Loudness Mismatch between Headphone and Loudspeaker Presentation Revisited: Effects of the Room and Interaural Correlation
Résumé
Since the 1930s, a mismatch between headphone and loudspeaker presentation has been repeatedly observed: The sound pressure level at the eardrum generated by a headphone has to be about 6 dB higher compared to a free-field source to elicit the same perceived loudness. While it has been shown that this effect vanishes if the same waveforms are generated at the eardrum in a blind comparison, the origin of the mismatch is still unclear. We present new data on the issue to systematically characterize this mismatch under variation of the stimulus frequency, presentation room, headphone type, and binaural parameters of the headphone presentation. Subjects adjusted the playback level of a headphone presentation to equal loudness as loudspeaker presentation; the individual levels at the eardrum were determined through appropriate transfer function measurements. Identical experiments were conducted at Oldenburg and Aachen with 40 normal-hearing subjects, including 14 that passed through both sites. Our data verifies a mismatch between loudspeaker and diotic headphone presentation, especially at low frequencies. This mismatch depends on the room acoustics of the loudspeaker presentation, and on the interaural correlation in both presentation modes. Effects of the headphone type are presented by Llorca-Bof� et al. at this conference. Funded by the Deutsche Forschungsgemeinschaft (DFG) ? Projektnummer 352015383 ? SFB 1330 A4.