Acoustic and material performance

Table of contents

#Acoustic performance is not a material claim

Acoustic comfort is rarely solved by choosing an "acoustic material". It is solved by specifying the right assembly, at the right location, for the right frequency problem.

A material can look convincing on paper yet underperform in a real interior, once spatial layout, ceiling constraints and frequency behavior are factored in.

#Absorption vs insulation

One of the most common specification errors is confusing absorption and insulation.

Absorption

Absorption reduces reverberation within a room and improves clarity, comfort and speech intelligibility. This is what most interior acoustic panels target.

Insulation

Insulation reduces sound transmission between spaces. It depends on mass, airtightness and construction details. Soft surface materials rarely solve insulation problems on their own.

#What NRC and indices can and cannot tell

NRC and absorption coefficients are useful, but they do not guarantee comfort. They do not describe geometry, layout, directivity, or the low-frequency buildup that dominates many open-plan environments.

A pragmatic reading of ratings

• Use ratings to compare options, not to predict a final experience.
• Ask about the test configuration: thickness, backing, air gap, mounting method.
• Check the problem to solve: echo, speech privacy, overall noise level or transmission.

#The frequency problem

Many interiors fail acoustically because the solution targets the wrong frequency range. Mid and high frequencies are easier to absorb. Low frequencies are much harder and often more disruptive in open spaces.

This is why a robust strategy balances surface absorption, spatial zoning and practical constraints such as ceiling services and architectural intent.

#The effect of assemblies

Acoustic behavior varies significantly with assembly details. Two visually similar products can behave very differently once installed.

What most often changes performance

• Thickness and density
• Backing material type and rigidity
• Air gap behind panels
• Edge conditions and joints
• Mounting method and contact points

#Real-world constraints in offices

In work environments, acoustic discomfort almost never comes from a single source. It typically results from a mix of conversations, collaborative zones, hard surfaces, glazing and HVAC background noise.

Common constraints that shape what is possible

• Open plans and mobile teams
• Building services and lighting limiting ceiling absorption
• Glazing and hard finishes increasing reflections
• Brand-related design constraints reducing available surfaces
• Maintenance requirements in occupied buildings

#Biophilic materials and stabilized moss

Preserved biophilic materials can contribute to an acoustic strategy when integrated into a coherent assembly.

In practice, the best results come when biophilic systems are placed where people spend time and integrated into a space-wide acoustic approach.

#Cork and natural materials

Cork is often chosen for natural material strategies and its tactile qualities. Its acoustic performance depends on thickness, density and mounting — not on the material name alone.

In other words, "cork" is not a performance guarantee. The assembly is the performance.

#Measured results

In complex projects, relying solely on product datasheets is rarely sufficient. This is why Greenmood can collaborate with acousticians to establish baseline conditions and validate results.

What this enables

• Data-driven decisions when acoustic comfort is critical
• Clear documentation for project teams and stakeholders
• Realistic expectations aligned with site constraints

#Documented acoustic performance (laboratory data)

To go beyond material narratives, acoustic performance must rely on measured data.

The values below come from laboratory measurements in reverberant rooms, according to recognized international standards (ISO 354 / ISO 11654 and ASTM C423).

These results provide a comparative basis for understanding the behavior of different biophilic and acoustic materials under controlled conditions, with standardized mounting configurations.

They are intended to support early-stage decisions, specification discussions and documentation, without replacing a project-specific acoustic study.

Measured data guides decisions. Assemblies and positioning determine outcomes.

The indicators shown (αw, NRC, SAA and absorption class) describe a material's effectiveness at absorbing sound energy under standardized test conditions.

They are useful for

• comparing materials on a consistent basis
• identifying absorption ranges suited to mid and high frequencies
• documenting acoustic intent in specification documents

However, these values should not be interpreted as guarantees of in-situ performance.

Important note on real-world performance

Laboratory absorption coefficients represent idealized conditions. In practice, acoustic performance is influenced by many factors, including:

• mounting configuration and backing
• presence or absence of an air gap
• surface continuity and junctions
• room volume, geometry and finishes
• distribution of absorptive surfaces in the space

As a result, identical materials can behave very differently once installed.

This is why acoustic outcomes should be assessed at assembly and system level, not as isolated material properties.

In professional interiors, the most reliable outcomes combine documented data with

• clear assembly definitions
• relevant positioning in the space
• validation by calculation or measurement when needed

At Greenmood, acoustic data is used as a decision-support tool, not a marketing argument. Depending on complexity, this may include simulation, on-site measurement, or both.

#What project teams should ask for

If a supplier cannot explain what was tested, how it was installed, and what the assembly includes, the specification is fragile by default.

#The Greenmood approach

Greenmood designs acoustic and biophilic solutions as systems suited to professional environments. The priority is to reduce ambiguity during specification and favor stable, predictable outcomes in occupied buildings.

Our priorities

• Assembly clarity and specification support
• Documented performance when relevant
• Durability and maintainability in real conditions
• Possible collaboration with acousticians on complex scopes

Specification and performance guide

To help teams move from design intent to reliable implementation, we have prepared a reference document dedicated to the specification and performance of biophilic acoustic assemblies in professional fit-outs.

The guide consolidates assembly logic, acoustic considerations, documentation expectations and validation principles generally required during specification and project review phases.

Download the specification and performance guide

#Resources

For further reading, these resources help clarify the difference between material narratives and actual acoustic performance.

References

• Amorim: materials vs performance
• Ekko: acoustic materials and the language of calm design
• Impact Acoustic: overview of acoustic performance
• EMPA: acoustic performance of materials
• MDPI: acoustic materials research overview

Conclusion