Jump to content
Sign in to follow this  
  • entries
    32
  • comments
    29
  • views
    996

Physics of Intervals in Music

Sign in to follow this  
nathanstack15

127 views

As a saxophone player, I have always wondered how exactly sound waves work and why some notes sound good together while others don't. For example, when notes that are a half step apart are played simultaneously, "wobbles" are produced. If two sound waves interfere when they have frequencies that are not identical but very close, there is a resulting modulation in amplitude. When the waves interfere constructively, we say that there is a beat. The number of beats per second is known as the beat frequency, which is simply the absolute value of the difference in the frequencies of the two pitches. From a music theory standpoint, intervals can be referred to as consonances or dissonances. Consonances occur when tones of different frequencies are played simultaneously and sound pleasing together. Dissonances occur when tones of different frequencies are played simultaneously and sound displeasing together. According to a lecture by Professor Steven Errede from the University of Illinois, the Greek scholar Pythagoras studied consonance and dissonance using a device known as a monochord, a one stringed instrument with a movable bridge, which divides, "the string of length L into two segments, x and L–x. Thus, the two string segments can have any desired ratio, R = x/(L–x). When the monochord is played, both string segments vibrate simultaneously. Since the two segments of the string have a common tension, T, and the mass per unit length, mu = M/L is the same on both sides of the string, then the speed of propagation of waves on each of the two segments of the string is the same..." Basically, the ratio of the lengths of the two string segments is also the ratio of the two frequencies. Consonance occurs when the lengths of the string segments are in unique integer ratios. To learn more about the physics of consonances and dissonances, read his lecture here: https://courses.physics.illinois.edu/phys406/lecture_notes/p406pom_lecture_notes/p406pom_lect8.pdf.

Sign in to follow this  


0 Comments


Recommended Comments

There are no comments to display.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Terms of Use

The pages of APlusPhysics.com, Physics in Action podcasts, and other online media at this site are made available as a service to physics students, instructors, and others. Their use is encouraged and is free of charge. Teachers who wish to use materials either in a classroom demonstration format or as part of an interactive activity/lesson are granted permission (and encouraged) to do so. Linking to information on this site is allowed and encouraged, but content from APlusPhysics may not be made available elsewhere on the Internet without the author's written permission.

Copyright Notice

APlusPhysics.com, Silly Beagle Productions and Physics In Action materials are copyright protected and the author restricts their use to online usage through a live internet connection. Any downloading of files to other storage devices (hard drives, web servers, school servers, CDs, etc.) with the exception of Physics In Action podcast episodes is prohibited. The use of images, text and animations in other projects (including non-profit endeavors) is also prohibited. Requests for permission to use such material on other projects may be submitted in writing to info@aplusphysics.com. Licensing of the content of APlusPhysics.com for other uses may be considered in the future.

×