For windows
Soundproof curtains for windows in Nepal
What we make for a window is a curtain, not a window. It is a layered barrier that hangs over the opening and covers it, with a mass loaded vinyl core doing the blocking and an absorptive face on each side. We do not manufacture or supply glazing, window units, frames or secondary glazing, so if the answer to your problem is a new window, this is not that product. Manufactured in Palwal, India and supplied to Nepal with strong logistics.
- Barrier core
- SoundBlanket® MLV, STC 30
- Curtain
- 10 to 12 mm, 4500 GSM, Class B
- Sizes
- 8 x 4 ft, 5 x 4 ft or made to size
- Quote
- Within 48 hours, from your measurements
Send the width and height of the opening including the frame, the mounting point you have available, and what the noise is. We manufacture and supply the curtain and the hanging hardware; we do not carry out on site consultancy, measurement or installation.
Quick answer for Nepal: Made-to-measure soundproof curtains that cut window noise by up to 30 dB. Removable and reusable, with a measuring guide and mounting hardware included. MMT Acoustix manufactures these products in Palwal, India and supplies Nepal, with a quote within 48 hours.
01 / What actually goes wrong
Why a closed window still sounds open
A window is the lightest part of the wall and the only part with moving joints in it. Both of those matter more than the glass thickness people usually worry about.
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Glass is one thin leaf
A single pane is a light single panel, so it passes traffic, horns and construction noise far more freely than the masonry around it. Adding a curtain does not turn it into a heavy wall, but hanging a dense, sealed layer in front of the opening gives the sound a second thing to get through, which is the only thing you can do to a window without replacing it.
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The gaps behave like open holes
Sliding tracks, beading, a shutter box and a frame that has moved with the building all leave narrow slots, and a slot passes sound out of all proportion to its size. This is why two identical windows in the same flat can sound completely different. Perimeter silicone and EPDM seals on the opening leaves are worth doing before anything is hung in front of them.
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The glass reflects back into the room
Separate from anything coming in. A large glazed wall is a hard parallel surface, so calls get harder to hear and a room with a lot of glass sounds bright and tiring. That is an absorption problem inside the room, and it is what acoustic curtains at NRC up to 0.70 are for, rather than the barrier curtain on this page.
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Before: the opening left as it is
Street noise arrives through the glass, through the track gaps and around the frame at the same time. Adding a heavier pane deals with the first of those and none of the other two, which is why glazing upgrades sometimes disappoint.
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After: the opening covered and closed at the edges
The curtain covers past the frame on all four sides and is held tight at the perimeter with velcro, so the barrier is continuous rather than a sheet hanging loose in front of a hole. Coverage and edge closure decide the result far more than the fabric does.
02 / The build-up
What is inside the curtain, outside in
This is not a heavy blackout curtain. A blackout curtain is one dense fabric; this is a barrier with an absorber on both faces of it, which is why the finished panel is 10 to 12 mm thick and 4500 GSM rather than a few hundred GSM.
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Layer 1: the velvet face
350 GSM velvet on both sides. It is the visible layer and it takes the first of the energy out before it reaches the core, so the curtain reads as a furnishing rather than as industrial material. Choose the shade to suit the room; it makes no difference to the build.
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Layer 2: acoustic foam, both sides of the core
High density acoustic foam sits behind the velvet on each face. Its job is absorption, not blocking: it reduces what reflects off the curtain back into the room, and it keeps the curtain from behaving like a single hard sheet.
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Layer 3: the SoundBlanket® MLV core
The centre of the curtain, and the only layer that blocks. Mass loaded vinyl at 2100 kg/m³, limp rather than stiff, so it adds weight without ringing. This is where the curtain's STC 30 comes from and the reason the finished panel weighs about 4.5 kg per square metre.
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Layer 4: hanging and edge closure
Brass hooks carry the weight from a rod, a track or a ceiling fixing. Double sided velcro holds the perimeter down against the reveal or the wall, which is the part that decides how well the whole thing works. Velcro belts roll the curtain up and hold it when the window is in use, and the system comes off the wall again, so it suits a rented flat.
What the curtain does and does not do
| Problem at the window | What to use | Note |
|---|---|---|
| Traffic and street noise coming in | Soundproof curtain, STC 30, 10 to 12 mm, 4500 GSM | Needs full coverage past the frame and a closed perimeter |
| Gaps in a sliding or casement frame | Silicone and EPDM window seals, 6 x 6 mm D-type | Do this first. A slot passes more than the glass does |
| Bright, reflective room with a lot of glass | Acoustic curtains, NRC up to 0.70, 5 mm, 500 GSM | Absorption inside the room, a different product and a different job |
| Wall around the window still passing sound | SoundBlanket® in the wall build-up, STC 34 at 4 mm | A curtain cannot fix a wall. See walls |
| A window that has to be openable and quiet | Not a curtain | That is a glazing question. We do not supply glazing or window units |
STC 30 is the figure for the curtain as a product. It is not a rating for your window opening, which depends on the wall, the frame, the gaps and how much of the reveal the curtain covers. A figure for a real opening is the scope of an acoustic consultant.
