The avoidable design errors that wreck great builds.
The most expensive mistakes are made before any speaker is chosen: wrong room shape, no acoustic shell, no isolation from adjacent walls, HVAC routed straight through the ceiling, and seat geometry that ignores sightlines. A reference home cinema is 60% architecture, 30% acoustics and 10% gear.
Specifying sensors before deciding response protocol, treating the command centre as a furniture exercise, and skipping drills. The fence is the easy part.