**Appendix**

Readers have the possibility to see how the Titan data (**Figure 3A** and **B**) can be manipulated in 3D, in order to observe other aspects of the 3D-WBT graph, collapsing one axis in order to see the absorbance at a particular stimulus frequency. The corresponding videos can be downloaded from the OAE Portal at the address:

http://www.otoemissions.org/index.php/en/?option=com\_content&view=article&id=261
