They get a soul voice.

NPR: Leela James: New Soul From An Old Soul

DeRose also has a secret weapon: a voice that seems to expose his very soul.

NPR: Peasant: 'Fine is Fine'

Her name is synonymous with Chicago blues, and her voice was growling, thunderous and full of soul.

NPR: Blues Queen Koko Taylor Dies At 80

And therefore it's that voice from the side, the voice that speaks not to party politics and immediate interest, but to the innermost soul of the human within us, the divine within us, which actually succeeds because it has no power at all.

BBC: NEWS | In Depth | Blending politics and religion