Authors: Henri Penttinen (*,**) and Esa Lilja(***)

*: Helsinki University of Technology (TKK), Department of Signal Processing and Acoustics

**: Stanford University, Center for Computer Research in Music and Acoustics (CCRMA)

***: Helsinki Univeristy, Institute For Art Research

Abstract

The power chord, a distorted interval of the perfect fifth, is one of the major musical tools in pop and rock music. We approach the effect guitar distortion has on specific chords from the perspectives of music theory and musical acoustics. The spectrum of a distorted guitar chord shows that the actual sounding structure of a distorted chord is more complex than the notes played would imply. Our formulation shows, how the position of the additional distortion frequency components depend on the ratio of the interval. The distortion components are the main reason for why the power chord has been so prominent in heavily distorted guitar music. Our results indicate that music theory and musical acoustics are not up to date regarding distorted chords.