Fig 1.
Photography (left) and screenshot (right) of the acoustic reproduction system in the real and in the virtual environment (RE and VE).
The loudspeakers are numbered in azimuth and color coded in elevation.
Table 1.
Overview over the conditions considered and grouped into blocks.
Conditions were randomized within blocks. The conditions varied in available visual information, target stimulus and if the head-mounted display was worn.
Fig 2.
Pointing bias in azimuth (squares) and elevation (circles) for each subject.
The bias was calculated as the mean error over all source locations in the two visual localization conditions. Negative angles indicate biases to the left and downwards for azimuth and elevation, respectively.
Fig 3.
Spectral difference (SD) measured at the left ear of the B&K HATS with and without the HTC Vive.
The angles in the legend represent the elevation angles considered in the current study. The SD was calculated in auditory bands and averaged over three frequency regions at low-, mid- and high frequencies as shown in the legend.
Fig 4.
Signed errors of interaural differences in level and time (ILD and ITD) with respect to azimuth angles on the horizontal plane (0° elevation).
Positive errors indicate larger ILDs and ITDs with than without the HMD. The ILDs were calculated in auditory bands and averaged over three frequency regions at low-, mid- and high frequencies as shown in the legend. The ITDs were calculated from the delays between the broadband binaural impulse responses (see Methods for details).
Fig 5.
Response plot of the visual localization experiment for the real and virtual environment.
The black squares represent the source locations. The small markers show the responses of the subjects and the large markers the mean response over subjects and repetitions. Negative angles represent sources to the left and downwards for azimuth and elevation, respectively.
Fig 6.
Mean absolute (circles) and signed (boxplots) azimuth error for visual localization in the virtual (light blue) and the real (dark blue) environment.
The error is shown over the thirteen azimuth angles in the horizontal plane (0° elevation). The boxplots indicate the median (line) and the first and third quartile. The whiskers extend to 1.5 times the interquartile range.
Fig 7.
Mean absolute (circles) and signed (boxplots) azimuth error for acoustic localization of blind-folded subjects with (light grey) and without (dark grey) the head mounted display (HMD).
The error is shown over the thirteen azimuth angles in the horizontal plane (0° elevation). The boxplots indicate the median (line) and the first and third quartile. The whiskers extend to 1.5 times the interquartile range.
Fig 8.
Mean absolute (circles) and signed (boxplots) azimuth error for acoustic localization with varying visual information in the virtual environment and the real environment. In all conditions, except in the real environment, subjects wore the head-mounted display (HMD).
The conditions depicted with shades of blue color include visual information of possible source locations. The error is shown over the thirteen azimuth angles in the horizontal plane (0° elevation). The boxplots indicate the median (line) and the first and third quartile. The whiskers extend to 1.5 times the interquartile range.
Fig 9.
Absolute elevation error in degrees for acoustic localization for blind-folded subjects with (light grey) and without (dark grey) the head mounted display (HMD).
The error is shown over the three elevation angles and includes the sources from all azimuth locations. The boxplots indicate the median (line) and the first and third quartile. The whiskers extend to 1.5 times the interquartile range.
Fig 10.
Absolute elevation error for acoustic localization with varying visual information in the virtual environment and the real environment.
In all conditions, except in the real environment, subjects wore the head-mounted display (HMD). The conditions depicted with shades of blue color include visual information of possible source locations. The error is shown over the three elevation angles and includes the sources from all azimuth locations. The boxplots indicate the median (line) and the first and third quartile. The whiskers extend to 1.5 times the interquartile range.