For walls
Soundproofing and acoustic treatment for walls in Durban
A wall is an assembly, not a material. What it stops depends on its mass, on whether the two faces are decoupled, on what fills the cavity, and on how well it is sealed at the head, the floor and every socket box. Change one of those and you change the result; add a panel to the face and you change how the room sounds, not what passes through it. Manufactured in Palwal, India and supplied to Durban, South Africa with strong logistics.
- Mass layer
- SoundBlanket® MLV, STC 34 at 4 mm
- Cavity layer
- BassBloc®, NRC 0.85 at 20 mm
- Room face
- PET felt, wood or fabric, NRC 0.30 to 0.90
- Quote
- Within 48 hours, from a wall section
Send the existing wall section, the wall area, what is on the other side of it, and whether the wall is still open or already finished. We manufacture and specify; we do not carry out on site consultancy, measurement or installation.
Quick answer for Durban: Wall sound isolation systems and acoustic wall panels that stop noise and vibration passing through partitions, improve speech privacy and control echo. MMT Acoustix manufactures these products in Palwal, India and supplies Durban, South Africa, with a quote within 48 hours.
01 / What actually goes wrong
Three reasons a wall underperforms
They are separate faults with separate fixes. Most walls that disappoint have at least two of them, and the one people spend money on is usually the third.
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A single leaf, whatever it is made of
One board on one set of studs behaves as one panel. Adding more of the same material to the same leaf gives progressively less back for each layer, and every single leaf has a frequency band where it goes transparent and passes sound far better than its weight suggests. That is why a heavy single wall can still let a television through cleanly. A second, separate leaf changes the behaviour; a thicker single leaf only shifts it.
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The sound goes round the wall, not through it
Flanking is the usual reason a well specified wall measures badly on site. The partition stops at the false ceiling and the sound carries on over the top of it. Socket and switch boxes are cut back to back through the same stud bay. A conduit chase, a plumbing riser or a continuous skirting carries energy past the wall entirely. None of this is visible once the wall is closed, which is why it has to be dealt with while the wall is open.
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The room face is hard and parallel
This is the one you hear from inside the room: speech that smears, meetings that are tiring, recordings with a boxy tail. It has nothing to do with what the wall blocks. It is dealt with by absorption on the face, placed where the reflections are rather than spread evenly, and it is the only one of the three problems that a panel on its own solves.
02 / The build-up
Mass, then cavity, then face
Three layers, each doing a job the other two cannot. The order matters because the first two have to go in while the wall is open, and the third is the only one that can be added later.
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Layer 1
SoundBlanket® mass loaded vinyl
The mass. A limp, dense membrane fixed to the studwork or bonded behind the board, so the leaf weighs far more than its thickness suggests. It is what reduces transmission through the wall, and because it works by mass it is only as good as its sealing: laps, edges, socket cut-outs and service penetrations all get closed, or the sheet performs like the hole rather than like the sheet.
STC 30 at 2.5 mm, STC 34 at 4 mm, to ASTM E90. 2100 kg/m³. Class A surface burning to ASTM E84. Custom 1 to 10 mm. Sheets 8 x 4, 16 x 4 and 32 x 4 ft.
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Layer 2
BassBloc® in the cavity
An empty cavity between two leaves is a spring with nothing to damp it, and at the frequency where that spring resonates the wall performs worse than either leaf on its own. Filling the cavity damps it. This is also the layer that does something in the range where a subwoofer, a compressor or a neighbour's television actually lives. It sits inside the build-up and is never left exposed to the room.
NRC 0.85 at 20 mm, 0.95 at 40 mm, to ASTM C423. Effective 100 to 500 Hz. 100 kg/m³. Rolls 1800 x 900 mm.
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Layer 3
The acoustic face
The visible layer, and the one that fixes how the room sounds rather than what leaves it. Choose it on how much absorption the room needs and how the wall has to look; the two are not in conflict, because every finish below has a published NRC. Over a 20 mm BassBloc® backing a PET felt face reaches NRC 0.90, which is how a thin panel gets deep absorption without a deep build-up.
PET felt NRC 0.30 at 9 mm to 0.60 at 24 mm, 0.90 over BassBloc® · Wooden slats NRC 0.75 · Perforated NRC 0.70 · Fluted NRC 0.60 · Galaxy foam NRC 0.95 at 50 mm
Layer order by wall type
| Wall | From the structure inwards | What it is for |
|---|---|---|
| New stud partition | Board, SoundBlanket® 4 mm on the studs, BassBloc® 20 mm filling the cavity, board, then the acoustic face | Mass on both leaves, a damped cavity between them, absorption in the room |
| Existing masonry wall | SoundBlanket® 2.5 to 4 mm bonded to the wall, battens, BassBloc® 20 mm between them, board, then the face | Adds mass and a second leaf without rebuilding |
| Party wall, retrofit lining | Independent battens off the existing wall, BassBloc® 20 mm, SoundBlanket® 4 mm, board, then the face | Keeps the new leaf from being rigidly tied to the old one |
| Wall head and floor junction | SoundBlanket® carried past the false ceiling line to the slab and down to the structural floor, sealed at both ends | Closes the flanking path over and under the partition |
| Sockets and service chases | Boxes offset into different stud bays, backed with SoundBlanket® offcuts and sealed | Stops a cut-out becoming the weakest point in the wall |
| The door in the wall | Solid leaf, EPDM perimeter seal and a bottom seal | The wall performs like its worst element, and that is almost always the door |
Figures are for the products, not for the finished wall. The rating of an assembly depends on the studwork, the boarding and the workmanship as much as on what we supply, and an assembly figure is the scope of an acoustic consultant.
