146th Meeting of the Acoustical Society of America, Austin, TX, USA, 10.-14.11.2003.
Part Ib: Effects of eye-glasses, hair, headgear and clothing on measured head-related transfer functions
Klaus A J Riederer
Laboratory of Acoustics and Audio Signal Processing
Helsinki University of Technology (HUT)
P.O. Box 3000, FIN-02015 HUT, Finland
Tel: +358 9 451 2494; Fax +358 9 460 224
Email: Klaus.Riederer@hut.fi, URL: http://www.hut.fi/~kar
Extensive head-related transfer function (HRTF) measurements show high HRTF repeatability, consequences of different measurement methods and conditions covering the whole three-dimensional space [Riederer, J. Audio Eng. Society (Abstracts), 46, p. 1036 (1998 Nov.), preprint 4846]. This study concentrates on specific effects on HRTFs carefully re-measured on the same Cortex dummy head applying Sennheiser KE4-211-2 microphones at its silicone putty blocked ear-canal entrances, employing 252 sound incidents including seven elevations. The effects of five different wigs (synthetic, natural, thick, thin, long and short hair) with varied hairstyles, four hats (cap, bicycle helmet, men’s and women’s trilby), clothes (alpaca pullover, bicycling drymax-jacket) and spectacles were investigated under 28 combinations. The influences are highly dependent on direction, frequency and case. Clothes and eye-glasses affect minimally HRTF; hair has a stronger effect, depending on the actual hairdo (typically above 7 kHz). Hats alter intensively HRTFs (typically above 5 kHz), depending on the model. The measurements give deeper insight to the development of idiosyncratic features in binaural localization cues. The second part of the study addresses their perceptual effects [Riederer, J. Acoust. Soc. Am., this issue]. [Work supported by Graduate School of Electronics, Telecommunication and Automation; thanks to Finnish Broadcasting Company, Mr. Hellstrom; Mrs. Chen.]