Undertone Series

With permission, I quote Jon Catler from his article Just Intonation in
Modern Music (PITCH I:1, Autumn 1986):

"There is another, sort of magical way in which the undertone series
manifests itself. Whenever two tones are sounded simultaneously, other
tones are produced in the human ear that are not actually being played.

"The difference between the frequencies of the two notes being sounded
produces a third note below the range of the first two, called a
difference tone. By playing through a _descending_ harmonic series with
two notes and keeping a "B" on top, we can see that the difference tone
line creates an _ascending_ minor scale that corresponds exactly to the
Undertone Series created earlier from mirror-imaging.

"In this way, we can see how the overtone series and the undertone series
are not separate--in fact, they are inseparable."
(Jon Catler, PITCH I:1, p. 5)

Johnny Reinhard
Director
American Festival of Microtonal Music
318 East 70th Street, Suite 5FW
New York, New York 10021 USA
(212)517-3550/fax (212) 517-5495
reinhard@idt.net
http://www.echonyc.com/~jhhl/AFMM