Presentation for the "Models of Auditory Perception Seminar". This presentation is about the auditory system and, in particular, the inner ear. After explaining the mechanics of the cochlea in details, I am focusing on the Frequency-Place-Transformation, which takes place along the basilar membrane. This process is then closely connected to the so-called auditory filters and the masking effect. Finally, I am comparing how all these different scales are related to each other.