Coroutine

void OtherFunction()
{
    StartCoroutine(PlayNotes());
}

IEnumerator void PlayNotes()
{
    for (int i = 0; i < newNotesCount; i++)
    {
        yield return new WaitForSeconds(TIME_INC);
        int n = notesToPlay[i];
        notes[n].Play();
    }
}