At the MateBook series conference in August, Huawei brought a new neck-mounted bluetooth headphones——Huawei FreeLace Pro, as a new iteration of FreeLace. In appearance, it inherits the overall design language of the previous generation product, flat U-shaped collar and wire control board, and unique embedded USB-C interface. The difference is that the earphone body adopts a flat design, which is more coordinated with the whole machine; the eartips are replaced in order to submerge, and the eartips and earwings are integrated.
The configuration uses bluetooth version V5.0. The 14mm moving coil unit is equipped with an independent low-frequency sound guide. The sound quality is tuned by a professional audio team; it supports active noise reduction and ambient sound transmission mode, and the left earphone is built in for Sensors that turn on/off and switch the noise reduction mode; also support the magnetic switch function, which can automatically control the connection status; support fast charging in terms of battery life, can achieve 16 hours of battery life in ANC mode, and can be directly plugged into mobile devices such as mobile phones and tablets. Its emergency charging; supports low-latency gaming mode and supports fast switching between different devices.
The active noise reduction TWS true wireless headphones FreeBuds 3 previously launched by Huawei uses semi-open active noise reduction, which makes the actual noise reduction effect experience mixed. However, the noise reduction effect of Huawei FreeLace Pro gave me enough surprises. Let’s take a look at the internal structure of this product together.
Huawei FreeLace Pro teardown
First, open the left cavity from the structure. The cavity contains the battery unit.
The U-shaped collar is connected to the left cavity in a snap-fit manner.
There is a lot of waterproof glue at the junction of the earphone cord and the cavity rubber plug.
The left cavity is disassembled.
The earphone wire and the battery wire are connected through a small board, and the solder joints are glued and reinforced.
The battery unit has a transparent plastic bracket with a groove on the bracket, and the earphone cable extending from the motherboard is embedded in the groove.
The outside of the battery is wrapped with black insulating tape, and the information is printed on the lithium-ion polymer battery, HUAWEI, model: HB411141ECW, 150mAh/0.57Wh/3.82V, charging limit voltage: 4.4V, executive standard: GB 31241-2014 and other information.
The back of the battery.
Tear off the black tape, the internal battery information has Model: 401136, Capacity: 0.59Wh, Voltage: 3.82V. According to my information, the battery comes from ATL.
The battery has a small circuit protection board, and the earphone wire is welded to the small board, and is reinforced with a large amount of hard glue.
Go to the cavity on the right and open the connection structure between the U-shaped collar and the cavity.
In addition to the outer metal shell of the right cavity, there is a protective shell inside.
Cut the outer metal shell.
Pry open the metal shell, it can be seen that two metal elastic contacts are in contact with the shell.
A metal sheet fixed by spot welding on the inner wall of the metal shell.
There is a layer of rubber film inside the function keys.
Power keycap on the side of the right cavity.
There is also a layer of silicone pad on the function buttons on the internal protective shell.
There is a ground shielding metal dome on the inner protective shell.
There is an indicator light guide on the side of the internal protective shell, and the power button is covered by a white cushion.
The microphone on the other side has an opening and is covered by a dust-proof net, which is used for call radio.
The internal protective shell adopts the design of flip cover.
Open the protective cover to see the internal structure.
The internal structure of the protective cover has a heat dissipation sticker corresponding to the SOC position.
A QR code label is affixed to the main control chip on the front of the motherboard.
The power button cable is connected to the main board through a bayonet.
The power button flat cable female seat on the main board.
Remove the main board and the internal structure of the cavity.
Uncover the white cushion on the side of the cavity, and close-up of the power button. There are metal dome on it, which can protect the fretting and increase the rebound feel.
The back of the motherboard.
The front of the motherboard.
A close-up of the jog button on the motherboard.
A close-up of the LED indicator.
The microphone opening on the motherboard is covered by a dust-proof net.
SINOMUC MC9934 8-bit single-chip microcomputer, used to trigger a reset to transmit the bluetooth signal again when the bluetooth headphones fails to connect to ensure that the bluetooth does not crash. At the same time, it has ultra-low standby power consumption and extends the battery life of the bluetooth headphones.
MC9934 adopts DFN8 package, has 8-bit CPU core, 1K×14-bit OTP program memory and 50 bytes SRAM general data memory; built-in high-frequency and low-frequency RC oscillator, used as the system clock source at high or low frequency ; There are two working modes: run mode and sleep mode; internally equipped with self-oscillating watchdog counter and timer.
The metal contacts connected to the grounded metal dome on the main board.
