kettle drum

In an automatic musical instrument (especially a piano orchestrion) an effect obtained by alternately striking two small beaters to the left and right of the larger bass drum beater on a bass drum head. The term, which should be "kettle drum effect," as no separate drum is used, is found widely in orchestrion literature-nearly all of Seeburg’s descriptions of large orchestrions and photoplayers, for example. * Synonyms: tympani, timpani.