Absolute HRTF magnitude errors (left ear) and interaural phase delay errors, averaged across 110 directions in an approximate Lebedev grid. HRTFs were interpolated from truncated SH-HRTFs (Trunc method) for five different spatial orders (1, 10, 20, 30, 44). The dotted lines indicate an approximation of the just noticeable differences: 1 dB for magnitude and 20 μs for phase delay.