Left-ear magnitude spectrum of two circular grid HRTF datasets (top: d = 0.25 m, bottom: d = 1.50 m) as a function of frequency (abscissa) and source azimuth φ (ordinate). Comparing the spectrum of near- and far-field HRTFs reveals how a nearby source (top) leads to stronger high-frequency damping around the contralateral ear (φ = 270°) and increased magnitude around the ipsilateral ear (φ = 90°), also at frequencies below 3 kHz. This results in significantly higher ILDs (see Fig. 1, left).