I'm just working on how I'm going to ventilate my soundproof studio room. Grateful for any tips/warnings etc.
The room will be free-standing, built from scratch at the end of my garden, with an outer leaf of 100mm concrete block and an inner leaf of plasterboard (drywall). I won't be floating the floor, but will instead use a "split foundation" design to decouple the two leaves of wall, with the outer one resting on a separate foundation running all the way round the inner one, with a 1cm gap between. The inner room will be sunk a foot into the ground, but the outer foundation will extend higher - to ground level - the extra depth giving it greater strength to make up for its narrow width.
The drawings below represent two variants of what I'm thinking for ventilation. They both involve two air-ducts made of flexible rubber coming out of the inner room, running down the space between the walls (which will be fairly wide at 15cm). These will then exit the outer room close to ground level, and the points where they exit will have little brick boxes built around them to minimize sound leakage. They will then be buried under ground: in the first plan they extend some way up the garden before surfacing; in the second they are just twisted around a few times before surfacing near the building.
I read in a few places that one wants to make air ducts have lots of turns and corners, as each of these reduces sound leakage. Is that right?
I figure I'll then attach a slow-moving exhaust fan to one of the duct-holes in the inner room, and an intake fan to the other.
I prefer the second idea as it keeps everything close to the building. But I am really making this up as I go (albeit on the back of some research and consideration), so if anyone's got any better ideas let me know!
External image, not preserved — original: http://www.soulpreservationsociety.com/Studio%20Plans/Ventilation.jpg
External image, not preserved — original: http://www.soulpreservationsociety.com/Studio%20Plans/Ventilation2.jpg