The music of "The Ancient Solfeggio Frequencies, Tuned With Vocal Harmonics" is the only using vocal overtones ( vocal harmonics and deep voice tones) and not synthetic tones. The release of this music was inspired by the positive comments and feedbacks of so many people who expressed their love and support during this sonic journey . Gianni Bardaro, author of the album and videos as well, is mostly known as composer/saxophonist (Universal Music Artist) but he is also a certified sound therapist. NOTE: Vocal Harmonics are perfectly safe as they are non addictive and non abusive. However they may not be suitable for people with epilepsy or other seizure sufferers and should therefore be avoided. Anyone who uses a pacemaker or is taking medication (legal or otherwise), should only use brainwave entrainment recordings with medical advice.