Are media walls soundproof?

A media wall adds a cavity, not mass. The framing stands 200 to 300mm forward of the existing wall, so you end up with an air void running the width of the room behind a single 12.5mm skin of plasterboard. Left hollow, that void behaves like the body of a drum. Your subwoofer excites the air inside it, the board flexes in sympathy, and low frequencies come back louder and muddier than they were before the wall existed. Timber studwork with one 12.5mm board manages roughly 30 to 35 dB on its own, and filling the stud with mineral wool is worth another 5 dB or so.

Approved Document E does set figures for sound between homes: 43 dB DnT,w + Ctr for a wall in a converted flat, 45 dB in new build. Both are measured on the finished building, on the structure that separates two dwellings, and neither applies to a stud lining bolted in front of an internal wall. Part E will never be tested on your media wall, which is why empty ones get built, signed off and lived with. Nobody selling media walls says this part out loud: the build is not acoustically neutral. Skip the insulation and you hear the hollowness on dialogue, you feel it on bass, and so does whoever lives behind the plaster.

No, and it is worth being blunt about why. Slatted oak on a felt backing is an absorber. It takes energy out of the reflections bouncing around your own room, so reverberation shortens and the room feels calmer to sit in. That is a real benefit, and it is why slatted panelling is still the finish most of our clients ask for. What it does not do is help your neighbour. Absorption and insulation are two different jobs. One tidies up the sound inside the room, the other stops sound crossing a boundary, and 21mm slats on a 9mm backing board have neither the mass nor the airtightness for the second. Any advert telling you slats cut noise between rooms is selling something the material cannot do.

The cavity is open for about two days. Framing and first-fix wiring fill that window, then the boards go on and the void disappears behind tape, skim and paint. Insulation fitted while it is open costs £150 on a Clapham terrace, and we add it there as standard. In a converted flat it is £200, and mass-loaded vinyl goes behind the plasterboard on the shared side as well. Between them they cut the television bass reaching next door by 60 to 70%. On the Premium Cladding tier at £5,500–£7,000 the Rockwool RWA45 is already in the price rather than charged as an extra.

Retrofitting is what makes the deadline bite. Once the wall is skimmed and clad, getting insulation into the void means stripping boards, replastering and redecorating the whole feature, so a £150 decision turns into a rebuild. That is why we push it at survey. What we will not do is sell you soundproofing a media wall cannot deliver. Real isolation means decoupling: resilient bars, independent studwork, twin layers of acoustic board, an airtight perimeter. Different project, different price. If the noise you want gone is a neighbour's television coming through a party wall, a media wall is not the fix.

Most of the sound quality lost inside the room goes at the opening rather than in the wall. A soundbar set back behind a lip or a run of slats has its output filtered by whatever sits in front of it, and an up-firing Atmos bar loses the ceiling bounce it depends on the moment anything overhangs the top of it. So we size the opening around the specific bar, sitting it flush or a couple of millimetres proud, nothing across the top, no decorative slats in front of the drivers. The Bespoke Joinery tier at £4,500–£5,500 carries a soundbar mount with concealed cabling, and the position gets fixed at survey against the model you already own.