Internality

An environment descriptor in audio assessment. The distinctness to which a sound source, ensemble or scene is perceived inside the head. Distinctly internal means that a sound is unambiguously perceived within the head. Distinct external means that a sound is unambiguous perceived outside the head. If it is ambiguous whether the sound is perceived to be inside or outside of the head, the internality is Indistinct. A dry sample played equally to both ears over headphone may be perceived inside the head. Naturally occurring sounds are generally perceived externally. Scale applied in listening tests: Distinctly internal- Indistinct - Distinctly external [Reference: Report ITU-R BS.2399-0]