Sound localization cues generally include
interaural time difference (ITD), interaural intensity
difference (IID) and spectral cues. The purpose of a series
studies in this book is to investigate the important
spectral cues involved in so-called head related transfer
functions (HRTFs) using a combination of HRTF analyzes and a
virtual sound localization (VSL) experiment. Previous
Psychoacoustical and physiological studies have both
suggested the existence of spectral modulation frequency
(SMF) channels for analyzing spectral information (e.g. the
spectral cues coded in HRTFs). SMFs are in a domain related
to the Fourier transform of HRTFs. The relationship between
various SMF regions and sound localization was tested here
by filtering or enhancing HRTFs in the SMF domain under a
series of conditions using a VSL experiment.The overall
results highlighted the relationship between SMF region and
sound localization in the vertical plane. Knowledge of the
influence of manipulations in the SMF domain on sound
localization has implications for the application of
various signal processing algorithms and models of monaural
and binaural hearing.