Soundproof curtain vs. acoustic curtain: what's the difference and which one to choose?
A soundproofing curtain blocks noise coming from outside (street, neighbours, traffic) by creating a dense, multilayer barrier in front of your windows. An acoustic curtain absorbs echo and reverberation inside a room to improve sound comfort. Soundproofing insulates, acoustics corrects. For a noisy apartment facing the street, choose a soundproofing curtain. For a room that echoes (open-plan office, tiled living room), choose an acoustic curtain.
These two terms are commonly used interchangeably, leading to confusion when purchasing. Choosing the wrong type of curtain can result in complete ineffectiveness against your noise problem. This guide compares the two solutions with technical data, a summary table, and a decision tree to help you invest in the right solution.
What is a soundproofing curtain?
A soundproofing curtain is a multilayer textile barrier designed to prevent external noise from entering a room. Its objective is pure sound insulation: to create a shield against sound waves passing through your windows or front door. The best models achieve 18 to 25 dB of attenuation, which is a reduction comparable to a closed interior door (18-27 dB).
The principle is based on the mass law in acoustics: the heavier and denser a material, the less it vibrates under the impact of sound waves. To achieve this result, soundproofing curtains use multi-layer assemblies: high-density cotton fleece, polymer or metallic membranes, and technical linings. The total density generally exceeds 500 g/m², with the most effective models reaching 620 g/m² and more.
Concrete use case: you live on the first floor of a busy street, and traffic noise reaches 70 dB with the window closed. A high-performance soundproofing curtain (22 dB attenuation*) brings this level down to 48 dB, below the threshold of normal conversation. It is particularly effective on frequencies from 500 to 2,000 Hz (voices, engines, horns), which represent the majority of urban noise.
What is an acoustic curtain?
The acoustic curtain corrects the internal sound environment of a room; it does not insulate it from external noise. Its mission is to absorb sound waves that bounce off hard surfaces (bare walls, tiles, bay windows) to eliminate echo and reduce reverberation time. A quality acoustic curtain can reduce reverberation time by 30 to 60%, with an absorption coefficient (NRC) of 0.5 to 0.9 depending on the material and thickness.
It is crucial to understand what it does not do: an acoustic curtain does not block street noise in any way. It only treats sounds already present inside the room. Physically, it uses porous materials (thick cotton velvet, wool felt). The microscopic structure of these fabrics traps sound waves and converts acoustic energy into heat through friction.
Concrete use case: a 30 m² meeting room surrounded by glass walls where voices echo to the point of making video conferences inaudible. The reverberation time exceeds 1.5 seconds (the NF S31-080 standard recommends less than 0.8 seconds for offices). Heavily pleated acoustic curtains, combined with wall panels, bring the reverberation below this threshold. This is also a standard in recording studios and open-plan offices.
Comparison table: soundproofing vs. acoustic
| Feature | Soundproofing curtain (insulation) | Acoustic curtain (correction) |
|---|---|---|
| Main use | Block external noise | Reduce internal echo and reverberation |
| Physical principle | Mass law and multi-layers (barrier effect) | Porosity and wave absorption (sponge effect) |
| Performance | 18 to 25 dB attenuation | NRC 0.5 to 0.9 (30 to 60% reverberation reduction) |
| Typical density | 500 to 620+ g/m² | 200 to 400 g/m² |
| Composition | Multi-layers (fleece, blocking membrane) | Simple or double porous fabric (velvet, wool, felt) |
| Recommended installation | As close to the window as possible, overhang 15-20 cm minimum | Heavily pleated (1.5 to 2 times fullness) to capture sound |
| Noise treated | External airborne (street, traffic, neighbourhood) | Internal reverberation (echo, resonance) |
| Indicative price | 100 to 400 euros | 50 to 200 euros |
Key point: sound insulation requires superior density and multi-layer technicality (minimum 500 g/m²), justifying a higher investment. Acoustic absorption relies on the surface texture and porosity of the material.
How to choose according to your situation?
To determine which solution is right for you, analyze the source of your sound discomfort. The decision revolves around a simple logical tree: is the noise source external, internal, or both?
The noise comes from outside: opt for a soundproofing curtain.
Example: a first-floor apartment on a busy boulevard, double-glazed windows letting in scooter noise and loud voices at 60 dB. Simple velvet won't be enough. A multi-layer barrier is needed to prevent waves from passing through. Windows are responsible for about 40% of a dwelling's sound loss. For these cases, our made-to-measure blackout, thermal, and soundproofing curtain combines sound insulation (22 dB*), thermal insulation (7 °C*), and blackout (100%*).
The problem is internal echo: opt for an acoustic curtain.
Example: an 80 m² architect's office in an open-plan setting, polished concrete floor. The space echoes, conversations blend together, and auditory fatigue sets in. The nuisance is produced internally. Large, heavily pleated acoustic curtains (1.5 to 2 times the width of the window) absorb vocal frequencies (500-2,000 Hz) and reduce reverberation by 30 to 60%.
