Should this be done with the drywall.....or with the wood slats. I ask because you had mentioned making sure the slats are sealed tight to the drywall....so I am wondering how this angle attachment is done without an air gap.
Well, you still need a gap behind the slats! They must be on some type of frame that angles away from the wall a bit, to create the depth behind them. It's the FRAME that has to be sealed to the wall.
A slot wall is basically just a large Helmholtz resonator: A restricted gap over an airtight cavity. In this case, the restricted gap is the slot between the slats. There is a "slug" of air stuck in that gap, that vibrates in and out in sympathy with a certain frequency that is set by the dimensions of the slot and the depth of the cavity behind. One common way of describing how it works is blowing across the top of a Coke bottle, to make the bottle hum. That's the perfect example of a Helmholtz resonator. The "slug" of air trapped in the neck of the bottle vibrates up and down the neck, and the frequency is set by the dimensions of the neck and the depth of the cavity inside the bottle. Put water in the bottle and the note changed, because the depth changed.
But if the cavity is not sealed, then it won't work. If you cut the neck off a Coke bottle and blow over it, it won't hum, since there is no cavity, even though the neck is identical. Same if you just cut a hole in the bottom of the bottle. The cavity has to be sealed. So your slats have to be mounted on the front of some kind of box, or at least on a frame that is sealed to the wall, and is itself sealed all around.
That's what I meant when I said that the slot wall must be sealed to the underlying drywall, if it is just a frame with slats on it. But if it is a complete box that already has a back on it, then of course it is the box that must be sealed, and it doesn't matter if you also seal it to the wall or not.
The reason why you might want to just build a frame with no back on it and seal it to the wall, is money! The back needs to be a thick, heavy, rigid piece of wood, and that costs $, so if you already have a good isolation wall there with two or more layers of 5/8 drywall on it, then you can skip the back on the box, and use the drywall instead.
- Stuart -
