Lower (L) and upper (U) thresholds of insignificant RMS errors for single- and two-sided testing as a function of the number of loudspeakers and trials.

The total angle span of the speaker arrangement was 180° or 140° (angle span) and the speakers are separated by angles between 90° and 10° (angle between speakers). Every speaker is to be set as target and the random selection is repeated 2 to 20 times (repetitions). The number of trials (test runs) is determined by the product of the number of loudspeakers and the number of repetitions.