Abdullah bin Abi Qays (may Allah have mercy on him) says: I asked Aishah (may Allah be pleased with her) about the witr of the Messenger of Allah (peace and blessings be upon him), and she said: Sometimes the Prophet (peace and blessings be upon him) (prayed it) in the early part of the night and sometimes in the last part of the night. I said: In the prayer, did the Prophet (peace and blessings be upon him) recite aloud or silently? She said: He did both, that is, sometimes silently and sometimes aloud; and sometimes he (peace and blessings be upon him) took a ritual bath (ghusl), and sometimes he performed ablution and went to sleep.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4836