An extraaural headphone system for optimized binaural reproduction
Vera Erbes, Frank W. Schultz, Alexander Lindau, Stefan Weinzierl · MPG.PuRe (Max Planck Society) · 2012
The transparent binaural reproduction of virtual acoustic environments requires a headphone system with high spectral bandwidth, with a transfer function as linear as possible, a high signal-to-noise ratio (SNR), sufficient crosstalk attenuation and a frequency response which is robust with respect to repositioning and interindividually differing morphology [1],[2]. Additionally, for in-situ comparisons with real sound fields and for low-frequency extension with subwoofers, such a system should be sufficiently transparent to exterior sound fields and comply to the ’free air equivalent coupling’-criterion (FEC) i.e. approach the acoustic impedance of free air as seen from the ear canal entrances [1]. Moreover, it should be easy to perform an individual headphone transfer function compensation, e.g. with miniature in-ear microphones [3]. Finally, the system should be combinable with other technical components of virtual environments such as 3D shutter glasses, head mounted displays and head tracking sensors. For this purpose, an extraaural headphone system was developed (BK211, fig. 1), featuring an extraaural headset, an IIR-/FIR-filter DSP-system and a low noise power amplifier. Measurements show that the system fulfills the requirements specified above better than other commercially available headphones.