The first in the industry! Xiaomi MIX Flip is the first to realize the closed-cover earpiece call

 almost all small foldable phones on the market can only use the hands-free mode to make and receive calls when the cover is closed, and the privacy of communication cannot be guaranteed.

Xiaomi MIX Flip starts with the signal and the playback and reception of sounds, and for the first time realizes calls with the earpiece closed, solving the problem that the small foldable phone can only be used for hands-free listening when the cover is closed.

Today, Xiaomi’s official Weibo account released a post, revealing the details of the technical implementation behind it.

In terms of signal, the antenna layout and performance of small foldable phones on the market are comparable to those of straight-screen phones when unfolded; but when closed, the antennas will overlap and interfere with each other, and the available radiation area is reduced due to hand-grip obstruction, so the probability of “grip death” is much greater than in the unfolded state.

However, Xiaomi MIX Flip’s four low-frequency antennas ensure smooth communication in weak signal environments such as the countryside.

The mid-high frequency “hero antenna” designed on the top of the machine works with the Xiaomi Pengpai T1 signal enhancement chip to bring better signal performance.

The network subsystem of Xiaomi HyperOS can select the best antenna based on the user’s current holding posture, and optimize the network cell based on the user’s daily network usage habits . The coordination of software and hardware ensures that the signal continues to flow in the closed state.

As for the earpiece, because the internal space of the small folding phone is extremely limited, it can often only meet the needs of the unfolded state. An earpiece is designed on the inner screen side. When closed, the earpiece is blocked on the inside, and the call sound can only be played through the bottom speaker.

Xiaomi MIX Flip is the first to apply dual-diaphragm dipole speakers to small folding phones, equipping one sound unit with a set of diaphragms on the inner and outer screens, allowing calls to be made with the earpiece open or closed.

Xiaomi MIX Flip also uses the physical property of “opposite phase cancellation” of the dipole speaker system to prevent call voice from spreading outward regardless of the open or closed state, thus ensuring the privacy of the call.

In addition, when the small folding mobile phones on the market are closed, the two sets of mics change from being arranged up and down to being arranged on the same side, which affects the reception and noise reduction effects, and thus affects the sound quality of calls.

Xiaomi MIX Flip also adds an independent mic in the hinge area, which echoes the independent earpiece on the top, and re-forms the microphone combination with the top mic to ensure the clarity of the reception.

Through the above technical and structural innovations, Xiaomi MIX Flip finally realized the use of the handset with the cover closed.