As the audio opens, the steady, intense hum of a loud ventilation fan fills the space. The sound is consistent, much like a continuous drone, indicative of the power of the fan. It's noisy - not in an irritating way, but in a way that's palpable, a testament to its hard work in circulating air. The whirring and buzzing of the ventilation fan are audible, echoing the fan's mechanical operations. The sound reverberates, bouncing off the surroundings, exhibiting the vast reach of the fan's ventilation process. The audio is a raw representation of a ventilation fan in action, highlighting the fan's effectiveness despite its noisiness.