In echoes of the problem, things that need to be considered by the vocalist was: recognize the resonance cavity, strengthen the walls of the resonance, enlarging the cavity resonance. It was to bring about a weighty and brilliant sound. Know the cavity resonance, how to realize and feel that the singer's body is an echo sound, can be reached by road hum. With jaws open position, then the position open, valve lips lightly and hummed melodies as follows:
Both the chromatic melody sung over from c-cis-d-dis-e-ffis-g-gis-a-ais-b ...... and so on up and down each half barrel, measuring boundaries vocalist concerned tone.
Stiffen the walls of resonance, the effort is aimed at moving towards a bright sound. This can cause the echo can be processed perfectly. By chromatic up and down each half barrel, extended as far as the singer is concerned.
Enlarge the cavity resonance, aimed at gaining votes are weighted (thick volume). This can be done by way of singing the melody below using syllables.