Described embodiments include a method that includes inserting an ablation catheter into a Eustachian tube of a subject, and, using the ablation catheter, while the subject is awake, passing an ablating signal, which is audible to the subject, through epithelial cells that line the Eustachian tube, while controlling an amplitude of the ablating signal responsively to a loudness of the ablating signal as perceived by the subject. Other embodiments are also described.