Measuring and evaluating a louder design of the musical instrument kantele

The kantele is a musical instrument excited by plucking. It is an ancient instrument, which is still used in traditional folk music in Finland, Northwest Russia, and the Baltic countries. This paper discusses analysis and measurement results of a modified kantele, designed to have an increased loudness. The design rules to make the modified kantele louder are also proposed. The conducted measurements confirm and support the proposed design rules. The main features of the traditional design of the kantele are described, so that the presentation of the design rules and analysis results could be understood. The design rules to make a plucked string instrument louder are (1) increase the tension of the string, (2) increase the radiation surface, and (3) isolate the top plate from the sound-box with an air gap. To some extent rules (1) and (2) are straightforward and familiar for most musical acousticians. In contrast, rule (3) is more evolved and unique, since it enables a freely vibrating top plate. To confirm the the design rules, the traditional design is compared with the new one, through several methodological aspects. Results from the analysis are drawn from both analytical treatments and acoustical measurements. A listening test was also conducted and the results of this test support the assumption of an increase in loudness for the new kantele design. More specifically, on the average loud plucks of the modified design are perceived as 3 dB louder than in the traditional design. Furthermore, on certain strings the loud plucks are perceived as 6 dB louder. The proposed design ideas can also be applied to other string instruments.