Is audibly invoking blessings upon the Prophet — may God's prayers and peace be upon him — contrary to the Sunnah?

The ruling on raising one's voice with prayers upon the Prophet (peace be upon him) was previously detailed in a fatwa. The statement of the author of "Islah al-Masajid" does not merely refer to raising the voice, but rather to certain innovations practiced by some worshippers after finishing the prayer, such as the muezzin raising his voice with "ameen" and supplication, or the congregants raising their voices with the "Kamaliya Prayer" upon the Prophet (peace be upon him) after concluding the prayer with taslim. This is contrary to the Sunnah, as the Sunnah dictates engaging in the prescribed remembrances silently after the obligatory prayer, with each worshipper doing so for themselves. Similarly, lowering one's voice is part of the etiquette of supplication, as Allah Almighty says: "Invoke your Lord humbly and privately." (Quran 7:55)