Triad in-wall.
There are two reasonable speaker placements:
1. Well into the room. The greater of 4' and half the distance to the listener is a nice start which will limit how deep the SBIR null is and get it down below 70Hz where a sub-woofer might fill in.
2. Flush with it. This gets rid of SBIR problems, eliminates edge diffraction, nets 3-5dB of more excursion limited headroom for a given number and size of bass driver, and increases efficiency and sensitivity by the same amount for a given cabinet volume and low frequency extension.
Studios often use soffit mounted speakers for these reasons, although you need a speaker designed for the placement so you don't get a lower midrange (and bass) boost that makes singers sound like they have chest colds and instruments boomy.
In-walls get a bad reputation because most are crap built for convenience (the smallest possible hole to cut in the wall) and not performance, sort of like Bose(TM) cubes but those problems don't exist with good designs having proper enclosures (well braced and heavy - you can have a 20 pound in-wall monitor cabinet, although the cut-out will be 2'+ high x 14" wide).
There are two reasonable speaker placements:
1. Well into the room. The greater of 4' and half the distance to the listener is a nice start which will limit how deep the SBIR null is and get it down below 70Hz where a sub-woofer might fill in.
2. Flush with it. This gets rid of SBIR problems, eliminates edge diffraction, nets 3-5dB of more excursion limited headroom for a given number and size of bass driver, and increases efficiency and sensitivity by the same amount for a given cabinet volume and low frequency extension.
Studios often use soffit mounted speakers for these reasons, although you need a speaker designed for the placement so you don't get a lower midrange (and bass) boost that makes singers sound like they have chest colds and instruments boomy.
In-walls get a bad reputation because most are crap built for convenience (the smallest possible hole to cut in the wall) and not performance, sort of like Bose(TM) cubes but those problems don't exist with good designs having proper enclosures (well braced and heavy - you can have a 20 pound in-wall monitor cabinet, although the cut-out will be 2'+ high x 14" wide).