Acoustic characterization of a Ukelin

An acoustical characterization was performed on a ukelin, a wooden hybrid stringed instrument designed to combine features of the ukulele and the violin. This instrument consists of two resonant cavities at opposite ends of the instrument, one supporting sixteen strings that are individually bowed, and the other supporting 16 strings arranged in groups of four-note diatonic chords that are simultaneously plucked with the free hand, allowing an individual player to produce a melody/accompaniment combination. The ukelin design was patented in the early 20th century and sold door-to door as a novelty instrument. Modal Analysis results of a sample instrument are presented and compared with an FEA normal modes solution using ANSYS. Preliminary results show good agreement of the mode shapes for several modes between the modal results and the ANSYS predictions, but a significant difference in mode frequencies for a given mode shape. The differences in frequency are attributed primarily to unknown material properties of the wood of the sample instrument. Implications of the use of a finite-element model and of the Dynamic Modification feature of modal analysis are discussed.