Do you think that ears can be damaged this way?
Yes, they absolutely can be damaged this way. Be very careful if you are doing extended practice with headphones. It's a great tool, but you have to keep the volume very low. I spent almost a whole year practicing around 2 hours a day through closed style studio headphones. I was aware that I needed to keep the volume down, but didn't always. I had some tinnitus before this, but it has gotten worse, I have constant ringing in both ears, and it is very annoying. Not debilitating (yet, cross your fingers) but it's an annoyance. I only use the headphones now when I need to, and when I do, I keep it so low I can still hear people talking around me (and my headphones are studio quality, outside noise reducing.)You said "moderate volume, of course" but you also mentioned "intensive playing through headphones". Be very careful. There is very real change for damage to youe ears. That's all I can really say. -Paul