NRC Values of Leading Brands in Direct Comparison

What the NRC value really tells you and where its limits lie

The Noise Reduction Coefficient is an average of four frequencies: 250 Hz, 500 Hz, 1000 Hz and 2000 Hz. An NRC of 0.85 means that on average 85% of the sound energy in these bands is absorbed. That sounds simple, but it obscures two critical points.

First: low and high frequencies are completely absent. A panel may only achieve 0.15 at 125 Hz and already 0.95 at 4000 Hz – yet the NRC would still sit at a solid 0.80. For a home studio with bass problems that would be fatal, but for a speech-heavy meeting room it would be perfectly adequate. I therefore always recommend looking at the complete absorption curves, not just the summarised NRC.

Second: mounting distance influences the NRC massively. Most manufacturers give values for Type A (glued directly to the wall) and Type E (with spacing, usually 10 cm). In a project in Munich, the NRC of a 40-mm polyester panel rose from 0.65 (Type A) to 0.95 (Type E) – a difference of 46%. Anyone who mounts panels without spacing often throws away a third of the possible performance.

Third: the tolerance in laboratory measurements is ±0.05. A stated NRC of 0.90 can realistically lie between 0.85 and 0.95. With no-name suppliers without an accredited test certificate, I would factor in a further 10% deduction.

Manufacturer ranking by NRC for direct wall mounting (Type A)

In this overview you can see the NRC values you can expect with flush wall mounting. All figures refer to the standard thickness of 40 mm, where available.

| Manufacturer / Range | NRC (Type A) | Thickness | Price per m² | Material | Notes | |----------------------|-------------|-------|--------------|----------|-------------| | EQ Acoustics Classic | 0.85 | 50 mm | £62 | PU foam | Very soft surface, fragile | | Addictive Sound Circa | 0.75 | 40 mm | £78 | Polyester | Solid, washable, somewhat stiff | | Akustikpur Studio | 0.70 | 40 mm | £55 | Polyester | Good value for money | | Vicoustic Flat Panel | 0.65 | 40 mm | £89 | Polyester + wool blend | High-quality appearance, medium NRC | | Artnovion Petra | 0.60 | 40 mm | £125 | Polyester + stone wool | Design focus, heavy | | Basotect Noppenschaum | 0.55 | 50 mm | £18 | Melamine foam | Cheap, but fire hazard without B1 certificate | | Felt Right Acoustic Tiles | 0.50 | 12 mm | £48 | PET felt | Thin, high-frequency only, modular | | Muuto Fiber Tiles | 0.40 | 12 mm | £95 | Wood fibre | Pure decoration, acoustically weak |

The table shows: there are worlds between design panels and functional absorbers. An EQ Acoustics Classic absorbs more than twice as much as a Felt Right Tile for the same area. In a project in Hamburg, the client had mounted 12 m² of Muuto tiles and wondered why the reverberation hardly dropped – the NRC of 0.40 simply isn't enough for a 35-m² room.

In price terms the correlation is loose: Vicoustic sits at £89 per m² and NRC 0.65, Akustikpur at £55 and NRC 0.70. Here you're paying for design, brand and European manufacture, not primarily for absorption performance.

NRC values with spaced mounting (Type E, 10 cm air gap)

This is where it gets interesting. An air gap between panel and wall reduces sound velocity in the cavity, allowing deeper frequencies to be absorbed as well. The NRC rises – sometimes dramatically.

**Addictive Sound Circa (40 mm):** Type A: 0.75 → Type E: 0.95 (+27%)

**Akustikpur Studio (40 mm):** Type A: 0.70 → Type E: 0.90 (+29%)

**Vicoustic Flat Panel (40 mm):** Type A: 0.65 → Type E: 0.88 (+35%)

**Basotect Noppenschaum (50 mm):** Type A: 0.55 → Type E: 0.80 (+45%)

**Felt Right Acoustic Tiles (12 mm):** Type A: 0.50 → Type E: 0.55 (+10%)

Notable: thin PET felt panels benefit little from spacing because the material itself has insufficient flow resistance. Thick polyester and foam panels gain massively, on the other hand. In a surgery in Cologne we mounted Akustikpur panels flush at first (NRC 0.70) – the client was disappointed. After conversion to spacers (5 cm) the absorption performance rose noticeably, and speech intelligibility improved by an estimated 30%.

My tip: if structurally possible, always work with at least 5 cm spacing. That costs you only a few pounds for spacers, but brings an NRC gain of 0.10 to 0.20 – equivalent to 20 to 30% more absorbed area.

Frequency response in detail: where each brand has its strengths

The NRC is an average, but the music happens at individual frequencies. Here you can see three brands as examples with the same NRC of 0.75, but completely different behaviour:

**EQ Acoustics Classic (Type A):** 125 Hz: 0.20 | 250 Hz: 0.70 | 500 Hz: 0.85 | 1000 Hz: 0.90 | 2000 Hz: 0.95 | 4000 Hz: 1.00

Typical high-frequency profile. Excellent for speech, unsuitable for bass-reflex loudspeakers. In a living room in Stuttgart this led to muffled sound because bass came through but highs were over-damped.

