The Collaborative International Dictionary of English v.0.48:

Tympanist \Tym"pa*nist\, n. [L. tympaniste, Gr. tympanisth`s.]
   One who beats a drum. [R.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

tympanist
    n 1: a person who plays the kettledrums [syn: tympanist,
         timpanist]