Is raising one's voice above the voice of the Prophet (peace be upon him) an act of disbelief (kufr)?

Raising one's voice or speaking loudly above the Prophet's voice is not in itself disbelief, unless it indicates disdain or mockery. Allah has forbidden this to prevent the means to this evil, and warned that such leniency could lead to disbelief and the nullification of deeds. This is because failure to guard against ill-manners towards the Prophet, peace and blessings be upon him, after this prohibition, may lead the perpetrator to a great sin, or to disbelief. This is because not ceasing ill-manners accustoms the soul to persist in them, increasing ill-manners and decreasing reverence for the Messenger, until it reaches the point of disbelief. This is the meaning of His saying, the Exalted: "while you perceive not."