The Cambiata Concept was one of the first methodologies used in the United States to teach boys to sing during the adolescent voice change. Previous practices of choir masters was to rest the voice during this time. They felt that by having boys sing during the voice change was damaging to the voice and would ruin the ability to sing after the mutation. Irvin Cooper, founder of the Cambiata Concept, discovered that boys were capable of singing during the voice change, and devised a method for boys to continue to sing during this tumultuous time. Cooper discovered, through empirical evidence, the gradual progression of the voice change. He states that boys' voices only "crack" when expected to sing music that is outside of the physical range of the voice. The Cambiata Concept encourages teachers to use music that is appropriate to the ranges of the voice change, and by so doing will avoid such instances from happening. Cooper and the Cambiata Concept were influential in concurrent and later music educators in the field of voice change research such as John Cooksey, Don Collins, and Lynne Gackle. He is an influential music educator in the United States who did not accept longstanding tradition. His methodology allowed countless boys a chance at music that previously would have been denied.