Re: "I've run the hearing test 3 times today on my new Air Pods 2 Pro.
Keeps saying unable to complete test due to background noise or something."
Wondering if Apple Support's online article (link below) may be helpful in finding success.
If you haven't seen it already: See:Take a Hearing Test with AirPods Pro 2 - Apple Support
There's also a video from Apple Support:
https://www.youtube.com/watch?v=Q5noO6dnGBs
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Re: "The room is very quiet. Is this hearing test just BS? Or does it actually work as intended and I'm doing something wrong?"
It's unlikely you are doing anything "wrong".
If some detail is being overlooked, the video above may help set things right. Seems a great many others have taken the test successfully, although some have had a difficulty of some sort to overcome. Eg: Regular sounds we no longer notice, like a plane flying overhead, may intrude, even though the room is quiet (Have even heard of people finally taking a test in a wardrobe with the door closed in order to achieve success.)
Checking with the EarTip Fit Test may be helpful:
See how to: Choose your AirPods Pro ear tips and use the Ear Tip Fit Test - Apple Support
Eg: says:
"Your ear tips should make a good seal with your ear canal.
When the fit is right, you experience better noise cancellation, and music has a rich bass sound".
and
"You can use the Ear Tip Fit Test if you're not sure that you're getting the best possible sound quality and noise cancellation. Choose a comfortable fit with a good seal."