Praise be to Allah.
Making one’s voice beautiful when reciting Qur’aan is something that is prescribed and was enjoined by the Prophet (peace and blessings of Allaah be upon him). The Prophet (peace and blessings of Allaah be upon him) listened to the recitation of Abu Moosa al-Ash’ari and liked it, and he told him, “You have been given a melodious voice like that of Dawood.” (Muslim, Salaat al-Musaafireen, 793).
On this basis, if the imam of a mosque imitates a person who has a beautiful voice and recites beautifully in order to make his own voice and recitation of the Book of Allaah more beautiful, this is something which is prescribed for him and for others, because it moves the worshippers praying behind him, and makes them focus, listen and pay attention to the recitation. Allaah bestows His bounty on whomsoever He wills and He is the owner of great bounty.