Frequency response of headphones measured in free field and diffuse field by loudness comparison

• Published in: Journal of the Acoustical Society of Japan (E) Vol. 12; no. 3; pp. 131 - 138
• Main Authors: Hirahara, Tatsuya, Ueda, Kazuo
• Format: Journal Article
• Language: English
• Published: Tokyo Acoustical Society of Japan 1991
• Subjects: Acoustical measurements and instrumentation; Acoustics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Headphone; Hearing threshold; Loudness comparison; Physics; Real-ear frequency response; Measurement; Free field; Diffuse field; Perception threshold; Sound intensity; Frequency response; Headphone
• ISSN: 0388-2861; 2185-3509
• DOI: 10.1250/ast.12.131

Loudness comparisons were performed by four subjects, under two experimental conditions: free field (anechoic room) and diffuse field (reverberation room). Each subject adjusted the headphone level of critical band noise bursts until they were equally loud as those from a reference loudspeaker (70dB SPL). Measurement scatter was smaller in the diffuse field than in the free field. To examine the reliability of loudness judg mentsat high frequencies, another method-hearing thresholds by Bekesy tracking-was employed. Each subject's threshold was measured with both loudspeakers and head phones.After compensation was made for the loudspeaker and room transfer functions, headphone frequency response was extrapolated from the results. This method led to high-frequency responses similar to those from loudness comparison. A loudness comparison experiment in which the subjects continuously wore a headphone was performed. However, the method of sound pressure loss measurement should be reconsidered.