Who said "The soprano must balance power with delicacy."?

This quote is attributed to Joan Sutherland.

The soprano must balance power with delicacy. - Joan Sutherland

"The soprano must balance power with delicacy."

Joan Sutherland

Opera Soprano Australian 1926–2010

"I am just a girl who loves to sing and to share that gift with others."

"The voice is a muscle that needs to be trained and respected."

"You must always strive for perfection, but you must never believe that you can achieve it."

"Hard work is the price of success."