Listen to Solfeggio Frequency (639Hz) Optimistic Resilience online. Solfeggio Frequency (639Hz) Optimistic Resilience is an Instrumental language song and is sung by Namastouf. Solfeggio Frequency (639Hz) Optimistic Resilience, from the album Solfeggio Frequencies Meditative Exploration, was released in the year 2024. The duration of the song is 1:00:00. Download Instrumental songs online from JioSaavn.