Abstract
At the beginning of the twentieth century, the physicist Erich Waetzmann had already identified limitations in the functionality of the human ear in his “School of Listening”,Footnote1 where he provided instructions on “how the severely neglected auditory organ could be trained and strengthened in its performance”,Footnote2 when compared to our sense of sight. Therefore, he decided to address the shortcomings of the auditory sense with his booklet.