It is the most common conversation our team has, and it almost always starts the same way. Someone has installed acoustic panels in a boardroom, a clinic, or a studio. The room sounds better — noticeably better. But they can still hear the conversation happening on the other side of the wall, and they want to know what went wrong.
Nothing went wrong. The panels are doing exactly what they were designed to do. The problem is that “acoustics” describes two completely separate physical problems, and the products that solve one are not the products that solve the other. Understanding that distinction before you specify will save you budget, disappointment, and the awkward conversation that follows a well-intentioned install.
Two problems that sound the same
Every acoustic complaint falls into one of two categories.
The first is reverberation. Sound generated inside a room bounces off hard surfaces — glass, drywall, polished concrete, laminate — and keeps bouncing for a fraction of a second after the original sound has stopped. Those reflections pile on top of each other and on top of whatever is being said next. The result is a room that feels loud, chaotic, and tiring, where speech is hard to follow even though everyone is nearby. This is the problem in open offices, restaurants, gymnasiums, atriums, and classrooms.
The second is transmission. Sound generated in one room travels through the building structure — walls, floors, ceiling plenums, doorways, ductwork — and arrives somewhere it isn’t wanted. This is the problem in medical exam rooms, HR offices, hotel corridors, and any wall shared between a quiet space and a noisy one.
They feel like the same complaint. “It’s too loud in here” describes both. But absorption solves the first and does almost nothing for the second.
What absorption actually does
An absorptive material is porous. When a sound wave enters it, the wave’s energy is converted into a tiny amount of heat through friction as air moves through the fibre structure. That energy is removed from the room rather than reflected back into it.
This is what our felt does. The fibres trap and dissipate sound energy, which shortens the reverberation time and leaves you with speech that is clear and controlled rather than smeared across every hard surface in the room.
The rating you’ll see attached to absorptive products is NRC — Noise Reduction Coefficient. It’s an averaged figure between 0 and 1 describing how much sound energy a material absorbs across the frequency range most relevant to speech. An NRC of 0.85 means roughly 85% of the sound energy striking that surface is absorbed rather than reflected.
Higher is generally better, but not always. A recording studio treated to near-total absorption sounds lifeless. A performance space needs some reflection to carry sound to the back row. The goal is an appropriate reverberation time for the room’s purpose, not the lowest possible one.
What blocking actually does
Stopping sound from passing between spaces is a different discipline entirely, and it relies on mass, separation, and airtightness rather than porosity. Broadly, it requires some combination of:
- Sound insulation within the wall cavity
- Decoupling — resilient channels or staggered studs that break the vibration path through the structure
- Additional mass, typically extra layers of drywall
- A complete seal around doors, outlets, and any penetration through the assembly
- A barrier above the ceiling, where the plenum is often a wide-open path between rooms
The rating here is STC — Sound Transmission Class, which describes how much sound a wall or floor assembly stops. A standard interior partition might reach STC 35, which is enough that you can’t make out words but not enough to hide raised voices. Genuine speech privacy generally starts around STC 50.
Here is the part that catches people out: airtightness dominates everything else. An otherwise excellent assembly with an unsealed gap around a door or a shared plenum above the ceiling will underperform badly. Sound behaves a great deal like water. It finds the gap.
The comparison in one place
- Symptom: the room echoes, feels loud, speech is hard to follow. That’s reverberation. Fix it with absorption — wall panels, ceiling baffles, clouds, fins. Measured in NRC.
- Symptom: you can hear the room next door, or the floor above. That’s transmission. Fix it with insulation, mass, decoupling, and sealing. Measured in STC. Panels will not help.
How much absorption do you actually need?
There’s no single answer, because it depends on the room’s volume, its surfaces, and what it’s used for. But a few working principles hold up across most projects.
Treat the first reflection points. Sound arriving at a listener after one bounce does the most damage to intelligibility. Ceilings and the upper portion of walls generally earn their keep before anything else.
Don’t neglect the ceiling. It’s usually the largest uninterrupted surface in the room and it’s rarely competing with furniture, art, or millwork. It is the most efficient real estate you have.
Spread it out. Distributed coverage across several surfaces outperforms the same square footage concentrated in one place, and it prevents flutter echo between parallel hard walls.
Air gaps help. Mounting a panel with a cavity behind it improves low-frequency performance without adding material, which is one reason three-dimensional and suspended treatments punch above their weight.
As a rough starting point, many typical commercial rooms respond well to treating somewhere between 15% and 30% of total surface area. Anything with unusual geometry, a hard floor, or a specific performance target deserves a proper calculation rather than a rule of thumb.
When we tell people not to buy from us
If your problem is that the tenant upstairs walks in heels at 6am, or that patients in the waiting room can hear the consultation happening behind the wall, acoustic panels are not your solution. We would rather tell you that at the specification stage than have you install a beautiful treatment that doesn’t address the complaint.
Plenty of projects need both. A therapy room might need an insulated, sealed partition for confidentiality and absorptive surfaces inside so the room itself feels calm. Those are two line items, not one, and they should be budgeted as such from the beginning.
Getting the specification right
The most useful thing you can do early in a project is name the problem precisely. Not “it’s too loud” but “speech from the corridor is intelligible inside the exam room” or “the café has a two-second reverberation time and staff are shouting by noon.” Those two sentences lead to completely different scopes of work.
Our team is happy to work through this with you before anything is drawn or ordered — including telling you when the answer is a wall assembly rather than a product from our catalogue.
Talk to our team about your project, browse the Resources Hub for technical documentation and test data, or read more in our FAQs.