Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both), concerning this saying of Allah Almighty, 'And do not recite your prayer too loudly, nor too quietly' [Surah al-Isra: 110], says: When a man made supplication in prayer, he would raise his voice.
So it is in this narration, and it is not strong.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3010