Drawing of the user interface at the end of a unsupervised block of 15 letters (30 trials).

<p>The target text in the first line is always present for the subject. Text spelled with the unsupervised method appears letter-by-letter in the second line, and the text after re-analysis with the posthoc method is shown in the third line. In the lower part of the screen, circle positions visualize the auditory scene from a top view. Each circle encodes one out of six tones/tone directions relative to the user, who is positioned in the middle of the ring of speakers (fixation cross). After selecting a group of letters (duration: one trial), the user virtually moves into the corresponding circle and can select a letter from within this circle by a second trial.) The result shown in this figure corresponds to the first unsupervised block of subject <i>nbf</i>.