Comparison of Heard and Imagined Blends of Instrumental Dyads

Abstract

Timbral blend is fundamental in various musical activities for shaping sounds and musical intentions. Previous studies on blend perception have mostly focused on sounding blends, neglecting imagined blend made possible by inner hearing where sounds are imagined in the mind. Experiment 1 investigated how imagined blend compares to the perception of heard blend and whether musical background has an effect. Two groups of participants (musicians and nonmusicians; N = 31 per group) were presented with pairs of short instrument sounds in unison from 14 different instruments in two different experimental conditions. In the first condition, paired sounds were played sequentially, and participants were instructed to imagine them being played simultaneously and to rate their degree of blend. In the second condition, pairs of instrument sounds were played simultaneously, and participants were asked to rate the perceived degree of blend. Results showed significant interaction effects among the instrument pairs, presentation conditions, and musical backgrounds. Acoustic modeling and multidimensional scaling of blend ratings showed both varying and invariant roles of different acoustic features between the two types of blend perception. Imagining blend appears to be more sensitive to differences in brightness and richness of the high partial content between the blending sounds. Experiment 2 with 48 participants was conducted on the perception of dissimilarity between instruments, using the same stimuli as the previous experiment. Results from this experiment provided evidence that evaluating imagined blends is strongly informed by judging the dissimilarity of blending instruments. In practice, how the two types of blends differ is a result of complex interactions involving the specificity of blending instruments and listeners’ musical backgrounds.