In Turkey, the muezzin calls Muslims to prayer five times daily. But not all of them hit the correct notes. Now they are receiving singing lessons to help them stay in tune.Many muezzins in Istanbul deliver an impassioned call to prayer, but it is not always music to the ears. Overamplified external speakers also impact on the voice quality, making it sound tinny and distorted. Residents living near mosques often complain about the noise. Now the Mufti of Istanbul has decided to tackle the problem. The muezzins have been ordered to take classes. Any muezzin found unable to sing will have his voice replaced by a professional recording.