Kalman Felberbaum (30 July 1923
– 21 December 2018) was an operatic bass singer who enjoyed an international career using the professional/stage name Carlos Feller.
Of Polish descent, he grew up in Argentina, and made a career in Germany, based for decades at the Cologne Opera.
He specialized in comedic supporting roles, especially bad-guys and strange, quirky characters.
His signature role was Don Alfonso in Mozart's Così fan tutte.