OPPO ENCO X2 Teardown: Coaxial Dual-Unit Technology, Cast Liquid Crystal Diaphragm

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Recently, the OPPO Enco X2 jointly tuned by Joe Hisaishi can be said to be a popular product among TWS earbuds. The headphone and Dynaudio jointly developed the second-generation coaxial dual unit of SuperDBEE, which allows the 11mm full-range dynamic driver unit and the 6mm flat four-magnetic tweeter to be coaxial, making music reproduction natural and realistic. In terms of battery life, earbuds have powerful energy in a small body, and can achieve up to 40 hours of battery life with the charging case.

We have shared with our friends about the experience of using the OPPO Enco X2 before. In terms of appearance, the handle-shaped in-ear design is adopted, the earphone handle is shortened, and the weight is reduced to 4.7g, which enhances the wearing comfort. In terms of listening sense, after the golden sense of hearing is turned on, the second-generation coaxial dual-unit of SuperDBEE is used, and the sound quality performance far exceeds the performance of earbuds at the same price. The only downside is that in multi-instrument music the earbuds can’t bring the music to the user’s ears in an orderly manner.

We also disassembled OPPO Enco Air 2, OPPO Enco Free2, OPPO Enco X, OPPO Enco W51, OPPO Enco Air, OPPO Enco W31 and OPPO Enco Free true wireless bluetooth earbuds before.


01/ OPPO ENCO X2 Unboxing

The front of the outer packaging of the OPPO Enco X2 true wireless noise cancelling earbuds. The outer packaging adopts the usual simple style of OPPO. On the left is the product series “OPPO ENCO” of earbuds, in the middle is the product display of OPPO Enco X2 earbuds, and in the lower right corner is the product name X2.

The upper right corner of the front of the outer package shows the OPPO Enco X2 jointly developed by OPPO and Dynaudio with hot silver font.

The lower left corner of the front of the outer package is the Hi-Res gold label certification, showing that the earbuds have passed the high-quality sound certification.

The back of the box shows the product features of the OPPO Enco X2. The earbuds support IP54 dust and water resistance and come with antibacterial eartips. In terms of battery life, OPPO Enco X2 supports up to 40 hours of battery life.

In terms of research and development, OPPO Enco X2 and Nordic Dynaudio jointly developed the acoustic system, and invited the hall-level master Joe Hisaishi to tune it. In terms of functions, earbud supports “Hi-Res Wireless” ultra-high-definition sound quality transmission, ultra-wideband active noise cancelling, bone conduction AI call noise cancelling, Bluetooth 5.2+ low-latency dual transmission, device dual connection and binaural recording.

The bottom label information, the product name “OPPO Enco X2 true wireless noise cancelling earphones”, supports the LHDC bluetooth protocol. Earbud model ETE01, Bluetooth version 5.2, charging case model ETE02, battery type “rechargeable lithium-ion battery”, sound unit “φ11mm dynamic unit, φ6mm flat diaphragm unit”, frequency response range “20Hz-40kHz”, charging case input voltage “5V⎓2A”.

Take out all the accessories in the box, the product list is as follows: 3 pairs of eartips (S/M/L), manual, UAB A to Type-C charging cable.

The included two pairs of eartips are size S and L, and the eartips pre-installed on the earphones are size M. To achieve better wearing effect and sound effect, users can change it according to their own wearing habits.

Compared with the OPPO Enco X charging case, the streamlined shape of the OPPO Enco X2 charging case has changed a lot. The design of the OPPO Enco X2 charging case has changed into the popular cobblestone design, which is lightweight and portable, and feels comfortable in the hand.

The top of the charging case is printed with a light gray OPPO brand logo.

There is a button on the side of the charging case for pairing earbuds.

The rear hinge of the charging case shows the product and Dynaudio jointly developed.

The Type-C interface for charging earbuds and the charging case indicator are designed at the bottom of the charging case to keep the appearance of the charging case clean.

Open the charging case cover, the internal layout is relatively compact, and the earbuds are higher than the earphone cockpit for easy removal.

There is an LED light in the middle of the earbud cabin to indicate the working status of the charging case.

Silkscreen information inside the charging case cover. charging case model: ETE02, input: 5V⎓2A, output: 5V⎓400mA, rated capacity: 566mAh/2.179Wh.

Take out the earbuds.

The metal contacts for charging earbuds are designed at the bottom of the cockpit.

