Originally Posted by ijansch
1) should there be absorption material behind the speakers or only fill up the space between them? (There’s nothing behind the concrete wall, just the earth outside, so insulation isn’t a requirement)
2) if the front of the speaker is flush with the wall, how do I deal with ventilation of the speakers?
3) should I decouple the baffle wall from floor, ceiling and walls, or can I just mount it directly, if I decouple the speakers from the wall using padding?
4) should I embed the subwoofer(s) in the wall too, keep them completely separate, or put them in the wall but with plenty of space around them?
5) are there benefits to putting the baffle wall and/or the subs on a platform, or can they be placed directly on the floor? (On the concrete or use padding?)
Let me preface my remarks by saying I've worked on theaters with baffle wall designs from 4 different " Professional Home Theater Experts" they each have their secret sauces some are similar some are different.
First baffles walls can be grouped into two categories Full wall, and Baffle Wings with big openings for speakers and acoustical benefits of using the area behind the baffle wall as a bass absorber.
1) Either style requires insulation behind the baffle wall and treatment on the front surface facing the room, With the full wall it is to damp cavity resonances and you don't have to fill it totally. With the baffle wings you want to have a filled area 12 inches deep or more with low density fiberglass. That area will act as a bass absorber.
2) I've never seen a baffle wall that required ventilation, you should pick speakers that are sealed or have their ports on the front face of the speaker. I notice one of your choices can be ordered either way. The speaker should be flush with the acoustic treatment on the wall not flush with the hard surface.
3) build the walls solid, no need to decouple, use multiple layers of material with Green Glue dampening. Decouple the speakers from the wall and seal the areas around the speaker with rubber gasket to make it airtight. You can actually build sand filled stands to set the speakers on behind the walls.
4) Subs can be in the wall assuming any ports are on the front. In the case of the baffle wings they just sit on the floor in the big openings under the wings and the direction of the ports is less important.
5) the benefit of a platform is only to isolate speaker vibration from the floor. It needs to use dampening construction methods like sand, layers with GG or both. For simplicity you can just place your subs on thick rubber pads. You can do a stage for looks if you want and it can be under or in front of the baffle wall.
It will be important that you consider speaker placement and angles carefully, if your speaker designer says the L/R should be angled toward the MLP you should implement that in the baffle wall.