Valmiki Ramayana Aranya Kanda Sarga 45 Shloka 16

तस्य his, स्वरः voice, न not, व्यक्तम् it is clear, केन चित् by some one, मायया deceptively, कृतः is made, सा that, तस्य रक्षसः of that demon, गन्धर्वनगरप्रख्या like the city of the gandharvas, माया illusion.

Surely it is not his voice. It is contrived by some one's illusory power. It is the illusion created by that demon, like the city of the gandharvas. (which does not exist.)