03 / Sizes, grades and fixing
What to order, and how it goes on the wall
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Picking the face for the room
The blocking layers are much the same everywhere. The face is where the room type decides the specification, because it sets both the absorption and the look.
- Offices and meeting rooms: PET felt, NRC 0.50 at 18 mm, 40 plus colours, CNC cut or printed
- Classrooms and auditoria: wooden slats, NRC 0.75, EN 13501-1 Class B s1 d0
- Studios and theatres: BassBloc® behind the face, Bass Trap Mega in the corners, NRC 1.0
- Where the wall must read as joinery: fluted NRC 0.60 or perforated NRC 0.70 on oak veneer
- Where a flush upholstered face is wanted: fabric-wrapped panels, NRC 0.90 to ASTM C423
Sizes and thicknesses as supplied
| Layer | Thickness | Sheet or roll size |
|---|---|---|
| SoundBlanket® MLV | 1 to 10 mm, standard 2.5 and 4 mm | 8 x 4, 16 x 4 and 32 x 4 ft |
| BassBloc® | 20 and 40 mm | 1800 x 900 mm rolls |
| PET felt panels | 9, 12, 18 and 24 mm | 1220 x 2440 mm, up to 3000 x 2000 mm made to size |
| Wooden slats | 14, 16 and 18 mm | 2440 x 192 mm and 2440 x 128 mm |
| Wooden fluted | 18 mm | 1200 x 600 mm |
| HDHMR substrate | 8 to 24 mm | Century® HDHMR, HDF and MDF, 150 plus laminate shades, FR grade on request |
- LEAD TIME
PET felt panels 3 to 7 days. SoundBlanket® dispatches in 2 to 5 days within India, 7 to 10 days for export.
- FIXING
SR adhesive at about 20 ml per sq ft, or spray adhesive for panel work. Mechanical fixing through to the substrate where the panel is heavy or the wall is high.
- COVER BASSBLOC
BassBloc® is a cavity product. It goes behind board, felt or a perforated face and is never left exposed as the finished wall surface.
04 / What we see go wrong
Five ways a wall budget gets wasted
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Absorption bought as insulation
Panels go on the room face and the complaint stays exactly the same, because the neighbour was never the room's reverberation. Absorption and transmission are different problems and the products for them are different products.
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The partition stopped at the ceiling grid
Everything above the tiles is one continuous void, so speech from the next cabin arrives over the top of a wall that was specified correctly. The blocking layer has to be carried to the structural slab.
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Sockets cut back to back
Two boxes in the same stud bay, facing opposite rooms, leave a hole through both leaves with only a plate over it. Offsetting the boxes and backing them costs nothing while the wall is open.
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An empty cavity
A double leaf wall with nothing in the cavity can perform worse at some frequencies than a single leaf. The cavity has to be filled and damped for the second leaf to be worth building.
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The door left as it was
A hollow leaf with an undercut sits in the middle of the wall you just paid for and sets the result. Seals and a solid leaf are the cheapest part of the job and usually the one that is skipped.
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 |
| Echsorbix PET felt panels | NRC 0.30 at 9 mm, 0.40 at 12 mm, 0.50 at 18 mm, 0.60 at 24 mm | ASTM C423 / EN ISO 354 |
| BassBloc low-frequency absorber | NRC 0.85 at 20 mm, 0.95 at 40 mm; 100 kg/m³ | ASTM C423 |
| MMT Acoustix acoustic foam | NRC 0.90 at 50 mm (Pyramid); 0.95 at 50 mm (Galaxy) | ASTM C423 |
| SoundaXe wooden acoustic panels | NRC 0.75 (slats); 0.70 (perforated); 0.60 (fluted, 18 mm) | ASTM C423 |
| Fabric-wrapped acoustic panels | NRC 0.90 | ASTM 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 every layer above at the Palwal plant, Haryana
- Turn a wall section and an area take-off into a specified build-up and a priced BOQ, usually within 48 hours
- Supply test reports, technical data sheets and specification text for the build
- Make panels to size, in custom colours and prints, with CNC cutting
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We do not
- Carry out on site acoustic consultancy or measurement, and we do not certify a finished wall
- Install. We manufacture and supply the system
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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 the drawing.
Questions