Simple experiments with the tuning-fork have shown that while the volume of sound it gives forth is due in part to the amplitude of its vibrations, its loudness is _chiefly_ due to the character of the _resonance_ provided for it.
The larger the resonance chamber the greater is its reinforcing capacity.

The largest air chamber in the body is the chest, which serves not only as a wind-chest, but as a resonance chamber.

The necessity for chest expansion, therefore, is not, as generally supposed, merely for air, but to increase its size as a resonance chamber.
In view of the laws of tone, how great is the common error of speaking of the larynx as if it alone were the vocal organ, when the principal vibrations are _above_ the vocal cords in the chambers of _resonance_! Since the musical value, the beauty of tone, as well as its volume, comes only from right use of the resonator, our principal business must be the acquiring control of the vibratory air current _above the larynx_.

The acquirement of this control involves the proper focusing or placing of the tone, with the free uncramped use of all the vocal organs; power will then take care of itself..