ll of the instrument. It is
all a matter of resonance. This is well illustrated by a simple
experiment with a tuning fork and a spherical resonator reinforcing the
tone of the fork.

When the fork is struck, the ear hears the sound issuing from the
resonator, not that coming direct from the fork. This is brought out
distinctly by placing the fork at a little distance from the resonator.
The listener can then definitely locate the source of the sound which
impresses the ear. Under these circumstances the sound coming from the
resonator is found to be many times more powerful than that coming
direct from the tuning fork. If left to its own judgment the ear takes
the resonator to be the original source of the sound.

In the voice the exciting cause of the air vibrations is located at the
back of the resonator,--the mouth-pharynx cavity. The sound waves in
this case can issue only from the front of the resonator,--the singer's
mouth. No matter how the voice is produced, correctly or badly, this
acoustic principle must apply.

Why then does not the incorrectly used voice impress the hearer as
issuing directly from the mouth, the same as the correctly produced
tone? This is purely a matter of sympathetic sensations of throat
tightness, awakened by the faulty tone. Every wrongly used voice arouses
in the listener sympathetic sensations of throat contraction. This
impression of throat, noted by the hearer, consists of muscular, not of
strictly auditory sensations.

As a statement of scientific fact, the forward-tone precept is
erroneous. It does not describe scientifically the difference between
correct and incorrect tone-production. Correctly sung tones are not
produced at the lips. Every vocal tone, good or bad, is produced by the
motion of the vocal cords and reinforced by the resonance of the
mouth-pharynx cavity. Only when considered as an empirical description
is the forward-tone precept of value. In this sense the precept
describes accurately the difference in the impressions made on the
hearer by correct and incorrect singing. A badly produced tone seems to
be caught in the singer's throat; the correctly used voice is free from
this fault, and is therefore heard to issue directly from the singer's
mouth.

This marked difference between correct and incorrect tone throws a
valuable light on the meaning of the correct vocal action. Every badly
used voice gives the impression of wrong or unnecessary tightness,
stiffe