I had a chance to listen to video. I can't tell if it's a part vibrating or a fan (either rubbing on something, out-of-balance, or bad bearings). There are various fans and usually one inside the power-supply itself.
Hello there, I have a brand new Alienware Aurora R15 desktop with a RTX 4090. It has recently started having this vibration sound that I cant seem to find and diagnose myself. I have checked all the fans (nothing is touching). Also unplugged each one to see if it went away. I have checked the GPU and also unplugged to see if it was that. I have checked all cable connections, cables themselves, plastic clips, opened both side panels to take a look, checked all the screws I could find and tighten them down. I have looked under the top cover, checked power supply. I am just completely stumped. I'm about to open up a support ticket. The sound is quite loud and annoying. Only thing I can think of is something is causing a vibration when the machine is on and its behind areas I don't feel comfortable exploring. Here's a video from a link with the sound. I posted in Reddit and another owner has recently noticed the same issue. If any suggestions come about, please let me know. For this expensive machine it shouldn't sound like its going to fall apart. Thanks 
Aurora R15, vibration sound