Devialet Gemini Review

Specifications

For the nitpickers and nerdy ones here, I’m giving the specs and technical sheets. For all the others, you can just go to the next page to see how the Gemini performs.

Internal Delay Compensation and Pressure Balance Architecture

Devialet dedicated a full white paper to its Gemini, so let me summarize it.

Usually, the higher the frequency, the more it results in a significant delay in noise reduction at the highest frequencies. This can lead to the emergence of a phase shift in the system. Added to this is the strong directivity of the higher frequencies, which are harder to cancel out than the less directive low frequencies. 

IDC involves a proprietary signal processing that precisely adjusts the noise-canceling filters by anticipating the natural limitations of an ANC system. The sound signal processing is digitally performed in the frequency domain and is the subject of a filed patent. The IDC algorithm directly affects the transfer function of the noise-canceling filter, ensuring its response is optimized to extend the noise-canceling range from sub-bass to midrange.

In addition to that, the Gemini also comes with PBA (Pressure Balance Architecture). It features a unique acoustic architecture equipped with a three-vent decompression system. Stemming from the challenge of limiting the static air compression encountered in in-ear headphones during insertion into the ear, the PBA® architecture optimizes the speaker’s low-frequency sensitivity while enhancing isolation from external noises. 

The cascading vents ensure decompression (i.e., equalizing the static pressure) by allowing the air from the ear canal to flow outward. They incorporate specific meshes that dampen acoustic propagation. The impedances selected for these meshes, along with the size of the dual rear charge cavities, achieve high passive isolation from ambient noise combined with significant low-frequency sensitivity.

Long story short; better noise canceling, less harm to the ears.

Proprietary driver and EAM

To ensure a full coverage of the whole hearable frequency range, the Devialet Gemini comes with a 10mm driver, supposedly capable to deliver exceptional sound from 5Hz up to 20kHz, like the Phantom II in fact. In addition to that, the TWS also comes with a proprietary algorithm, namely the Ear Active Matching.

The operation of the EAM algorithm can be summarized as follows:

• the earbud’s response is measured using the musical signal and the signal captured by the internal microphone.
• the measured response is tracked and used to modify a compensation filter and adjust the equalization accordingly.

The algorithm is directly computed in the Devialet Gemini microcontroller before the digital-to-analog conversion and the amplification circuit. It corrects the musical signal played by the speaker by measuring acoustic leaks several thousand times per second. The signal played by the speaker is then captured using the internal microphone (known as feedback) and compared to the initially stored signal to determine the optimal equalization to adopt in all circumstances.

All good things on paper, but let’s see how that translates in real world performance.

Sensitivity / Hiss

The Gemini aren’t hard to drive: the amplifier and DSD are directly built-in, so all you have to do is connect your source, and click play. There is no hiss whatsoever, whether you use “transparency mode”, “noise-canceling” or even “pure” mode.

Volume can reach high volumes even though it’s a TWS, so you should stay just below your comfort zone, to train your ears. This TWS always monitor the sound level outside AND inside, so it should never be harmful, but stay aware.

Full specs

• Model: Devialet Gemini
• Type : True Wireless IEM
• Chipset: home made chipset
• Driver : Proprietary large excursion transducer (unknown)
• Connectivity : Bluetooth 5.0 (AAC/SBC/apX)
• Battery Life : 20 hours (with the case) – 6h per charge
• Shell : PC-ABS (earbuds) / aluminium + TPU (case)
• Frequency response Range : 5Hz – 20kHz
• Impedance : NA
• Sensitivity : NA
• Microphone : dual beamforming mics
• Price : $179/€179

The article continues on Page four, after the click here

Page 1: About the brand, design and build quality 
Page 2: Bundle, comfort, usage
Page 3: Specifications
Page 4: Sound performances