Contribution
Perceived Level Differences At Equal Loudness In Headphone-Based Comparisons Of Virtual Room Acoustics And Diotic Stimuli
* Presenting author
Abstract:
The "missing 6 dB" level difference at equal loudness between loudspeaker and headphone presentations has been studied for nearly a century, yet its origin remains unknown. Virtual reality (VR) offers new ways to examine this discrepancy in controlled settings. A preliminary study used virtual acoustic environments (VAEs) to replicate the level difference between diotic signals and room acoustics, as observed in real anechoic rooms (Denk et al., 2021). Factors like static binaural synthesis and visual reinforcement were tested, revealing 360° photos of Oldenburg and Aachen anechoic rooms, as well as a black screen, did not affect level differences at equal loudness (LDEL). This prompted further investigations in an interactive 3D virtual environment.Hence, in the current study, a 3D-rendered virtual replica of the VR lab at Oldenburg University was presented via head mounted display(HMD). Narrow-band third-octave noise convolved with KEMAR binaural room impulse responses (BRIRs) including different head-above-torso orientations (HATOs), were presented using dynamic binaural synthesis and compared to diotic stimuli. The subjects performed a loudness matching task to indicate which presentation was perceived as louder. This approach investigates if a dynamic, interactive VR environment and dynamic binaural synthesis affect LDEL in a different way than static binaural synthesis.