OPPO Enco X2 earbuds adopts a handle-shaped in-ear design, and the earphone handle is shorter. The shell curve of the fuselage at the in-ear is more suitable for the human ear, which enhances the wearing comfort.

Back of the stem. The length of the earphone stem is shortened but the lateral area is increased, which is more convenient to touch.

The position of the earbud in-ear detection sensor. There is also the L/R logo on the sensor to distinguish the left and right ears.

The pressure relief hole near the earbud sound outlet is used to balance the internal and external air pressure of the earphone and improve the acoustic performance of the earphone.

The earbud’s main sound hole is equipped with a dust-proof net to prevent foreign objects from entering the earbud sound cavity.

Inside the eartips, there is a fine dust filter to prevent foreign objects from entering the earbud.

The top of the earphone handle is provided with a strip-shaped pressure relief hole/tuning hole, and a metal dust-proof mesh is used to prevent foreign objects from entering, which can not only play a tuning role but also play a certain decorative role.

The microphone for call pickup is designed at the bottom of the earphone handle and in the middle of the charging contact.

After actual measurement, the weight of charging case+earbuds is about 57.2g.

The overall weight of the two earbuds is about 9.7g, and the weight of a single earbud is about 4.85g.

Use a portable power tester to test the OPPO Enco X2 charging case for wired charging. The charging voltage is about 5.08V and the charging current is about 1.00A.


02/ OPPO ENCO X2 Charging Case Teardown

Pry open the headphone cockpit along the parting line and take out the headphone cockpit.

There is an FPC cable at the bottom of the earphone cockpit.

The LED light cable is fixed in the middle of the headphone cockpit.

Remove the LED light cable, and the LED light and Hall element are integrated on the cable. Among them, the hall element silk screen “AJ 1m” is used to sense the magnetic field change when the charging case is opened and closed, and realize the function of earbuds open the box and pair devices automatically.

The FPC cable is fixed in place with a magnet that attracts the earbud.

Inside the charging case, there is a special bracket under the charging cockpit.

charging case all big parts.

The hinge design used to realize the opening and closing of the charging case is in the charging case cover.

The headphone cockpit bracket in the charging case, the battery is fixed with screws above the bracket.

Remove the screw to remove the battery holder.

Front of the battery cover.

On the back of the battery cover, there is a double-sided tape to fix the FPC cable of the battery.

The charging case battery module consists of two batteries connected in parallel.

The charging case lithium-ion battery is from VDL, battery model: XE208S, rated capacity: 566mAh/2.79Wh, nominal voltage: 3.85V.

Battery coding information, the battery is from VDL, battery model: 601826, rated capacity: 288mAh/1.108Wh, nominal voltage: 3.85V, use two batteries in parallel.

The protective plate of the battery module.

The battery is provided with a circuit protection board, and the protection circuit IC on the protection board is sealed with glue.

Install the charging case motherboard at the bottom of the charging case.

The inner side of the charging case is provided with a wireless charging coil, which is used to realize the wireless charging function of the charging case.

Pairing keys on the side of the charging case.

The Type-C interface at the bottom of the charging case is open, and there are rubber rings around it for waterproofing.

The front of the internal circuit of the charging case, the pairing button board on the left, the charging case motherboard in the middle, and the wireless charging receiving coil below.

The back of the internal circuit of the charging case.

The micro-motion button on the small button switch corresponds to the pairing button on the side of the charging case.

The Type-C interface socket is surrounded by a waterproof rubber ring.

The wireless charging receiving coil is fixed on a layer of shielding sticker and pasted on the inside of the charging case shell. Wireless charging receiver coil. The transmitter coil of the wireless charger generates a certain current in the receiver coil through the electromagnetic induction effect based on the alternating current of a certain frequency, thereby transferring the electric energy from the transmitter end to the receiver end, and then supplying power to the battery in the TWS charging case.

The front and back of the circuit board are coated with a waterproof and moisture-proof coating.

Silkscreen “016 DD” IC.

Silkscreen “N8S.5” IC.

Silkscreen “H1” IC.

Silkscreen “G48 2104” IC.

