Detection of reflections in free-field directional hearing by waveform analysis of accurate dummy-head HRTFs

The human spatial hearing and localisation investigations often need non-reverberant environment. In these so called "free-field" situations we try to avoid reflections, e.g. by making the recordings in the anechoic room. An analysis in the time-domain based on the impulse response has only low SNR, but measurements of transfer functions using a noise excitation have increased accuracy and SNR. This paper shows a simple method using waveform analysis in the frequency domain to find the location and effects of reflecting surfaces, and an example of using the difference of head-related transfer functions in spatial hearing applications.