Source
Filter Theory by Gunnar
Fant 1960
Án·½Âoªi²z½×
In acoustic
phonetics¡Bsource
refers to the wave
form of the
vibrating larynx.
Its spectrum is rich
in harmonics¡Bwhich
gradually decrease
in amplitude as
their frequency
increases. The
various resonance
chambers of the
vocal
tract¡Bespecially the
movements of the
tongue and lips¡Bthen
act on the laryngeal
source in the manner
of a
filter¡Breinforcing
certain harmoncis
relative to others.
The combination of
these two elements
is known as the
source-filter model
of vowel production.
The complex waves
produced during
voiced periods of
speech depend on two
things:
- the waves
produced by the
vocal cord
vibrations (the
source)¡Band
- the way
those waves are
modified by the
higher parts of
the vocal tract
(the
filter).
An important
feature of the
source are its
harmonics. One of
the most important
ideas in
understanding the
filter is resonance.
http://www.columbia.edu/itc/psychology/rmk/T2/sf_theory.html