“Thank you for additional information on the Sound of Silence. I’ve known of the Sound of Silence, but not that there was any formal or structured practice around it. I’m wondering if Ajahn Chah or his predecessors did any teachings on this or if there are suttas related to it.” Answered by Ajahn Pasanno. [Sound of silence] [Ajahn Chah] [Sutta]
Reference: Inner Listening by Ajahn Amaro.