Class B
• Class C
• Class D
• Class E: lower classified absorption

The class is useful for quick comparison, but it does not tell you everything about the product.

Two panels with similar αw ratings may perform differently at low, middle or high frequencies.

For rooms with specific acoustic problems, the full frequency data should be reviewed.

What is NRC?

NRC, or Noise Reduction Coefficient, is another single-number sound absorption rating.

It is commonly used in North America and is produced from testing under ASTM C423. The current standard is ASTM C423-23e1.

NRC and αw both summarise sound absorption, but they use different calculation and classification methods.

They should not be treated as directly interchangeable.

For a UK project, αw and the absorption class may be more familiar to the design team. Where a product provides only NRC data, the test report should be reviewed carefully rather than assuming that an NRC value equals the same αw result.

Which panel material absorbs the most sound?

There is no single material that is always best.

Different panel systems can achieve strong results when they are designed, tested and installed correctly.

Fabric-wrapped mineral wool or glass fibre panels

Fabric-wrapped porous panels are among the most common choices for controlling reverberation.

Their cores may be made from:

• Mineral wool
• Glass wool or glass fibre
• Other fibrous acoustic materials

Sound enters through the acoustically transparent fabric and interacts with the porous core, where part of its energy is dissipated.

These panels can offer:

• Strong broad-frequency absorption
• A wide choice of sizes and colours
• Printed or customised finishes
• Wall or ceiling installation
• Relatively discreet integration into interiors

Thicker panels and panels installed with an air gap can often provide better lower-frequency absorption than thin panels mounted directly against a wall.

However, the result depends on the complete tested system.

Do not assume that every mineral-wool or glass-fibre panel has the same performance.

Polyester and PET felt panels

Polyester-fibre panels are widely used in offices, education, hospitality and interior fit-outs.

They may be supplied as:

• Flat wall panels
• Ceiling rafts
• Vertical baffles
• Freestanding screens
• Desk dividers
• Decorative shapes
• Slatted or folded products

They can be lightweight and design-friendly, but performance varies considerably according to thickness, density, shape and mounting.

A thin decorative felt panel may provide useful mid- and high-frequency absorption while offering less control at lower frequencies.

Look for tested data for the exact product and installation rather than relying on a generic claim that PET is “highly acoustic”.

Acoustic foam

Open-cell acoustic foam can absorb reflected sound, particularly at middle and higher frequencies.

It is often associated with:

• Recording rooms
• Rehearsal spaces
• Podcast rooms
• Small studios
• Domestic media rooms

Foam panels can be light and relatively easy to install.

However, thin foam products may offer limited performance at lower frequencies. Decorative wedge or pyramid shapes do not necessarily mean the product absorbs more sound than a plain panel of comparable material and thickness.

Foam should also be selected carefully for:

• Reaction to fire
• Durability
• Surface damage
• Ageing
• Cleaning
• Suitability for the building type

A low-cost product without suitable test evidence should not be assumed to be appropriate for a commercial or public building.

Perforated or slotted timber panels

Timber acoustic panels can provide an attractive finish where the design team wants to retain a harder, more architectural appearance.

The timber facing is normally perforated, slotted or spaced so sound can pass through to an absorptive layer and cavity behind it.

The performance comes from the complete system, which may include:

• The timber facing
• The percentage of open area
• Hole or slot dimensions
• Absorptive backing
• Cavity depth
• Panel thickness
• Mounting arrangement

A solid timber panel without suitable openings and backing is primarily reflective rather than absorptive.

Perforated or slatted timber systems may be useful in:

• Auditoria
• Lecture theatres
• Offices
• Hospitality spaces
• Reception areas
• Performance venues
• Education buildings

They can combine visual quality with acoustic performance, but they should be specified from tested system data.

Perforated metal panels

Perforated metal panels work on a similar principle.

The metal surface allows sound to reach an absorptive backing or cavity.

They can be suitable where the project needs:

• Robustness
• Cleanability
• A particular visual finish
• Integration with ceilings or wall systems
• Resistance to physical damage

As with timber systems, the perforated facing alone is not normally the main absorber. The open area, backing material and cavity all affect performance.

Wood-wool panels

Wood-wool panels combine wood fibres with a mineral binder.

They can provide a textured architectural finish and may offer:

• Sound absorption
• Physical robustness
• A distinctive visual appearance
• Integration into walls or ceilings

Their absorption performance depends on the product thickness, mounting and whether an additional absorptive layer or cavity is used.

The test data should be reviewed in the same way as for any other panel.

Ceiling rafts and acoustic baffles

Rafts and baffles are suspended within a room rather than fixed continuously to a surface.

