Room correction measures the combined speaker + room response at the listening position using a calibration microphone, then generates inverse filters to flatten the frequency response and align phase. Popular systems: Sonarworks SoundID, Dirac Live, IK Multimedia ARC, and Genelec GLM (built into their monitors).
Room correction works best above the room's transition frequency (~200–300 Hz). Below that, physical acoustic treatment (bass traps) is more effective because DSP cannot fix acoustic cancellations (nulls). The best results come from combining moderate acoustic treatment with room correction — not relying on either alone.