Valmiki Ramayana Sundara Kanda Sarga 48 Shloka 20
Original Shlokaस तस्य रथनिर्घोषं ज्यास्वनं कार्मुकस्य च। निशम्य हरिवीरोऽसौ संप्रहृष्टतरोऽभवत्।।5.48.20।।
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सः असौ he also, हरिवीरः leader of monkeys, तस्य his, रधनिर्घोषम् rumbling of the chariot, कार्मुकस्य of his bow, ज्यास्वनं च sound of his bow, निशम्य after hearing, संप्रहृष्टः तर: more happy, अभवत् became.
The leader of the monkey also became happier on hearing the rumbling (of the chariot) and the twang of Indrajit's bowstring.