Closed-back (or sealed) styles have the back of the earcups closed. They usually block some of the ambient noise, but have a smaller soundstage, giving the wearer a perception that the sound is coming from within their head. Closed-back headphones tend to be able to produce stronger low frequencies than open-back headphones.
Semi-open headphones, have a design that can be considered as a compromise between open-back headphones and closed-back headphones. This may imply that the result combines all the positive properties of both designs. Some believe the term "semi-open" is purely there for marketing purposes. There is no exact definition for the term semi-open headphone. Where the open-back approach has hardly any measure to block sound at the outer side of the diaphragm and the closed-back approach really has a closed chamber at the outer side of the diaphragm, a semi-open headphone can have a chamber to partially block sound while letting some sound through via openings or vents.
After our time with the Sine, the EL-8 Ti’s Cipher Lightning cable was very familiar. It’s slightly thicker, but is the same length, has the same control pod, and works with the Audeze iOS app. The biggest difference is in its connectors, a pair of 8-contact plugs that can only be inserted into the headphone one way. Though we would have preferred that the Cipher cable at least be compatible with Audeze’s other headphones, Audeze has defended the new connector by claiming that it offers technical advantages: it has lower electrical resistance, can carry more current, and enables them to add features like noise cancellation and DSP in the future. While we’re interested to see how Audeze exploits these capabilities in the future, we had to settle for testing the Lightning cable’s performance here in the present.