In December 2020, the Nordic acoustics brand Libratone released a new generation of AIR series true wireless headphones. The appearance of the headphones continues the classic triangular handle-shaped in-ear design of Libratone. The charging case adopts a new upright and open clamshell design to ensure that the headphones are accessible At the same time, it is compact and beautiful. The overall appearance design is simple and stylish, with two Nordic style colors of warm white and blue and black, with a high degree of recognition.
Libratone’s new-generation AIR series has two products. The first release is equipped with Qualcomm QCC514x bluetooth audio SoC, which supports bluetooth 5.2 and binaural mirroring connection technology. Today 52audio is going to disassemble Libratone AIR+ which supports active noise reduction. It uses Libratone’s intelligent noise reduction adjustment technology CityMix® Smart, which can intelligently adjust the noise reduction curve according to the level of environmental noise, user movement status, wind noise, etc. , Precise noise cancellation, 52audio has already conducted a detailed experience evaluation on it.
Libratone AIR+ has also been upgraded in the noise reduction function of the call. The new acoustic/vibration dual conduction microphone enhancement technology is adopted. It can also automatically adjust the parameters according to the environmental noise to improve the clarity of voice calls; the earphones has a built-in high-quality dynamic driver, classic Denmark Tuning, support aptX audio coding; support IP54 dustproof and waterproof; single battery life of the earphones is about 6 hours, charging case provides three additional charges, supports wireless charging; with Libratone APP, it can also perform wear fit detection and personalized adjustment Operations such as noise reduction depth, gesture control, and sound effect selection. Let’s take a look at 52audio’s detailed disassembly of this product.
Previously, 52audio disassembled three products of the first-generation TRACK Air series of Little Bird: Libratone TRACK Air+ True Wireless Noise Cancelling Headphones 10th Anniversary Edition, Libratone TRACK Air+ True Wireless Active Noise Cancelling Headphones, Libratone TRACK Air True Wireless In-Ear Headphones.
| 1. Libratone AIR+ 2 active noise canceling earphones unboxing
active noise reduction true wireless earphones have also undergone major innovations in the packaging box. In response to the call for environmental protection, the packaging box is molded from 100% plant fiber pulp, which can be 100% biodegradable or recycled. The color of the packaging box is mainly white and dark blue, the upper left is the Libratone audio brand LOGO, the upper right corner is the product name “LIBRATONE AIR+ bluetooth earphones”; the center area is the rendering of the earphones; the bottom is the product slogan “high quality, Intelligent noise reduction”.
The back of the box introduces the six major features of the product, including: active noise cancelling, smart adaptation, IP54 dust and wate proof, premium sound, long battery life and wirelless charging. The product model is LTW600, the color is “green and black”, and the manufacturer is Little Bird Co., Ltd..
What’s in the box: earphones, charging case, charging cable, eartips, quick guide, manual, etc.
The charging cable is USB-A to USB Type-C interface.
Two pairs of replaceable silicone eartips, the default on the earphones is M size. Choosing the right eartips can improve wearing comfort and the effect of active noise reduction.
The charging case has an upright and open design with a very small size. The bird logo on the lid is made of metal.
On the back of the charging case, the lid uses a metal hinge, and there is a quick pairing button below. The charging case supports wireless charging, and the receiving coil is located on the back of the charging case.
52audio used ChargerLAB POWER-Z KT002 portable power tester to perform wireless charging test on Libratone AIR+ 2 active noise reduction true wireless earphones. The input power is about 3W, and the actual charging power is not so high.
Charging case side of the fuselage.
The USB Type-C charging interface is at the bottom of the charging case; the periphery of the interface is a charging indicator, which is designed to be more concealed.
In wired/wireless charging state, the light will briefly turn on white; click the pairing button, the light will flash three, two, and once respectively corresponding to the high, medium, and low power of the charging case. If the red light is on, it reminds the user to charge Up. The position of the indicator light is designed to be more concealed, making the body more beautiful, and this interaction method is also more intuitive.
