Valmiki Ramayana Sundara Kanda Sarga 18 Shloka 2

सः he, विरात्रे at the end of the night, षडङ्गवेदविदुषाम् of those who were knowledgeable of Vedas and its six auxillary branches of sciences, क्रतुप्रवरयाजिनाम् those who were experts in performing exalted sacrificial ceremonies, ब्रह्मरक्षसाम् of brahmins among demons, ब्रह्मघोषान् sounds of Vedas, शुश्राव heard.

At dawn sounds of recitation of Vedas and the six auxillary sciences, (i.e .grammar, prosody, etymology, phonetics, astronomy and the science of rituals) by the brahmins among demons wellversed in performing exalted sacrificial ceremonies were heard.