The signature sound of four unaccompanied male voices singing in harmony has been the roots of the style, but modernizers want new blood and fresh ideas. Supporters of the traditional style are also known as ‘kibbers,’ for the slogan ‘Keep It Barbershop.’ The traditionalists question the use of modern songs in barbershop harmonizing. Some say the chord structures don’t lend themselves to harmonizing because they are based on the blues, not classical sounds.”