Speaker loudness.

Speakers were calibrated to equal loudness (58 dB). Before each session, the subject could adjust this loudness for individual speakers to have subjectively equal loudness. Most subjects did not make changes; only those that did are reported here. Subjects are grouped according to experimental rounds. Exp refers to the experimental round. Speaker location refers to the speaker labels given in Figure 1. -  =  unchanged, x  =  unavailable. All values are in dB.