Level difference at equal loudness between the level of the sound from one of the five positions in space (indicated on the abscissa) and the level of the reference sound (BPN3 for the BPNs; BBN for the BBN) presented from the frontal loudspeaker. Mean level differences (symbol) and the interindividual standard error (errorbars) are shown. The results for the BPNs are indicated with light blue circles. The number of the BPN is shown in the middle of the circle with 1 referring to the lowest and 5 referring to the highest centre frequency. The data for the sequential condition with the BBN are shown with orange squares. The data points for the different stimuli are shifted against eachother horizontally for a better visibility. The dashed line indicates the test and reference sound had the same loudness at the same level.