A target curve is the reference for room correction. Common targets: 'flat' (all frequencies equal — technically accurate but often perceived as bright in-room), the Harman curve (scientifically derived from listener preference: +3–6 dB bass shelf below 200 Hz, flat to 2 kHz, −2–4 dB treble above 10 kHz), and the B&K curve (flat to 2 kHz then gradual −3 dB/octave roll-off).
Most room correction systems default to a modified Harman-style curve. You can customize: more bass for enjoyment, less for mixing accuracy; more treble for detail, less for fatigue reduction. The best target curve depends on your speakers, room, listening distance, and preference.