Musical Dissonance

When we hear a combination of two pitches, we judge the musical consonance or dissonance of the combination not solely by whether the two fundamental frequencies are within a critical band of each other but also by integrating the overall degree of interaction (or lack of interaction) among all possible pairs of harmonics from the individual tones.  If a given pair of harmonics happens to match exactly in frequency we hear no interaction at all, similar to hearing a single-frequency component.

If the frequencies of another pair of harmonics do not match but lie within a critical band of each other, interaction in the form of beating or roughness is heard. If a pair of harmonics do not match and the component frequencies are separated by more than a critical band, we again hear no interaction. Because the relative strengths of the various components can vary greatly and in a time-varying manner, the overall degree of interaction between two complex tones can be difficult to predict. Nevertheless it is precisely our overall impression of the degree of interaction that we call musical dissonance.

TOM SCARFF
1 Martello Court
Portmarnock
Dublin
Ireland.

Email: tscarff@eircom.net