The standard covers requirements, conditions, and procedures for threshold-of-hearing measurements in a sound field. However, the standard may also be used for conducting other sound-field hearing tests and as a research tool for assessing the effects of listening conditions and headgear worn by the listener on detectability of various test signals. Three sound fields are referenced in the standard: the free sound field, the quasi-free sound field, and the diffuse sound field. The test signals covered by the standard are frequency-modulated tones (warble tones) and narrow-band noises. However, other calibrated signals that meet requirements of this standard may also be used. The standard applies to binaural Iistening to test signals presented by one or more loudspeakers in a test room. Monaural air conduction hearing thresholds may also be determined if the opposite ear can be properly occluded. Special application of the standard to the assessment of spatial hearing is presented in Annex B.