As a pedantic chemist, it’s lithium that has an atomic number of three. Beryllium has an atomic number of four. Oh, and if you are mentioning mass, you should use the mass number not atomic number, which in this case is 9!
I didn't read the whole review as I'm not really interested in this type of product, but I thought the conclusion was a very well balanced piece of reviewing! Then I read some more and now I want to have a listen to a pair :-D
Intrigued by these. I’ve come to realise wireless headphones enable me to listen to music far more than speakers ever will. Pretty happy with my B&W PX7, and I’m not sure these would be worth 4x the cost? Probably not. But cool nonetheless.