Natyashastra
परिगीतक्रियारम्भ आरम्भ इति कीर्तितः । आतोद्यरञ्जनार्थं तु भवेदाश्रावणाविधिः ॥ १८॥
The beginning of the action of singing is called the commencement. Therefore, the method of pouring out sounds is meant to delight the ear.
english translation
parigItakriyArambha Arambha iti kIrtitaH । AtodyaraJjanArthaM tu bhavedAzrAvaNAvidhiH ॥ 18॥
hk transliteration by Sanscript