This is Newell's most famous contribution to studio architecture. In a Non-Environment room:
Loudspeakers are flush-mounted (soffit-mounted) in the front wall to provide a large baffle, which improves low-frequency efficiency and uniformity. recording studio design philip newell pdf download best
If you are serious about studio construction, by Philip Newell is arguably the single best resource available. For a "best" experience, I recommend the 3rd Edition (published around 2011), as it includes updates on modern digital processing and newer acoustic materials. This is Newell's most famous contribution to studio