Abdullah bin Abi Qays said: I asked Sayyidah Aishah (may Allah be pleased with her) how the night recitation of the Prophet (peace and blessings be upon him) was. Did he (peace and blessings be upon him) recite aloud or quietly? She said: "Sometimes aloud and sometimes quietly." I said: "All praise is for Allah, who has made latitude in the matter."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4710