Analysis of the timbre of Slovak folk reed aerophones using source-filter model

Abstract

Bagpipes are the only group of traditional folk reed instruments that have survived in Slovak folk culture until now. Unlike Scottish highland pipe, gaita, cornemuse etc., all the types of Slovak bagpipes use single reeds in both chanters and drones. Moreover the horns of the drones are partly closed with a plate having only a small opening for air output and sound radiation. This forms a Helmholz-like resonator - acoustic filter having a strong influence on the acoustic and aesthetic properties of the sound. The ideal of the sound timbre of these pipes is "less open" (compare to open and closed vowels in speech) and, in spite of its relatively high loudness, "less agressive" in comparison to pipes with open horns. This paper presents our approach to study the ideal of sound timbre of the Slovak bagpipe using a source-filter all-pole model. To identify resonance frequencies/formants, we applied inverse filtering technique using discrete linear prediction. Some properties of the source (reed) were studied using parameters like amplitude qutient and open quotient. The possible relations between timbre of speech sounds (vowels) and the timbre of the sound of musical instruments are discussed.