Is it true that the Hanafis declared someone who enjoys the sound of singing and musical instruments to be a disbeliever?

The Hanafis did not declare the one who enjoys the sound of music and musical instruments to be an infidel. The circulated saying: "Listening to amusements is a sin, sitting through them is فسق (immorality), and enjoying them is disbelief" has no origin. The Hanafis interpreted the word "disbelief" in it with three interpretations: either it is a disbelief in blessings, or it is for emphasis and severity, or it is for whoever deems it permissible. They cited texts, among them the saying of Al-Haskafi in Al-Radd Al-Mukhtar and Bariqat Mahmudiyyah. And enjoying a sin does not necessitate deeming it permissible.