Experimental configuration employed in the binaural recordings and band diagram of the sonic crystal slab used on the experiments.

<p><b>(a)</b> Realistic 3D rendering of the sonic crystal slab, loudspeaker and one of the listener positions employed in the binaural recordings. <b>(b)</b> Schematic representation of the experimental setup and sound intensity map (for a noise band with central frequency 1.12 kHz, 1/3 octave bandwidth). The sound source position is shown by a loudspeaker icon on the top of the figure. For the recordings, the dummy head and the experimental subjects were placed on the black dots along the central line (a-d). The red and blue rays correspond to a geometric acoustics representation of the focusing by negative refraction. <b>(c)</b> Band diagram corresponding to the sonic crystal slab used in the experiments. The gray area on the band diagram delimitates a negative refraction band (central frequency 1.12 kHz, 1/3 octave bandwidth). The monaural intensity of this noise band was measured using a sound meter level and it is plotted as a colormap on panel (b). The insets is the first reduced Brillouin zone of the reciprocal space showing the points <i>X</i>, <i>J</i> and Γ that defines the directions of the wave vector in the reciprocal space (e.g. the Γ−<i>X</i> direction corresponds to the normal incidence in the direct space).