3D printed dummy heads for crosstalk cancellation studies in bone conduction

Abstract

Thanks to affordable 3D printers, creating complex designs like anatomically accurate dummy heads is now accessible. This study introduces dummy heads with 3D-printed skulls and silicone skins to explore crosstalk cancellation in bone conduction (BC). Crosstalk occurs when BC sounds from a transducer on one side of the head reach the cochlea on the opposite side. This can disrupt binaural cues essential for sound localization and speech understanding in noise for individuals using BC hearing devices. We provide a step-by-step guide to constructing the dummy head and demonstrate its application in canceling crosstalk. The 3D models used in this study are freely available for replication and further research. Several dummy heads were 3D-printed using ABS for the skull and silicone skins of varying hardness, with a 3-axis accelerometer at the cochlea location to simulate inner ear response. Since the cochlea is inaccessible in humans, we targeted crosstalk cancellation at the mastoid, assessing if this cancellation extended to the cochlea within the dummy heads. We compared these results with our previous experiments conducted on seven human subjects, who had their hearing thresholds measured with and without crosstalk cancellation, to evaluate if the dummy heads could reliably replicate human crosstalk cancellation effects.