मनोजवम् मारुततुल्यवेगम् जितेन्द्रियम् बुद्धिमताम् वरिष्ठम्। Whichever mantra you chant Hanuman Ji, retaining in your mind its meaning, chant it slowly or mentally with whole devotion. In no way chant the mantra aloud. ओम नमो हनुमते रूद्रावताराय सर्वशत्रुसंहारणाय यत्पूजितं मया देव! परिपूर्ण तदस्तु मे You will be the protector of saints https://zeedirectory.com/listings13210978/the-basic-principles-of-hanuman-mantra