An Acoustical Study of Individual Voices in Choral Blend

The purpose of this study was to investigate the phenomenon of choral blend by identifying spectral differences between vocal sounds produced in solo singing and in unison ensemble singing aimed at achieving optimum blend. Individual voices were recorded in isolation by having singers blend with the sustained tones of a prerecorded ensemble heard through earphones along with the singer's own voice. Recordings of the same singers producing corresponding sounds in the style of their solo singing provided pairs of sounds representing both modes of performance. In contrast to solo singing, those sounds produced in blend tended to have slightly stronger fundamental frequencies in combination with fewer and weaker upper partials, and also slightly stronger first formants in combination with weaker second and third formants. The results may explain in part how certain commonly used choral techniques take advantage of particular traits of the aural perception mechanism to produce ensemble blend.