Spectral characteristics of three styles of Croatian folk singing

This paper examines the differences between three Croatian folk singing styles, namely klapa, ojkanje, and tarankanje. In order to factor out singer-specific properties, each of the styles was performed by the same 12 professional male singers. The 36 performances were analyzed with a long-term average spectrum (LTAS) method from which direct effects of the pitch distribution were removed. After factoring out each singer's average, the 36 pitch-corrected LTAS contours were reduced to a two-dimensional representation in two ways: (1) a principal-component analysis and (2) a graphical plot of spectral slope versus speaker's formant strength. Both ways clearly separate the three styles. The spectrum of the klapa style turns out to be similar to that of speech. The ojkanje style is extremely loud and shows two spectral peaks: a sharp one tuned at twice the fundamental frequency and appropriate for long-distance communication on mountain slopes, and a broad one around 3.5 kHz, reminiscent of a speaker's formant. The tarankanje style has a very flat spectrum implemented by vocal pressedness and nasality, which is appropriate for blending into or imitating the timbral characteristics of the sopile folk instrument.