Category MA P21 Harmony and Discord

Abstract Harmony and Discord

Pelham C. Barron

Huron High School, Ann Arbor, Michigan



This project compared irrational ratios of sound wave frequencies with

rational ratios of sound wave frequencies. These were generated by

plucking taut strings of specific lengths and subjectively rating them as

harmonious or discordant. Drawings of the frequency ratios were

produced by a harmonograph and a computer model. The closer the

irrational ratio was to a rational ratio, the more organized and less chaotic

the drawing was. Ratios very close to rational ratios almost sounded

pretty good while those that were way off sounded very dissonant or out

of tune. Frequencies in rational number ratios align themselves periodically

caused the rational sounds and drawings to look neat. The irrational ratio

drawing and sounds never completely aligned making the drawing and

sound very chaotic.



Bibliography Harmonograph, A visual Guide to the Mathematics of Music

by Anthony Ashton 2003



The World of Mathematics– chapter ‘The Mathematics of Music’

by James Roy Newman 2000



Temperament: The Idea That Solved Music's Greatest Riddle

by Isacoff, Stuart M. 2001



Paper:

On Regulation and Hidden Harmony William S. Huff 2008
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