2, this thing has nothing to do with whether it is good for the ear. Wearing headphones is good for your ears only when the environmental noise is particularly loud, such as factories, airports, battlefields and rocket launching sites. Wearing headphones was a protective measure for your hearing at that time.
3. Sony's noise reduction effect can only be said to be average. Bose is good in the field of noise reduction and has a large number of related patents. Of course, the actual effect is not as magical as advertised. Active noise reduction is mainly aimed at the regular low-frequency noise in environmental noise. However, if you use active noise reduction headphones for the first time, especially in an environment that is not particularly super, you can still feel that active noise reduction is on and it is quiet around.