sūta uvāca
samāhitātmano brahman
brahmaṇaḥ parameṣṭhinaḥ
hṛdy ākāśād abhūn nādo
vṛtti-rodhād vibhāvyate
sūtaḥ uvāca - Sūta Gosvāmī said; samāhita-ātmanaḥ - whose mind was perfectly fixed; brahman - O brāhmaṇa (Śaunaka); brahmaṇaḥ - of Lord Brahmā; parame-sthinaḥ - the most elevated of living beings; hṛdi - within the heart; ākāśāt - from out of the sky; abhūt - arose; nādaḥ - the transcendental subtle sound; vṛtti-rodhāt - by stopping the functioning (of the ears); vibhāvyate - is perceived.
Because Śrīmad-Bhāgavatam is the supreme Vedic literature, the sages headed by Śaunaka desired to trace out its source.