Sunan Abi Dawud Book 5, Hadith 79
The Prophet's (ﷺ) recitation at night was partly in a loud voice and partly in a low voice.
Abu Dawud said: The name of Abu Khalid al-Walibi is Hurmuz.
The Prophet's (ﷺ) recitation was loud enough for one who was in the inner chamber to hear it when he was in the house.
The Prophet (ﷺ) went out at night and found AbuBakr praying in a low voice, and he passed Umar ibn al-Khattab who was raising his voice while praying.
When they both met the Prophet (ﷺ) together, the Prophet (ﷺ) said: I passed by you, AbuBakr, when you were praying in a low voice. He replied: I made Him hear with Whom I was holding intimate converse, Messenger of Allah. He (the Prophet) said to Umar: I passed by you when you were praying in a loud voice. He replied: Messenger of Allah, I was awakening the drowsy and driving away the Devil.
Al-Hasan added in his version: The Prophet (ﷺ) said: Raise your voice a little, AbuBakr, and he said to Umar: Lower your voice a little.