**Addictive Sound Circa (Type E, 10 cm spacing):** 125 Hz: 0.45 | 250 Hz: 0.80 | 500 Hz: 0.95 | 1000 Hz: 1.00 | 2000 Hz: 1.00 | 4000 Hz: 0.95

Significantly more balanced. Already 0.45 at 125 Hz – that's notable for 40 mm thickness. Ideal for hi-fi rooms and home offices with video conferences.

**Vicoustic Flat Panel (Type A):** 125 Hz: 0.15 | 250 Hz: 0.55 | 500 Hz: 0.70 | 1000 Hz: 0.75 | 2000 Hz: 0.85 | 4000 Hz: 0.90

Slow rise. Only really effective from 1000 Hz. In a meeting room in Zurich that was just adequate, but in a recording studio it would be too weak for bass.

**Practical conclusions:** - Speech and office: NRC from 0.65 with emphasis 500–2000 Hz is sufficient. - Hi-fi and home cinema: NRC from 0.80 and absorption at 125 Hz at least 0.30. - Recording studio: NRC from 0.90 and bass traps in addition.

Value analysis: where you get the most absorption for your money

I calculate here with "absorbed m² per £100 investment". Assumption: 10 m² of room area should be absorbed.

**Basotect Noppenschaum (Type E):** Cost: 10 m² × £18 = £180 NRC: 0.80 Effective absorption: 10 × 0.80 = 8.0 m² Absorption per £100: 4.44 m²

**Akustikpur Studio (Type E):** Cost: 10 m² × £55 = £550 NRC: 0.90 Effective absorption: 9.0 m² Absorption per £100: 1.64 m²

**Addictive Sound Circa (Type E):** Cost: 10 m² × £78 = £780 NRC: 0.95 Effective absorption: 9.5 m² Absorption per £100: 1.22 m²

**Vicoustic Flat Panel (Type E):** Cost: 10 m² × £89 = £890 NRC: 0.88 Effective absorption: 8.8 m² Absorption per £100: 0.99 m²

**Artnovion Petra (Type E):** Cost: 10 m² × £125 = £1250 NRC: 0.80 Effective absorption: 8.0 m² Absorption per £100: 0.64 m²

Basotect is unbeatable on pure numbers – but: without B1 classification the material is a fire hazard, the appearance is questionable and durability low. In a doctor's surgery in Berlin, Basotect became porous after 18 months and crumbled. I recommend Basotect only for temporary solutions or trial installations.

Akustikpur offers the best balance: solid NRC, moderate cost, European manufacture, good feel. In over 60 of my projects this was the standard recommendation.

Vicoustic and Artnovion are design products. Anyone who prioritises appearance and has the budget is in the right place here – but purely acoustically there are cheaper routes to more absorption.

Mounting methods and their influence on measured NRC

Many manufacturers give only one NRC without specifying whether Type A, D or E is meant. That leads to confusion. Here is the system according to ISO 354:

- **Type A:** Panel glued directly to wall or ceiling, no air layer. - **Type D:** Panel with 2–3 cm spacing, e.g. using timber battens. - **Type E:** Panel with 10 cm spacing, e.g. suspended ceiling sails.

In my experience the differences lie at:

- Type A → Type D: +10 to +15% NRC - Type A → Type E: +25 to +35% NRC

An example from a home office in Frankfurt: - Addictive Sound Circa, 8 m², Type A: NRC 0.75 → effectively 6.0 m² absorbed. - Same panels, Type E: NRC 0.95 → effectively 7.6 m² absorbed.

By using Type E mounting the client saved the equivalent of 2 m² of panels (around £156) and still had greater effect.

**Practical mounting tips:**

- For wall mounting: spacers of rigid foam wedges, 5 cm thick, every 40 cm. Cost: around £3 per m². - For ceiling mounting: steel cable system with adjustable grips. Cost: around £12 per m². - In rental flats: self-adhesive hook-and-loop tape and panels glued to lightweight MDF backing boards. That keeps the wall intact.

Important: with spaced mounting the first resonance frequency drops, but bass is also better absorbed. That is almost always a gain.

Special cases: hybrid panels and diffuser-absorber combinations

Some manufacturers offer panels that absorb AND diffuse. The NRC value here is only conditionally meaningful, because diffusion does not flow into the NRC.

**Vicoustic Multifuser DC2:** NRC: 0.30 (Type A) Absorption at 500–2000 Hz: 0.40 Diffusion: 500–4000 Hz

Purely by NRC that sounds weak. But in a music room in Vienna, combined with 6 m² of full absorbers (NRC 0.90), this gave significantly more natural room acoustics than 10 m² of full absorbers alone. The room sounded "livelier" without being reverberant.

