I have those headphones and like them. I have been in the process , myself , of learning about headphones - the different styles and how they are used. There are open back headphones, and closed back headphones. When you are using headphones and other people are present and you don't want to disturb them you would want closed back headphones. They prevent sound from leaking out , and also help to keep sound from the environment from intruding on your listening. Open back , you can hear the sounds from your environment and some sound will escape into the environment. A google search will tell you all you want to know about closed/open back. The AKG K240 are considered semi- open back.