Timbral determinants of the Karadeniz kemenche: a multimodal analysis of material and geometric influences

The Karadeniz kemenche, a traditional bowed lute from Turkey’s Black Sea region, exhibits distinct structural adaptations that shape its acoustic signature across musical repertoires. This study integrates experimental modal analysis, cluster statistics, and regression modelling to investigate how material and geometric parameters relate to the instrument’s sound production. Through testing of 18 regionally representative samples, a binary classification was identified: bass-oriented instruments ( n = 11) predominantly use ivy/plum with thicker soundboards (0.31 ± 0.02 cm), while treble-oriented designs ( n = 7) employ dense mulberry with thinner soundboards (0.25 ± 0.01 cm). Higher Mode 7 frequencies (867 ± 18 Hz, associated with neck-scroll vibrations) correlate with greater high-frequency spectral content in treble-oriented instruments. Cluster analysis confirms this division (Gap statistic = 0.82), with spectral energy variance explaining 79% of group differences (PERMANOVA, p = 0.002). Regression models quantify key predictors, revealing fingerboard/nut thickness as the most influential variable (13.22% effect) and validating material choices through large effect sizes ( η 2 = 0.58 for woods). Mode 1 frequency (∼60 Hz) serves as a structural indicator reflecting body stiffness, though the two-octave gap from playing frequencies (200–330 Hz) precludes direct resonant enhancement. The findings reveal correlations between regional music traditions and instrument construction parameters. Methodologically, this work advances heritage instrument analysis by combining vibrational testing with predictive modelling, offering a transferable framework for studying material-structure-sound relationships in other folk instruments. For luthiers, the results provide evidence-based design guidelines, while acousticians gain insights into how craftsmanship traditions correlate with modal energy distribution. Two transitional samples with hybrid properties suggest a design continuum worthy of further exploration.