Headphones expose translation and low-level faults that room-bound speakers hide
Headphone listening is ubiquitous, so a mix should be checked on them. Because they bypass the room, headphones expose low-level faults (clicks, bad edits, automation slips, the onset of digital clipping at the stereo edges) and are unaffected by room comb filtering and modes, acting as a safety net. Their drawbacks: the stereo image stretches to a 180-degree in-head picture and low-frequency extension is limited, so they supplement rather than replace speaker monitoring.
Examples
A mix approved on nearfields can reveal on headphones an edit click or a 3–5 kHz harshness previously masked by room acoustics.
Assessment
Describe two fault types headphones detect better than nearfields and one area where headphone monitoring is inherently unreliable.