How wearing headgear affects measured head-related transfer functions

Predicting Perceptual Transparency of Head-Worn Devices

“…Measurements with head and torso simulators wearing several HWDs designed for AR applications have previously been conducted to assess their introduced acoustic impairments objectively. Whereas some studies have focused on analyzing the head-related transfer functions (HRTFs) in anechoic conditions [5,[8][9][10], other studies concentrated on binaural room impulse responses (BRIRs) [4,6]. In principle, these measurements contain the necessary information to characterize the HWD-induced effect.…”

“…In principle, these measurements contain the necessary information to characterize the HWD-induced effect. However, evaluations have mostly focused on calculating the frequency-averaged magnitude ratio between the transfer functions of the dummy head with and without the HWD fitted on it [4,5,[8][9][10][11] and calculating the changes to interaural time and level differences as a measure of horizontal localization impairments [5,8,10,11]. Perceptual study findings and objective metrics should be related to each other to estimate the impairments introduced by HWDs using computational models.…”

“…In terms of passive AR-related HWDs, several authors have published measurements of HRTFs with head and torso simulators wearing different headphones [8,9,15] and head mounted displays [8,10,5]. BRIRs were measured in [4,6] in a similar manner, taking into account the effects of the room.…”

“…BRIRs were measured in [4,6] in a similar manner, taking into account the effects of the room. So far, in most investigations, a measure of transparency has been calculated as the ratio between the smoothed magnitude response of a real or artificial listener when wearing the headphones and listening with open ears [4,[8][9][10]5]. It is clear that such measures only serve as a rough indication of coloration and do not comprehensively reveal the induced perceptual impairments.…”

Optimizations of the Spatial Decomposition Method for Binaural Reproduction

“…To enable direct comparisons between loudspeakers and binaural renders we used non-occluding headphones (AKG K1000). Although the occlusion from these headphones is arguably smaller than with generic on-ear or over-the-ear headphones, a comparison showed that they exhibit differences of 6 dB at 10 kHz when comparing HRTFs with and without headphones [41]. As the occlusion effect of the headphones is direction dependent, one possible way to compensate for them would be to render the BRIRs using HRIR datasets measured on subjects wearing the headphones.…”