Zooming out further, we see a sinusoid with a
low-frequency sinusoidal amplitude envelope.
Figure 3:
Sinusoids at 18 and 22 Hz.
![\scalebox{0.8}{\includegraphics{eps/sumsinD.eps}}](img10.png) |
An audio version of this note (with frequencies at 218 and 222
Hz) can be heard
here.
The result is a sound that comes in and out of prominance,
usually described as beating.
Why does this effect occur?
``Music 171: Amplitude Modulation''
by Tamara Smyth,
Department of Music, University of California, San Diego (UCSD).
Download PDF version (am171.pdf)
Download compressed PostScript version (am171.ps.gz)
Download PDF `4 up' version (am171_4up.pdf)
Download compressed PostScript `4 up' version (am171_4up.ps.gz)
Copyright © 2019-11-05 by Tamara Smyth.
Please email errata, comments, and suggestions to Tamara Smyth<trsmyth@ucsd.edu>