Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
Physics 212 Lecture: "Longititudinal Standing Waves and Timbre."
Feb 13, 1998
- Sound waves are longitudinal: the displacement of air molecules
is parallel to the direction of the wave
- Some musical instruments create standing sound waves within
an air-filled tube
- Standing waves will occur if sound waves interfere constructively
with each other as the bounce back and forth from one
end of the tube to the other
- Tubes open at both ends, and those open at one end, have different
conditions under which standing waves can form
- In each case, there is a family of related standing waves:
the lowest in frequency is the fundamental, and those which
are higher multiples are called harmonics
- A real instrument produces a complex waveform, which consists
of a fundamental wave plus small amounts of some harmonics.
Each instrument has a different mix of harmonics, so it
yields a unique timbre.
This lecture discusses material in Chapter 17 of Cutnell and Johnson.
Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
