As to whether these troublesome spots were due to the nature of the voice itself or to technical deficiencies, Celletti says: "Even if, when passing from one register to another, Callas produced an unpleasant sound, the technique she used for these transitions was perfect." Musicologist and critic adds, "Callas's 'faults' were in the voice and not in the singer; they are so to speak, faults of departure but not of arrival. This is precisely Celletti's distinction between the natural quality of the voice and the technique." In 2005, Ewa Podleś said of Callas, "Maybe she had three voices, maybe she had three ranges, I don't know—I am a professional singer. Nothing disturbed me, nothing! I bought everything that she offered me. Why? Because all of her voices, her registers, she used how they should be used—just to tell us something!"