You suffer from both: opt for a combined curtain.
Common situation: a living room with a home cinema facing a busy street. It's necessary to both block outside noise and improve internal acoustics. A high-density multi-layer curtain meets both needs: the mass blocks outside noise, and the porous textile face on the room side absorbs reverberation.
Can soundproofing and acoustic be combined in a single curtain?
Yes. A well-designed multi-layer curtain superimposes materials with complementary functions: a porous decorative face (thick cotton velvet) to absorb internal echo, combined with dense internal membranes to block external noise. The porous face fulfills the acoustic role, and the dense layers fulfill the soundproofing role.
Kurtens' made-to-measure soundproofing curtains combine both functions. Each curtain is made to order to the exact dimensions of your opening, with a density of 620 g/m² which combines three performances:
- 22 dB measured sound attenuation*
- 100% certified blackout*
- Up to 7 °C thermal gain*
Made-to-measure is crucial for actual sound performance: a standard curtain inevitably allows sound leaks on the sides and bottom. A curtain made to the exact dimensions of the window gains 3 to 5 dB compared to a standard size, thanks to the elimination of lateral leaks. Configurable online to the nearest centimetre, delivered in 2 to 3 weeks.
*Data from tests conducted under optimal conditions.
Frequently Asked Questions
What is the difference between a soundproofing curtain and an acoustic curtain?
A soundproofing curtain blocks noise coming from outside (street, traffic, neighbours) thanks to its mass and multi-layer construction. An acoustic curtain absorbs echo and reverberation inside a room thanks to its porous texture. Soundproofing insulates (prevents noise from entering), acoustics corrects (treats noise already present). These are two different functions that address different problems.
Does an acoustic curtain block street noise?
No. An acoustic curtain reduces echo and reverberation inside a room, but it does not block external noise. To block street noise, you need a high-density multi-layer soundproofing curtain (minimum 500 g/m²). An acoustic curtain made of velvet or felt (200-400 g/m²) improves indoor sound comfort but does not prevent noise from entering through the window.
Which curtain should I choose for a noisy apartment?
If the noise comes from the street (traffic, horns, construction): a high-density multi-layer soundproofing curtain installed in front of the windows. The best models attenuate 18 to 25 dB. If the noise is internal (echo in a large living room, reverberation in an office): an acoustic curtain made of velvet or felt, heavily pleated. If you suffer from both: a high-density combined curtain that blocks external noise and absorbs internal reverberation.
How many decibels does a soundproofing curtain reduce?
Soundproofing curtains on the market offer performances of 5 to 25 dB depending on the category. Basic thick curtains (150-300 g/m²): 5-7 dB, barely perceptible. Mid-range models (350-500 g/m²): 12-18 dB. High-performance custom-made curtains (500+ g/m²): 18-25 dB. Kurtens curtains achieve 22 dB measured attenuation* with 620 g/m². For reference, a standard interior door offers 18-27 dB.
Is a soundproofing curtain also acoustic?
A high-density soundproofing curtain naturally has a partial acoustic effect: its mass absorbs part of the internal reverberation in addition to blocking external noise. The reverse is not true: a lightweight acoustic curtain does not have the mass necessary to block noise. Kurtens curtains (620 g/m², multi-layer) combine both functions: sound insulation (22 dB*) and absorption of reverberation on the room side.
Does a soundproofing curtain work on a front door?
Yes. The front door is often the second point of sound leakage after windows, especially in old apartments. A soundproofing curtain installed in front of the door creates an additional barrier against hallway, landing, and street noise. The curtain should extend 15 to 20 cm beyond each side of the frame and reach the floor for maximum effectiveness. A made-to-measure curtain ensures this full coverage.
What NRC coefficient for an effective acoustic curtain?
The NRC (Noise Reduction Coefficient) measures a material's absorption capacity on a scale of 0 to 1. For an effective acoustic curtain, aim for an NRC of 0.5 minimum (absorbs 50% of sound waves). The best acoustic curtains made of wool felt or thick velvet achieve an NRC of 0.7 to 0.9. For comparison, a smooth concrete wall has an NRC of 0.02 (almost no absorption) and thick carpet has an NRC of 0.3 to 0.5.
Can a soundproofing curtain be used in a recording studio?
A soundproofing curtain blocks external noise (useful if the studio is in a noisy environment) but is not sufficient for internal acoustic treatment. A recording studio requires both: sound insulation to prevent external noise from contaminating the recording, and acoustic treatment to control reverberation and achieve a clean sound. A high-density multi-layer curtain contributes to both, but must be supplemented by dedicated acoustic panels on the walls and ceiling.
Other curtain tips
Discover our latest articles