SGM ‎SGM41511 battery charger and system power path management device with integrated converter and power switch for single-cell Li-Ion or Li-polymer batteries. This highly integrated 3A device enables fast charging and supports a wide input voltage range for smartphones, tablets and portable systems. I2C programming makes it a very flexible power supply and charger design solution. ‎

‎Supports multiple input sources, including standard USB host, charging ports, and USB-compatible high-voltage adapters. The default input current limit is automatically selected based on the built-in USB interface. This limit is determined by the detection circuitry in the system, such as the USB PHY. The SGM41511 complies with the USB 2.0 and USB 3.0 power supply specifications, with input current and voltage regulation. It also complies with the USB On-The-Go (OTG) power rating specification and can boost the battery voltage to deliver 5.15V at a current limit of 1.2A or 0.5A on VBUS.

‎SGM41511 provides various safety features such as overvoltage and overcurrent protection, battery temperature monitoring, charging safety timing, thermal shutdown, and input UVLO. The TS pin is connected to an NTC thermistor for battery temperature monitoring and protection in charge and boost modes according to the JEITA profile. The device also features thermal regulation, which reduces the charge current if the junction temperature exceeds 80°C or 120°C (optional). ‎‎The device is available in a green TQFN-4×4-24L package. ‎

SGM ‎Details of the SGM41511 battery charger and system power path management device.

WillSemi WS4612 load switch with current limit function, adjustable protection current, used for earbuds charging overcurrent protection.

Details of the WillSemi WS4612 Load Switch with Current Limit.

Silkscreen “P2011 GW” IC.

Prisemi P14C5N is an overvoltage and overcurrent protection chip. P14C5N supports input overvoltage and undervoltage protection, and overcurrent protection after the circuit is started. When the input voltage exceeds the input overvoltage protection threshold, the device turns off the built-in MOSFET disconnecting the input and output.

Prisemi P14C5N supports up to 30V input voltage and 3A output current. Built-in 55mΩ resistance switch, with 50ns ultra-fast overvoltage response time, supports programmable overcurrent protection, overvoltage protection supports the range of 4.5-16V, can be set with an external divider resistor, or the voltage setting pin is grounded, Use fixed 6.8V overvoltage protection. At the same time, the chip also has a built-in overheat protection function, which supports the control pin to control the switch.

Prisemi P14C5N supports handheld and portable devices, computer peripherals, USB devices and other applications, providing reliable overvoltage protection and overcurrent protection for these devices, preventing overvoltage burnout of the device or overcurrent burnout of the interface, improving user experience and reducing after-sales probability. The P14C5N is packaged in a compact DFN2*2-8L package for small volume applications.

Details of the Prisemi P14C5N overvoltage and overcurrent protection chip.

ConvenientPower CPS3008 wireless power receiving and charging management chip, single chip supports 5W wireless charging receiving, using WLCSP30 package.

ConvenientPower CPS3008 data information.

ST STM32G071 charging case MCU with integrated memory protection unit (MPU), high-speed embedded memory (up to 128 KB Flash program memory and 36 KB SRAM), DMA and extensive system functions, enhanced I/O and peripherals . Available in 28- to 64-pin packages. ‎

ST STM32G071 charging case MCU details.

Regulator IC with silkscreen “AMCS”.

Silkscreen “GPOLD” IC.

Remove the waterproof gasket of the Type-C interface socket.

“EBA61A” is silkscreened on the Type C charging port.

The LED indicator next to the Type C interface is used to indicate the charging status.


03/ OPPO ENCO X2 Earbuds Teardown

Remove the front cover of the headphone head and the back cover of the headphone handle along the parting line.

The earbud battery is fixed in the front shell of the headphone head and connected to the headphone motherboard using an FPC cable.

The magnet of the charging case is adsorbed inside the earbud.

The positive and negative electrodes of the battery are welded to the side of the battery.

The circuit of the earbud module is connected to the earbud motherboard through the BTB connector. The bone conduction sensor is located directly above.

Remove the earbud module to connect the BTB connector of the headphone motherboard.

The earbud battery and the removed headphone head.

Earbud battery information, battery model 122612, rated voltage 3.85V, rated capacity 0.219Wh.

The back of the earbud battery.

Inside the headphone cavity. There is a special acoustic bracket above the speaker unit to isolate the battery and the speaker while improving the speaker’s acoustic performance.

Remove the acoustic stand.

Acoustic stand structure.

The bottom of the acoustic stand is the bass dynamic unit of the earbud.

The tuning hole on the side of the earbud shell is equipped with a dust filter to prevent foreign objects from entering the earbud.

The earbud bass dynamic unit has a protective case on the front.

The back of the bass dynamic unit.

Removing the dynamic unit protective shell can see that the diaphragm is different from the ordinary diaphragm. OPPO Enco X2 uses cast liquid crystal material, bringing a more silky and smooth listening experience.

