This was re-sampled from the original by pempi. The sound was cleaned from any noise (unfortunately the electrical hum disappeared) and edited in order to make it longer. Added some variations, so it doesn't sound too looped. The stereo channels of the original soundtrack were mixed in a single mono channel.
Sorry! I interpreted it wrong, I thought you said that I cleaned too much the noise. But indeed I did. Even despite using the minimum setting and despite attenuating the noise sample first, I cleaned it too much. That's why the aluminium effect: the cleaning operation was excessive. Anyway, the original sound had too much noise, and that's what you will get when you try to clean it. Strong clean it will make it worse.
Indeed. I used the minimum setting on Audacity to clean the noise. I even attenuated the noise at the zone where I took the noise sample. However, it is very difficult. The noise reduction tool doesn't have a fine setting. That happened because the original sample had too much noise.