Silk screen ALH IC.
MEMS silicon microphone of laser carving R026.
HYPWR HP2601 overvoltage protection and lithium battery charger front-end protection IC.
HYPWR HP2601 detailed information.
The CellWise CW2017 fuel gauge chip supports battery NTC temperature measurement and battery ID identification, and can accurately calculate the remaining battery power. It has the characteristics of small size, low power consumption, and no current-sense resistor.
CellWise CW2017 detailed information.
CellWise CW6305 lithium battery charging IC, input withstand voltage 28V, maximum charging current 500mA, I2C interface, 7uA ultra-low static power consumption, dynamic adjustment of charging voltage and current, meeting JEITA standards, and meeting the latest IEC-62368-2018 standards.
According to 52audio, Honor FlyPods 3 true wireless active noise reduction headphoness, OPPO Enco M31 neck-mounted wireless bluetooth headphoness also use CellWise CW6305 charging management IC.
The main control chip is BES BES2300, which is a fully integrated adaptive active noise reduction solution that supports bluetooth 5.0, LBRT low-frequency forwarding technology and dual-mode bluetooth 5.0; supports third-generation FWS full wireless stereo technology, dual microphones, etc., using 28nm, BGA package.
BES BES2300 also supports external heart rate sensors, acceleration sensors and other external sensor devices and eMMC flash memory, which can achieve the purpose of playing music on external storage devices.
According to 52audio, Huawei, OPPO, Xiaomi, Meizu, JBL, 1MORE and many other well-known audio brand products have built-in Hengxuan solutions.
Coming to the earphone part, first disassemble the right ear.
The speaker unit small board is welded with the wire and reinforced with glue.
The internal structure of the right ear cavity.
A microphone is fixed on the cavity wall and connected to the small board through a flat cable.
Bass inverter tube.
The front of the feedforward microphone unit is covered by a dust-proof net.
The MEMS feed-forward microphone of LaserDiao R029 is used to collect external noise.
Remove the speaker unit, and the back-feed microphone is embedded in the output tube.
The microphone is fixed by hot melt, the outside is covered with a dust-proof net, and the edge of the cable is fixed with glue.
The backfeed microphone is slotted in the cavity.
The MEMS backfeed microphone of LaserDiao R030 is used to collect the internal noise of the ear canal.
According to 52audio’s actual measurement, the speaker unit size is about 14mm, which is consistent with the official publicity.
Disassemble the left earphone.
The internal structure of the left earphone, the left earphone has a touch unit.
Remove the left earphone plate, the back of the plate has a magnet for magnetic switch function.
The touch unit in the left earphone is connected to the small board through a cable.
Disassemble the front components of the left headphone.
Disassemble the back components of the left headphone.
There are a touch chip and a Hall element on the touch unit cable, which are used to switch the noise reduction mode and detect the earphone adsorption state.
All components of Huawei FreeLace Pro noise-reducing bluetooth headphones.
Huawei FreeLace Pro noise reduction neck-mounted bluetooth headphones adopts an angular design in appearance, and the overall feeling is relatively stable, revealing a strong business style. The flat U-shaped collar is comfortable to wear and not easy to roll; the integrated design of headphones and earwings makes the wearing more fit the auricle and improves the noise reduction effect; the unique embedded USB-C interface not only saves the trouble of wearing a charging cable when going out , It can also realize fast bluetooth connection; the headphones has a magnetic switch function, which can intelligently recognize the status of the headphones, automatically control the connection, and save unnecessary power consumption.
In terms of internal structure, the design is relatively compact and has multiple protections. The welding points of the wires are coated with a large amount of glue for protection, and there are many soft cables to save internal space; the right cavity contains a 0.59Wh polymer lithium ion battery, which can provide the headphones with a noise reduction mode of 16h battery life, and It is equipped with a circuit protection board, and there is a circuit protection IC on the protection board.
The main board is located in the cavity of the wire control board on the right. The main control chip is BES BES2300, which integrates adaptive active noise reduction technology solution, supports bluetooth 5.0, and a chip achieves high sound quality and active noise reduction effects; the input uses HYPWR HP2601 overvoltage protection and Lithium battery charger front-end protection IC for input overvoltage and overcurrent and enhanced lithium battery charging protection. In other aspects, the CellWise CW6305 lithium battery charging IC is used to dynamically adjust the charging voltage and current in real time; the CellWise CW2017 fuel gauge chip provides accurate calculation of the remaining battery power for the headphones.