The word "tympanise" is pronounced as /ˈtɪmpənaɪz/ with a stress on the second syllable. It is spelled with a y instead of i, which is uncommon in English. The word derives from the noun "tympanum", which refers to a membrane in the ear, and '-ise' is added as a suffix to indicate the process of stretching or tightening. Tympanise is a verb and means to adjust or tension a membrane, especially the eardrum, for improved hearing or sensitivity.
To stretch, as the skin over a drumhead.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.