52audio used the ChargerLAB POWER-Z KM001C portable power tester to perform wired charging tests on Libratone AIR+ 2 active noise-reducing true wireless headphones, and the charging power was about 2.3W.
Open the charging case and you can see the unique design of Libratone AIR+. The earphones is placed vertically in the charging case, which can be seen completely and fixed by magnetic attraction. It not only ensures that the earphones can be taken and put freely, but also takes into account the small size and beautiful appearance.
There is some product information on the inside of the box cover. Product model LTW600; battery capacity 500mAh/1.85Wh, 3.7V; input 5V⎓1A, output 5V⎓150mA, made in China, Little Bird Co.,Ltd.. The top bar is a magnet that absorbs the charging cockpit, which is used for connecting when the cover is opened, and is covered with a silica gel protective shell.
The rubber inside the cover protects the earphones from scratches.
The L/R logo on the charging cockpit is also the status indicator of the earphones.
The charging case is connected to the earphones through three Pogo Pins.
The charging cockpit shell is a slightly curved surface from the top, which fits the contour of the earphones and reduces the overall height.
Libratone AIR+ 2 active noise reduction true wireless earphones——Young Black
The earphones and charging case weigh a total of 52.2g.
The charging case alone weighs 41.4g.
The left and right earphones weigh 11g in total.
| 2. Libratone AIR+ 2 bluetooth earphones charging case teardown
After unpacking the box, we have a comprehensive understanding of the appearance of the Libratone AIR+ 2 active noise reduction true wireless earphones. The earphones continues the design language of the previous generation, and the appearance of the charging case has changed significantly, and correspondingly, there are higher requirements for the structural design. , Now we will enter the dismantling link to take a look at the internal design and chip scheme of this product.
Pry open the shell along the gap in the charging cockpit. There are multiple buckles on the side of the fuselage, and no glue is used.
The bottom shell has a wireless charging coil and a cable for matching buttons. Be careful when separating.
The battery is connected to the motherboard through the connector.
The wireless charging receiving coil is connected to the main board through the FPC and the connector.
Disconnect the connector and remove the charging case shell.
The position of the wireless charging receiving coil inside the housing.
Remove the wireless charging receiving coil, there is a matching button for the charging case on the circuit.
The solder joints of the wireless charging receiving coil are full, and the patch buttons are made on the cable to reduce the thickness.
The wireless charging receiving coil is wound with two enameled wires.
Internal structure of charging case.
Take out the cylindrical lithium battery used in the charging case.
Battery label information, supplier: EVE Energy Co.,Ltd. Model No: L1107, Noninal Voltage: 3.7V, Charging Limited Voltage: 4.2V, Rated Capacity: 500mAh, Power: 1.85Wh.
One end of the battery is a battery protection board, which is covered with barley paper for insulation, and the outside is wrapped with black insulation tape to enhance protection.
The other end of the battery.
Information on the battery cell, EVE, 13310CH, 1.85Wh, C22010129.
The negative electrode of the battery is connected to the nickel sheet of the main board, and the front and back sides are covered with insulating tape.
There is a lithium battery protection IC on the battery protection board to provide battery over-voltage, over-discharge and over-current protection; a thermistor to detect battery temperature.
The internal structure of the charging case after removing the battery.
The PCBA of the USB Type-C charging interface is fixed on the housing by screws.
On the outside of the USB Type-C charging interface, the interface is reinforced with a plastic module.
“D068” is printed on the metal of the fixed interface.
The supplier of PCBA is CEE (China Eagle Electronic Technology Co., Ltd.).
The charging interface PCBA is connected to the main board through four metal contacts.
The charging interface PCBA fixes another FPC and connector at the same time, with foam cushioning in the middle.