After actual measurement, the diameter of the bass dynamic unit is about 10.91mm.

The side of the dynamic unit protective case is provided with a phase-reversed hole structure to enhance the bass performance of the earbud.

The half black PCB under the pink glue is the sensor for earbud in-ear detection.

Below the bass dynamic unit is the tweeter plane unit, with 2103 silkscreen on the back.

Take out the tweeter plane unit, the main sound mouth inside the headphone head is protected by a dust-proof net, and the material is metal. Prevent foreign objects from entering the earbud cavity.

The front of the internal circuit of the earbud.

The back of the earbud internal circuit. A whole cable integrates a lot of functions, such as a rear-feed microphone, two speakers, an in-ear detection sensor, and it is also responsible for connecting the battery to power the earbud motherboard.

Patch for capacitive in-ear detection.

The MEMS microphone of the laser engraving “G425 1B94” is the feed-back microphone of the earbud, which is used to work together with the feed-forward microphone to achieve dual-mic noise cancelling.

On the front of the tweeter plane unit, there is a metal protective shell to prevent foreign objects from entering the earbud.

The back of the tweeter plane unit.

After actual measurement, the diameter of the tweeter plane unit is about 6.03mm.

Remove the back cover of the earphone handle, and fix the earbud motherboard on the back cover of the earphone handle.

Inside the back shell of the earbud.

The internal circuit of the back cover of the earphone handle, and the earbud motherboard uses glue to fix the position.

Remove the earbud motherboard circuit.

The internal structure of the earphone handle after removing the earbud motherboard.

There is a pressure sensor on the side of the stem.

The microphone pickup hole at the bottom of the earphone handle is protected by a dust-proof net to prevent foreign objects from entering.

Remove the cover inside the back cover of the stem.

The cavity structure of the back cover of the earphone handle.

The back of the back cover of the earphone handle is a gold-plated bluetooth antenna.

On the front of the antenna on the back shell of the earphone handle, the L/R logo is printed to facilitate the distinction between left and right ears.

The front of the pressure-sensing board.

The side of the pressure-sensitive panel. The double-layer structure relies on the capacitance change brought about by pressure for feedback operation.

The back of the pressure-sensitive panel.

The front of the earbud motherboard.

The back of the earbud motherboard.

The bone conduction device VPU located on the small board is used to pick up the sound signal of the bone during a voice call to enhance the quality of the voice call.

The MEMS microphone on the top of the earbud motherboard is the feed-forward microphone of the earbud, which is used to collect ambient sound and cooperate with the feed-back microphone for noise cancelling.

The MEMS microphone at the bottom of the earbud motherboard is used to provide the pickup function for the earbud voice/call.

The metal shrapnel on the back of the earbud motherboard that connects to the antenna.

Silkscreen “1hVp” IC.

Silkscreen “GHAN” IC.

Laser engraving “AG1b” IC.

GOODIX GH6212 is a 9-channel high-precision multi-function interactive sensor, integrating capacitance detection, pressure detection, temperature detection and other functions. It can be used in various scenarios such as proximity sensing, touch, wearing detection, press detection, and temperature detection, and has the characteristics of easy development and low power consumption.

The GH6212 provides high-sensitivity capacitive detection with aF-level capacitive resolution, with a wide capacitive detection range and excellent anti-jamming performance. Built-in 24-bit high-precision voltage detection ADC and low-power MCU support differentiated high-precision data processing requirements.

SY SY6103 is a linear charge management chip with integrated path management and a maximum charge current of 500mA. The internal integrated I2C communication module, the host can flexibly configure the charging parameters and obtain the charging status, and can report related interrupts at the same time.

SY SY6103 can complete the entire charging process for lithium batteries or lithium polymer batteries, including pre-charging, constant current and constant voltage charging. At the same time, it can automatically recharge when the battery voltage drops. The integrated path management function can ensure the system power supply first, and at the same time, it still meets the system supply voltage requirements when the battery is over-discharged. SY6103 integrates comprehensive reset functions, including watchdog timer reset for charging and discharging, key reset, one-key register reset and cold reset for easy software upgrade.

According to 52audio, the SY power management chip has been adopted by Jabra, Xiaomi, OPPO, OnePlus, realme, Transsion, MEIZU, 1MORE, Baidu, Edifier, JBL, HARMAN, Lenovo, Monster and other brands.

