Sunan an-Nasa'i, Volume 2, Book 11, Hadith 1016 (DarusSalam) ⓘ
It was narrated that Abu Bara' said: "The Messenger of Allah said: 'Make your voices beautiful when you recite Quran.'"
أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ طَلْحَةَ بْنِ مُصَرِّفٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْسَجَةَ، عَنِ الْبَرَاءِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " زَيِّنُوا الْقُرْآنَ بِأَصْوَاتِكُمْ " .
also referenced under: Hadith 1015 (Reference) & Book 11, Hadith 140 (In-Book)