The audio starts with a resounding, deep, metallic noise that reverberates in the air. It's a heavy sound, the kind that you can feel in your bones, reminiscent of a large, weighty door being forcefully shut or opened. It's a rough, grinding noise, like metal on metal, suggesting the presence of a rusty hinge or bolt. The loudness and intensity of the sound indicate that the door, if that's indeed the source, is enormous, possibly wrought from solid, aged metal. The metallic echo lingers for a while before it slowly fades into silence.