**Artnovion Azteka:** NRC: 0.45 (Type A) Focus: diffusion 1000–4000 Hz, moderate absorption 250–1000 Hz

Interesting for hi-fi listeners who want to reduce reverberation without deadening the room. I usually deploy such hybrid products as a supplement, not as the main absorber.

**Conclusion on hybrids:** If the room is already over-damped (RT60 below 0.3 s), diffuser-absorbers can help. For normal living and office spaces, however, I would first focus on pure absorbers.

For which room which NRC range makes sense

Here is a practical guide, based on RT60 targets and room size:

**Home office, 15–20 m²:** Target RT60: 0.4–0.5 s Recommended panel area: 4–6 m² NRC: at least 0.70 (Type A) or 0.85 (Type E)

**Living room with hi-fi, 25–35 m²:** Target RT60: 0.5–0.6 s Recommended panel area: 6–10 m² NRC: at least 0.80 (Type E), ideally full-spectrum from 125 Hz

**Meeting room, 30–40 m²:** Target RT60: 0.4–0.5 s Recommended panel area: 8–12 m² NRC: at least 0.75, emphasis 500–2000 Hz

**Doctor's surgery waiting room, 20 m²:** Target RT60: 0.5 s Recommended panel area: 5–7 m² NRC: 0.65–0.80 sufficient, focus on speech frequencies

**Home studio, 20 m²:** Target RT60: 0.3–0.4 s Recommended panel area: 10–14 m² NRC: at least 0.90, plus bass traps for 63–125 Hz

In a project in Düsseldorf a photography studio of 40 m² had mounted 8 m² of panels with NRC 0.60. Effective absorption: 4.8 m². That was too little – the RT60 remained at 0.9 s. After retrofitting to 12 m² with NRC 0.85 (Type E) the RT60 dropped to 0.5 s, and voice recordings became noticeably clearer.

Where lab data diverge from practice: my observations

Theory and reality sometimes gape apart. Three points that don't appear in any datasheet:

**1. Mounting inaccuracies:** If panels don't sit flush, gaps arise. In a Berlin office, mounting adhesive was used that was only applied in spots. The panels bowed slightly, the effective NRC dropped from a stated 0.80 to an estimated 0.65. Solution: glue over the full area or screw with washers.

**2. Soiling:** Polyester panels in smoking areas or kitchens collect grease and dust after 12–18 months. That clogs the pores, the NRC drops. In a catering environment in Munich I measured only 0.55 after two years instead of an original 0.75. Regular vacuuming helps, but not permanently.

**3. Moisture:** Foam panels without impregnation soak up water in damp basement rooms. That does briefly increase mass and thus absorption at low frequencies, but leads to mould and odour. In a rehearsal room in Hamburg we had to dispose of all EQ Acoustics panels after one year.

Checklist: how to choose the right panel for your project

Before you order, clarify these points:

- **Room size and use:** Office, hi-fi, studio? That determines the target RT60. - **Mounting option:** Can you leave spacing (Type E) or only glue (Type A)? - **Budget:** How many pounds per m² is realistic? - **Frequency focus:** Do you have bass problems (125–250 Hz) or only speech reverberation (500–2000 Hz)? - **Appearance:** Does it need to be design-oriented or does only function count? - **Certificates:** Is B1 fire protection mandatory (commercial) or optional (private)?

A typical scenario from my consultancy: Client: Home office, 18 m², budget £400, rental flat (no drill holes), improve speech intelligibility in video conferences. Recommendation: 6 m² Akustikpur Studio (£330), Type A with hook-and-loop tape, NRC 0.70. Plus a rug (2 × 3 m) for the floor. Result: RT60 dropped from 0.8 s to 0.45 s, echoes gone, client satisfied.

My conclusion after over 200 projects

The NRC is a useful reference value, but not a dogma. A panel with NRC 0.70 and matching frequency response can be better than one with NRC 0.90 and high-frequency bias. Always look at the absorption curve – most manufacturers provide it on request.

Brands like Addictive Sound and Akustikpur offer solid performance at fair prices. EQ Acoustics is top for studios, but fragile. Vicoustic and Artnovion shine visually but cost 30–50% more for similar NRC. Basotect is cheap, but only to be recommended for uncritical applications.

If you have the choice: mount with spacing (Type E). That brings 25–35% more absorption performance for minimal extra effort. And don't forget to treat the floor area acoustically – a rug with 0.30 NRC over 6 m² gives you 1.8 m² effective absorption for £150. That is often more efficient than another wall panel.

If you're uncertain, start with 50% of the calculated panel area, measure the RT60 (free apps like "AudioTools" are sufficient), and retrofit if needed. Better to optimise in stages than overshoot the mark and end up with a sterile room.