I'm planning to build a shed studio with concrete walls, no windows and a drop-down ceiling, and I'm concerned that I won't have enough sound reduction from the outside. Will it be necessary to build a 'room within a room' to achieve decent soundproofing?
Joe Weiderhold
Editor In Chief Paul White replies: You won't need a room within a room, but it's a good idea to plan for a heavy ceiling with at least two layers of plasterboard and heavy rockwool insulation above. Suspended office ceilings don't do much for soundproofing, as they are fairly thin and have nothing above them. Also, the door would be better doubled up — one door opening outwards and the other inwards — separated by the thickness of the wall. Fit seals to the doors on all four sides, to ensure an airtight fit.
The concrete shell can be lined with double plasterboard layers on battens with rockwool insulation. This will provide very adequate isolation. If you want to record drum kits, consider making a floating plinth of chipboard resting on 30mm-thick, high-density rockwool insulation slabs. You'll need acoustic treatment to stop the room sounding too live, but a few panels of 30mm or thicker rockwool slabs, covered in thin fabric and hung from the walls, ideally with an inch or two of air gap behind, should do the trick.
To maintain a healthy supply of oxygen, you'll need some ventilation, and probably air conditioning too, as it will get very hot during summer. It's also a good idea to install a dehumidifier, as this will keep your equipment condensation-free in the winter.
As you will know, we run monthly Studio SOS features where the SOS team visit readers' home studios and tackle some of their niggling issues. More often than not, these features offer advice on acoustic treatment. I'd also specifically recommend that you take a look at 'Making Rooms', from SOS July 2000 (www.soundonsound.com/sos/jul00/articles/faqacoustic.htm), and our five-part 'Practical Acoustics' series that ran in SOS from July to November of 1998.