How we make our panels

The layers

1. 1

   Fabric

   The face of the panel is an acoustically transparent fabric. Its even, open weave lets sound waves through without reflecting them, so they reach the wool. If the fabric were as tight as a blackout curtain, some of the sound would bounce straight back into the room and the panel would work less well, especially at higher frequencies. We stretch the fabric over the frame by hand and stitch it at the back rather than gluing it. That keeps the face smooth and the corners neat, and there’s no glue inside to clog the wool.

2. 2

   Veil

   Under the fabric is a veil – a thin non-woven layer over the face of the wool. It does two jobs. It keeps the fine wool fibres inside the panel so they can’t work through the weave, and it hides the wool: a light fabric laid straight on the wool could let it show through slightly. So light colours get a white veil and dark colours a black one. The veil is thin and open enough not to change how the panel absorbs sound.

3. 3

   Rock wool

   Inside the panel is a slab of rock wool. Sound travels in between the fibres, moves the air in their dense web and loses energy to friction – it turns into a tiny amount of heat. Rock wool works across a wide range of frequencies and doesn’t sag over time. The 5 cm panel has one layer, the 10 cm panel two. The thicker panel reaches further down, because low-frequency waves are longer and need more material to lose their energy.

4. 4

   Frame

   The frame is made by a joinery workshop we work with in Warsaw, to the size in your order. We use pine or spruce: it’s light, stable and holds staples well. The front edges are rounded so the fabric can’t wear through on a sharp corner and the panel’s edges look soft. Large panels get a crossbar, which stops the frame twisting while the fabric is stretched over it and later on the wall.

5. 5

   French cleat

   At the back, the panel has a black non-woven cover and a wooden French cleat. That’s two battens cut at an angle: one is screwed to the panel, the other to the wall. You hang the panel by dropping one behind the other, and its weight holds it against the wall. The cleat also keeps the panel off the wall, leaving an air gap behind it. Sound that has passed through the wool reflects off the wall and goes through it a second time, which helps with lower frequencies.

Popular polyurethane foam panels are usually a few centimetres thick with a wavy surface. That kind of foam deals well with high frequencies, but mid and low frequencies pass through it almost unchanged. The room gets quieter on sibilants, while voices still sound boomy and hollow.

Rock wool 5–10 cm thick absorbs a broad band, from the mid frequencies of speech up to the highs, and the 10 cm version reaches lower too. It’s the same principle that acoustic treatment in recording studios relies on: a dense, porous material of the right thickness behind a fabric that lets sound through.

Packing

Every panel is packed on its own. The corners get protectors and the box is sized to the panel, so it can’t shift around in transit.