Inwall speakers and In-ceiling speakers typically do not need to have boxes built or spaces constricted. These types of speakers are designed with American homes in mind. That means that the makers of these speakers know that your house uses 2 x 4 studs, that our standard stud placement is 16″ on center apart (14 1/2″ of space in between studs), our walls are at least 8 feet high, and our ceiling spaces are either attics or joist type structure in between floors. That means our walls have greater than 3 cubic feet of airspace and ceiling spaces even more than that.
So if I was a maker of speakers, I would make sure that my speakers sound good in those spaces without any modification. And that’s exactly what they do. Most all in wall and in ceiling speakers are Infinite Baffle design. In true infinite baffle designs, the front wave output of the woofer is separated from the rear wave output of the woofer with the air mass behind the woofer does not assist the mechanical operation of the woofer.
When you constrict an infinite baffle design’s airspace behind, you basically squeeze the speaker from behind and limit the movement of the woofer (the larger speaker on the plate) and that lowers the amount of bass (low sounds) coming from the woofer.
Think of it this way: say you have a glass of water and you are sipping it from a straw. If you place the straw in the free water and suck, you get a nice full stream of water. Now, instead of placing it in the water directly, you keep a little water in the straw and you put your finger over the other end. Try sucking now. What happens? The water can’t move to your mouth and the straw collapses.
So when you ask yourself whether or not you should be building a box, relax. We’ve already thought about how they are going to be installed, and they’ll sound great.