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Blood Bars
Matt Hoffman GS
Department of Computer Science
A leading psychophysical explanation of the phenomenon of sensory dissonance in music and sound claims that dissonance is caused by the ear’s difficulty in discriminating between two partial harmonics whose frequencies lie too closely together. When two such frequencies lie within what has been termed a critical bandwidth, sensory dissonance is experienced. This experience is maximized when the two frequencies are separated by roughly 30-40 percent of a critical bandwidth, and disappears when the two frequencies are equal or separated by more than a critical bandwidth. As an undergraduate at Columbia, I produced a tool capable of analyzing, visualizing, and artificially altering the dissonance content of arbitrary sound files. This image was captured from its interface, which displays a spectrogram with each partial harmonic present in the sound colored according to the amount of dissonance it contributes to the sound. (Blue represents minimal dissonance, with green, yellow, and red each representing successively stronger contributions of dissonance.) This image is an analysis of a clip towards the beginning of the Slayer song “Blood Red.” My dissonance reduction algorithm has been applied in five thin vertical bars to those sections of the clip preceding and following note onsets. This shows the dramatic large-scale contrasts that can exist between areas of high and low dissonance.