This allows sound to reach multiple faces, potentially increasing the equivalent absorption provided by each object.

They can be useful where:

• The existing ceiling must remain visible
• Services prevent a full acoustic ceiling
• The room has a large volume
• The design calls for suspended features
• Wall space is limited
• Treatment needs to be distributed throughout the space

Individual suspended objects may be assessed using equivalent sound absorption area rather than the same square-metre coefficient used for a continuous plane absorber.

ISO 20189:2018 sets out how screens, furniture and individual interior objects can be assessed and distinguishes between plane absorbers and discrete objects.

This means a raft or baffle result should not always be compared directly with a flat wall-panel rating without considering how the test data is expressed.

Which acoustic panel is best for low-frequency sound?

Low-frequency sound is generally more difficult to absorb using thin panels.

Potential low-frequency problems may include:

• Bass-heavy music
• Mechanical plant
• Large-room resonances
• Studio monitoring
• Low-frequency noise build-up

Possible approaches include:

• Thicker porous absorbers
• Larger air spaces behind panels
• Deep ceiling rafts
• Corner-mounted treatment
• Membrane absorbers
• Resonant absorbers
• Bass traps designed for a particular frequency range

These systems need more depth and careful design than a thin surface-mounted panel.

A panel with an excellent headline αw rating may still provide limited absorption at the specific low frequency causing the problem.

The frequency-band data is therefore essential.

Does thicker mean better?

Increasing panel thickness can improve absorption, particularly towards lower frequencies.

However, thickness is not the only factor.

Performance also depends on:

• Material structure
• Airflow resistance
• Density
• Surface covering
• Mounting
• Air cavity
• Panel dimensions
• Frequency
• Edge exposure

A thicker panel is not automatically better if it has not been designed or installed appropriately.

Similarly, a very dense material is not necessarily more absorptive. Materials that are too closed or rigid may reflect sound rather than allowing it to enter the absorber.

The tested result remains more reliable than assumptions based on weight or thickness alone.

Does an air gap improve acoustic-panel performance?

An air space behind a porous panel can improve absorption at lower frequencies.

This is one reason suspended rafts and spaced wall panels may perform differently from panels fixed directly against a hard surface.

The size of the benefit depends on:

• The panel
• The depth of the gap
• The frequencies involved
• The mounting arrangement
• The room

The test result should match the proposed installation.

If a manufacturer’s strong rating was achieved with a large air cavity, installing the same panel directly onto a wall may not reproduce that performance.

Is Class A always the best choice?

A Class A absorber provides high overall absorption, but it is not automatically the right product for every space.

The design also needs to consider:

• The amount of treatment required
• Where it will be placed
• The frequency range
• Durability
• Cleaning
• Fire performance
• Visual design
• Impact resistance
• Moisture
• Fixing and maintenance
• Cost
• Sustainability
• The room’s intended acoustic character

Installing too much high-performing absorption can make some rooms feel acoustically flat.

The aim is to achieve appropriate room conditions, not simply to specify the highest possible rating everywhere.

How many acoustic panels does a room need?

There is no reliable universal answer based only on the room’s floor area.

The amount of treatment depends on:

• Room volume
• Existing finishes
• Ceiling height
• Furniture and occupancy
• Current reverberation time
• Target reverberation time
• Panel performance
• Mounting arrangement
• Room use
• Distribution of the treatment

A calculation or acoustic model can estimate the amount required.

For an existing space, reverberation measurements can establish the current performance and help determine how much additional absorption is needed.

Simply covering an arbitrary percentage of the walls may lead to too little treatment, unnecessary expense or poor distribution.

Where should acoustic panels be installed?

Position can be as important as quantity.

Possible locations include:

• Ceilings
• Upper wall areas
• Rear walls
• Walls near noisy activity
• Between work zones
• Opposite strong reflective surfaces
• Around teaching or presentation areas
• Suspended above open-plan spaces

Treatment should normally be distributed rather than concentrated in one small area.

In some rooms, the placement is guided by:

• Reflection paths
• Sound-system positions
• Room geometry
• Speaker and listener locations
• Workstation layout
• Existing finishes
• Available ceiling space

Aesthetic symmetry does not always produce the best acoustic result.

Can curtains, carpets and furniture replace acoustic panels?

Soft finishes can contribute to a room’s overall absorption.

Carpet may reduce some high-frequency reflections and impact noise from footsteps. Curtains and upholstered furniture can also affect reverberation.

