English to Portuguese Tech/Engineering Electronics / Elect Eng fones

Open or closed back[edit]
Both circumaural and supra-aural headphones can be further differentiated by the type of earcups:
Open-back headphones have the back of the earcups open. This leaks more sound out of the headphone and also lets more ambient sounds into the headphone, but gives a more natural or speaker-like sound and more spacious "soundscape" - the perception of distance from the source.
Closed-back (or sealed) styles have the back of the earcups closed. Depending on the model they may block 8-32db of ambient noise, but have a smaller soundscape, giving the wearer a perception that the sound is coming from within their head.[11] One reason for this is that there are sounds reflected back towards the ear