Resumen de Inharmonic Spectra with a Rock Guitar Effects Pedal
Students in introductory physics courses encounter harmonics when they study standing waves on strings and in pipes. The Fourier spectrum, which plots amplitude against harmonic number, can describe all periodic tones imaginable. However, most sounds are aperiodic and therefore have additional spectral components. A real-world application that includes frequencies outside the harmonic series can be found in guitar pedal effects used by rock musicians. A four-minute video1 accompanying this paper includes the exotic sound of guitar playing when the guitar pedal adds inharmonic frequency components. The principle underlying the pedal effects discussed in this paper is balanced modulation. Some inharmonic spectra based on balanced modulation can easily be sketched after students have learned about timbre and Fourier spectra.
