The sound vibration of the Hare Krishna mantra, although presented in the ordinary alphabet, should not be taken as mundane or material.
Srimad bhagavatam 4.9.4,
This beautiful material world is nothing but a shadowy reflection of the reality, the kingdom of God.
Srimad Bhagavatam 1.19.13,
Material world is like a dream.
Everything in Material world is temporary.
Ignorance is the cause of sinful life, and sinful life is the cause of one’s dragging on in material existence.
Bhagavad Gita 4.31,
Material world brings pleasure and miseries.