Listen to Zen Serenity (Music to Sleep Soundly) online. Zen Serenity (Music to Sleep Soundly) is an Unknown language song and is sung by Relaxation Music System. Zen Serenity (Music to Sleep Soundly), from the album Relaxation Music Heaven: Ultimate Relaxing Songs, Delta Waves & Isochronic Tones for Brainwave Entrainment, was released in the year 2015. The duration of the song is 4:03. Download Unknown songs online from JioSaavn.