For the last 30-40 years, loudspeaker design fashion has been mostly in favour of ported loudspeakers, which IMHO perform less well at the boundary compared to sealed box loudspeakers.
Sealed box loudspeakers perform much better at the boundary, but still require copious amounts of wall treatment at the boundary, for best performance.
Due to apartment living, our full-range, 3-way, sealed box loudspeakers perform superbly just 60mm from the from wall - on concrete-bolted iron L-hangers.
The wall treatment is 40mm of super-heavy synthetic toddler play-mat. Dead as a door-nail. Getting the mat secured to concrete apartment walls was more time consuming than mounting the loudspeakersā¦ but so worthwhile!
Would our loudspeakers perform better still 1m out from the wall? Probably, but itās not an option. 