BES BES2600YP bluetooth audio SOC is a new generation of BES ultra-low-power bluetooth audio SoC, a three-in-one single-chip solution of bluetooth + noise cancelling + in-ear detection. It supports dual-mode Bluetooth 5.3 and multi-point connection, and integrates dual-core ARM STAR-MC1 cpu and ultra-low-power Sensor Hub subsystem, with powerful application processing capabilities. Supports open adaptive noise cancelling and AI noise cancelling. Assistive listening and spatial audio are supported. Support functions such as voice wake-up and interaction.

According to 52audio, a large number of true wireless earbuds from Samsung, Xiaomi, OPPO, JBL, 1MORE, Honor, Baidu, OnePlus, Realme, Anker and other brands have adopted the BES solution.

All components of OPPO ENCO X2 true wireless noise cancelling earphones.


04/ Summary

OPPO ENCO X2 adopts a handle-shaped in-ear design in terms of appearance, and the charging case is a popular cobblestone design, which is light and portable, and feels comfortable in the hand.

In terms of internal configuration, the earbuds are equipped with three microphones including a feed-forward microphone, a feed-back microphone and a voice pickup microphone. Support dual-mic active noise cancelling, the maximum noise cancelling depth can reach -46dB. The earbuds also have an additional bone conduction device VPU to enhance the pickup of vocals and improve the quality of the call.

In terms of circuit management, earbuds use SY SY6103 linear charge management chip. Integrated path management and internal integrated I2C communication module with a maximum charging current of 500mA, the host can flexibly configure charging parameters and obtain charging status, and can report related interrupts at the same time.

SY SY6103 can complete the entire charging process for lithium batteries or lithium polymer batteries, including pre-charging, constant current and constant voltage charging. At the same time, it can automatically recharge when the battery voltage drops. The integrated path management function can ensure the system power supply first, and at the same time, it still meets the system supply voltage requirements when the battery is over-discharged.

In terms of bluetooth audio SOC, earbuds adopts BES’s new generation of ultra-low power bluetooth audio SoC, BES2600YP, which supports dual-mode Bluetooth 5.3 and multi-point connection. Internally integrated dual-core ARM STAR-MC1 cpu and ultra-low-power Sensor Hub subsystem, with powerful application processing capabilities. Supports open adaptive noise cancelling and AI noise cancelling. Assistive listening and spatial audio are supported. Support functions such as voice wake-up and interaction. Bluetooth + noise cancelling + in-ear detection three-in-one single-chip solution, supports dual-mode Bluetooth 5.3 and multi-point connection. Internally integrated dual-core ARM STAR-MC1 cpu and ultra-low-power Sensor Hub subsystem, with powerful application processing capabilities.

In terms of sound quality, the OPPO ENCO X2 earbuds are composed of a bass dynamic unit with a diameter of 10.91mm and a tweeter plane unit with a diameter of 6.03mm. The bass dynamic unit adopts cast liquid crystal material, which brings a more silky and smooth listening experience. Both sound-generating units adopt phase-inverted design to enhance the bass.

The earbuds touch chip adopts GOODiX GH6212 high-precision multi-function interactive sensor, which integrates functions such as capacitance detection, pressure detection, and temperature detection.

In terms of internal configuration of the charging case, there is a one-key pairing button for users to update the headphone pairing. The charging case master chip adopts ST STMicroelectronics STM32G071, which integrates memory protection unit, high-speed embedded memory, DMA and extensive system functions, enhanced I/O and peripherals. There are two built-in lithium-ion batteries from Zijian Electronics, with capacities of 566mAh and 288mAh, which can provide an additional 34 hours of battery life for the earbuds.

The charging case uses multiple chips to ensure that the two batteries can be charged quickly at low temperature. The overvoltage and overcurrent protection chip adopts Prisemi P14C5N, P14C5N, which supports input overvoltage and undervoltage protection. When the input voltage exceeds the input overvoltage protection threshold, the device turns off the built-in MOSFET disconnecting the input and output. The load switch adopts Willsemi WS4612, which has its own current limiting function and adjustable protection current, which is used for earbuds charging overcurrent protection.

The battery charger and system power path management device features the SGMICRO ‎SGM41511, an integrated converter and power switch for single-cell Li-Ion or Li-polymer batteries. The charging case also supports wireless charging, and the charging coil is integrated on the back of the charging case. It adopts the ConvenientPower CPS3008 wireless power receiving and charging management chip, and the single chip supports 5W wireless charging reception.

Source: 52audio


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