The audio begins with the distinct sound of knocking, a rhythmic rapping echoing through the air. It's a familiar sound, one that immediately paints a mental image of a hand poised in mid-air, making contact with a hard surface. The sound is sharp, clear, and precise, like the strike of a woodpecker against bark. This is the sound of a door being knocked, a knock that reverberates, a knock waiting to be answered. The knocking continues in a steady, unchanging pattern, punctuating the silence that follows each rap. It's a sound that elicits anticipation, a prelude to the arrival of someone or something. It's a universal sound, a call echoing through wood and air, waiting for a response.