Shaikh ’Uthaimeen, may Allaah have mercy on him, said, “It is not proper that the person praying behind an Imaam should make any of his recitation heard, not in the silent prayers or the audible ones, nor when saying Allaahu Akbar or when praising Allaah or when supplicating, because he is following and is not the one who is being followed, and because by making his voice audible he will confuse the people around him.”

At-Ta’liq ’alaa al-Muntaqaa, p. 45.