However, their performance may be:

• Difficult to quantify
• Limited at lower frequencies
• Dependent on thickness and construction
• Variable as furniture or curtains move
• Insufficient for rooms with demanding targets

They should be included in the acoustic assessment, but they may not provide enough control on their own.

Purpose-designed acoustic panels offer more predictable performance when supported by suitable test data.

What should you check before choosing acoustic panels?

Do not choose a panel solely because it is described as “soundproof”, “noise reducing” or “studio grade”.

Check the following.

Independent acoustic test data

Look for results from an appropriate test method, normally BS EN ISO 354 for absorbers used in UK buildings.

The αw rating and absorption class

These provide a useful initial comparison under BS EN ISO 11654.

Frequency-band performance

Check whether the panel performs well at the frequencies relevant to the problem.

The tested mounting arrangement

Confirm whether it was:

• Fixed directly to a surface
• Installed with an air gap
• Suspended
• Used with additional backing
• Tested as a continuous area
• Tested as an individual object

Panel thickness and dimensions

Make sure the product quoted matches the tested configuration.

Reaction to fire

Products used in buildings may need a suitable reaction-to-fire classification for their location and application.

BS EN 13501-1 provides the UK classification procedure for construction products using reaction-to-fire test data. The required classification depends on the building, product use and applicable fire strategy.

Durability and maintenance

Consider:

• Impact resistance
• Moisture resistance
• Cleaning
• Surface damage
• Fibre containment
• Replacement
• Access to services

Environmental information

Claims about recycled content, recyclability or sustainability should be supported by product-specific evidence.

Do not assume every mineral-fibre, foam, timber or PET panel has the same environmental credentials.

Common mistakes when choosing acoustic panels

Common problems include:

• Choosing by material rather than tested performance
• Comparing αw directly with NRC
• Looking only at the single-number rating
• Ignoring low-frequency performance
• Installing the panel differently from the test arrangement
• Assuming decorative felt is always highly absorptive
• Treating acoustic foam as soundproofing
• Using solid timber panels without an absorptive system
• Buying insufficient treatment
• Concentrating all panels in one area
• Ignoring reaction-to-fire requirements
• Over-treating a room
• Installing panels without first understanding the acoustic problem

Do acoustic panels reduce noise from neighbours?

Not usually in the way people expect.

Panels may reduce reverberation in your room, which can make the space feel calmer and reduce the overall build-up of sound.

However, they will not normally provide a substantial improvement to sound insulation through a shared wall, ceiling or floor.

Noise from neighbouring premises may require investigation of:

• The separating construction
• Flanking paths
• Doors
• Windows
• Gaps and penetrations
• Floors and ceilings
• Building services
• Structure-borne sound

Adding foam or wall panels to one side of a lightweight wall is unlikely to solve a significant sound-transfer problem.

Do acoustic panels reduce noise leaving a room?

They may make a small contribution by lowering the reverberant sound level within the source room.

However, the main sound-insulation performance is still controlled by the building envelope and separating constructions.

A music room, nightclub, plant room or studio may need:

• High-performance walls
• Independent linings
• Acoustic doors
• Sealed ventilation systems
• Floating floors
• Isolated ceilings
• Vibration control
• Careful junction detailing

Acoustic panels may form part of the internal room treatment, but they are not a substitute for a suitable sound-isolation design.

Which acoustic panels should you choose?

For many offices, classrooms, meeting rooms and hospitality spaces, a well-tested porous panel or ceiling system with suitable broad-frequency absorption can be a good starting point.

However, the final choice should reflect:

• The acoustic target
• The frequencies causing the problem
• The amount of absorption needed
• The available mounting depth
• The design intent
• Fire and maintenance requirements
• The room’s use
• The budget

The “best” acoustic panel is therefore not simply the softest, thickest or most expensive option.

It is the panel system that provides the required tested performance, can be installed in the intended way and forms part of a properly designed room-acoustic strategy.

Why involve an acoustic consultant?

An acoustic consultant can help establish whether acoustic panels are actually the right solution.

This may involve:

• Measuring reverberation time
• Assessing background noise
• Identifying strong reflections
• Reviewing speech intelligibility
• Setting an appropriate target
• Calculating the absorption required
• Reviewing product test data
• Comparing panel systems
• Advising on positioning
• Coordinating panels with lighting and services
• Predicting the likely improvement
• Testing the completed room

This reduces the risk of buying attractive acoustic products that make little practical difference.

Talk to auricl about acoustic panels and room acoustics

If a room feels echoey, noisy or difficult to communicate in, tell us how the space is used and what is going wrong.

We can assess the room, explain how much acoustic treatment is likely to be needed and help you compare suitable panel systems.