Indeed, seeking knowledge is a key to gaining Allah’s pleasure both in this world and in the Hereafter. Mu`adh ibn Jabal (may Allah be pleased with him) said, “Seek knowledge, for seeking it for the sake of Allah is a sign of being conscious of Allah; acquiring it is an act of worship; studying it is a glorification (of Allah); and searching for it is (a kind of) jihad (striving in Allah’s cause) …”
Here, we would like to stress that there is nothing wrong with you deleting the audio material containing the Qur’an because it is clear from your question that you don’t intend to undermine the Glorious Qur’an by doing so. Thus, as long as your intention is pure, there is nothing wrong. On the authority of `Umar ibn Al-Khattab: I heard the Messenger of Allah (peace and blessings be upon him) saying: “Actions are but by intentions and every one shall have but that which he intended…” (Al-Bukhari and Muslim).
Dr. Sano Koutoub Moustapha, Professor of Jurisprudence and Its Principles at the International Islamic University, Malaysia, states the following: “Indeed, Islam calls upon Muslims to acquire knowledge and revive their thinking from time to time. There is no harm or prohibition in deleting the audio content which contains Qur’anic verses for the sake of learning more and getting new knowledge.
Surely, you don’t intend by deleting such material to undermine the Glorious Qur’an; therefore, it is not a sin to do so. May Allah bless you with more knowledge and piety (taqwa).