Should Basmalah be recited loudly or secretly?

Q 1: Should Basmalah (saying, "Bismillah Al-Rahman, Al-Rahim [In the Name of Allah, the Most Gracious, the Most Merciful]") be recited in Al-Fatihah (the opening Surah) subvocally or loudly?

A: According to the most correct opinion of scholars, it should be recited subvocally before Al-Fatihah in every Rak`ah (unit of Prayer).