Externalization of Virtual Sound Sources With Bone and Air Conduction Stimulation.
Jie Wang, Huanyong Zheng, Stefan Stenfelt and 3 others
PMID 40961260WHAT IT FOUND
Bone conduction headphones externalized virtual sounds as well as air conduction when reverberation was present.
Contralateral ear reverberation drove this effect more than the ipsilateral ear. This supports bone conduction for spatial audio in VR, though the study used only nine listeners.
Key findings
01Externalization scores for bone conduction were as high as those for air conduction when identical signals were used.
02Reverberation energy at the contralateral ear had a greater impact on externalization ratings than energy at the ipsilateral ear.
03Increasing reverberation improved externalization, but this effect plateaued beyond a certain duration, suggesting a saturation point.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study included only nine participants, limiting the generalizability of the findings. Only a single sound source azimuth (45 degrees) was tested, so results may not apply to sounds coming from other directions. The study used non-individualized BRIRs, which may not reflect the acoustic experience of patients with specific head or ear geometries. Bone conduction cross-talk characteristics were unknown, preventing the calculation of key acoustic parameters (DRR, FFV, IC) directly from the cochlear signals for the BC conditions. The virtual room environment did not match the actual semi-anechoic listening room, although this mismatch was consistent across all conditions.
Declared interests
The authors disclosed receipt of financial support from the National Natural Science Foundation (grant numbers 11974086, 12074403, and 12410750).
The easy way to misread this
Do not assume bone conduction devices are superior for spatial audio in all contexts. The study found no difference between air and bone conduction only when reverberation was present; in anechoic conditions, bone conduction's reduced interaural time differences may impair localization. Additionally, the study used normal-hearing participants and a single 45-degree source, so it does not confirm how patients with hearing loss or different sound environments would perceive spatial cues.