03 / How to measure your window
Two measurements, plus how much you want to overlap
Take them with a tape and write them down in millimetres or inches, either is fine. Coverage beyond the opening is not optional; a curtain cut to the size of the glass leaks round all four edges.
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Measuring, in order
Measure the opening including the frame, not the glass. Then decide where the curtain will hang from, because the height is measured from that point and not from the top of the window.
- Width. Across the full opening including the frame, then add overlap on both sides so the curtain lands on solid wall or on the reveal
- Height. From the rod, track or ceiling fixing down to where the curtain should finish, with extra above the frame so the head is covered too
- Mounting point. Wall or ceiling mounted closes tighter than an inside-the-reveal fixing, so say which you can use
- Obstructions. Note an AC unit, a shutter box, a grille or a handle that the curtain has to clear
- Frame material. Metal, timber or uPVC, so we can advise on the velcro and the seals
Sizes, weight and care
| Item | As supplied |
|---|---|
| Standard sizes | 8 x 4 ft and 5 x 4 ft, and made to your measurements |
| Thickness | 10 to 12 mm finished |
| Weight | About 4.5 kg per square metre, so the fixing has to be into something solid |
| Hanging | Brass hooks, plus double sided velcro for the perimeter and belts to roll it up |
| Fire | Class B |
| Cleaning | Wipe with a damp cloth. Removable and reusable, so it can move with you |
| Suits | Metal and wooden windows and doors, and openings with no leaf at all |
- OVERLAP
Cover past the frame on all four sides. The edges are where a curtain leaks, not the middle.
- SEAL FIRST
Close obvious track and frame gaps with window seals before hanging anything. It costs little and it changes more than extra fabric would.
- FIXING
Fix the rod or track to the wall or slab rather than to the window frame, so the perimeter can be pulled tight against solid material.
04 / What we see go wrong
Five ways a window curtain disappoints
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Ordered to the size of the glass
The curtain finishes where the window finishes, so there is an open edge on every side. Coverage past the frame is the difference between a barrier and a hanging sheet.
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Hung loose, with no perimeter closure
Without the velcro holding the edges down, air and sound move freely around the panel. The mass in the core cannot do anything about a path that goes round it.
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Expecting a curtain to fix a wall
If the noise is also coming through the wall, the floor or a shared duct, covering the window moves the complaint rather than ending it. Check where the sound is actually arriving first.
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Buying a blackout curtain and expecting this
A heavy decorative curtain has no barrier core. It changes the light and a little of the room's reverberation, and it does not block.
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Fixing into the window frame
A light aluminium or uPVC frame is not a good anchor for about 4.5 kg per square metre, and fixing there leaves the curtain inside the reveal where it cannot seal against the wall.
05 / Specifications
Tested performance, with the standard it was measured to
| Product | Tested performance | Test standard |
|---|---|---|
| SoundBlanket mass loaded vinyl | STC 30 at 2.5 mm, STC 34 at 4 mm; 2100 kg/m³ | ASTM E90 |
| MMT Acoustix acoustic foam | NRC 0.90 at 50 mm (Pyramid); 0.95 at 50 mm (Galaxy) | ASTM C423 |
| Soundproof curtains | STC 30, NRC 0.20, 4500 GSM; up to 30 dB reduction | ASTM E90 / C423 |
Test reports are issued with project supply. NRC and STC are the figures we publish and stand behind; anything beyond those two is the scope of an acoustic consultant. The full set of reports is listed on the certifications page.
06 / How we can help
What we do, and what we do not
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We do
- Manufacture the curtain, the SoundBlanket® core and the seal range at the Palwal plant, Haryana
- Make curtains to your window measurements, with the hanging hardware supplied
- Quote from your width, height and mounting point, usually within 48 hours
- Supply test reports, technical data sheets and specification text
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We do not
- Supply glazing, window units, frames or secondary glazing of any kind
- Carry out on site acoustic consultancy or measurement, or rate a finished opening
- Install. The curtain is supplied with its hardware for you or your fitter to hang
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We refer
We work with associated acoustic consultants and installers across India and can put you in touch with them for design verification or execution. Ask when you send your measurements.
Questions