The lid and the metal hinge are fixed by a screw, and the two magnets next to it are used to adjust the feel when the lid is opened/closed.
The Pogo Pin module for charging the earphones can be taken out only by removing the box cover and metal hinge.
Pogo Pin module, there is L/R logo on the bracket, and the Pogo Pin position is fixed by glue and rubber hot melt.
On the other side of the Pogo Pin module, there is a larger magnet on the left and right sides of the Pogo Pin to ensure that the suction force is enough to fix the earphone. The FPC is connected to the motherboard through the BTB connector.
The location of the motherboard in the charging case.
The internal structure of the charging case after removing the motherboard.
A small piece of shielding sticker corresponding to the position of the power management chip on the motherboard.
The light transmission design of the left and right earphone indicators.
Circuit on the motherboard side.
Circuit on the other side of the motherboard.
Connect the four metal shrapnels of the charging interface PCBA.
There are three LED indicators.
The indicator lights of the left and right earphones have foam on the outer ring to avoid light leakage.
The IC of the silk screen 21Ad.
The CellWise CW2015 fuel gauge chip can accurately estimate the remaining battery power for the power display function.
According to 52audio, audio products from brands such as Huawei, Xiaomi, OPPO, Honor, OnePlus, etc. have adopted a large number of CellWise power management chips.
CellWise CW2015 details.
TI TPS7A0318 1.8V ultra-low power consumption low dropout linear regulator.
Silkscreen 09I BA’s IC.
Silk screen 4AJY IC.
TI BQ25619, an I2C controlled 1.5A single-cell step-down battery charger with 20mA termination current and 1A boost current, which integrates charging, boost converter and voltage protection functions in a single device for battery and earphones recharge.
Resonant capacitor and filter capacitor for wireless charging and receiving.
The wireless charging receiver IC comes from ConvenientPower Systems, the model is CPS4035GC, CSP package, glued reinforcement.
HDSC HC32L130F8UA MCU, used for charging case control.
| 3. Libratone AIR+ 2 active noise reduction true wireless earphone teardown
Let’s continue to disassemble the Libratone AIR+ earphones part. The appearance continues the classic shape of the Libratone TRACK Air true wireless earphone series. The color is blue-black, and the look and feel is similar to blue-gray. The earphone handle still uses anodized metal technology, with a high-end texture.
The earphone handle is an irregular triangle shape. The earphone supports tapping control, and there is no restriction on the touch area, which is relatively free; and the double-click/triple-click functions of the left and right earphones can be set for different operations through the mobile APP.
The opening on one side of the earphone handle contains a feed-forward microphone for calls and active noise reduction.
The opening on the other side of the earphone handle forms convection, which has a certain effect on reducing wind noise.
The three charging contacts on the inside of the earphone handle have the L/R logo on the bottom.
The opening of the infrared optical sensor is used for the wearing detection function of the earphone.
Pressure relief/tuning hole near the mouthpiece.
The mouthpiece is covered with a honeycomb metal grid plate to prevent foreign matter from entering the cavity.
Remove the outer cover of the earphone handle, you can see a PCBA inside the earphone handle.
Inside the cover, the bluetooth antenna of the earphones is integrated, which is connected through the contacts on the top.
Internal structure of earphone handle.
Take out the main board in the earphone handle, and connect the contacts and connectors between the components.
The PCBA inside the earphone handle is compared with the size of the RMB coin.
The left and right earphone handle circuits are on the same side.
The circuit on the other side has the same layout.
The metal shrapnel connected to the ear detection FPC, the top is the BTB connector connected to the motherboard.
Connect the metal contacts of the charging Pogo Pin.
Laser carving G366 0F14 MEMS silicon microphone is used to pick up ambient sound to assist active noise reduction and call sound pickup.
ST LIS2DS12TR accelerometer, supports single double tap function, used to realize the tap control of the earphones, the chip also supports walking/running step count record, can directly output step count information.
According to 52audio, audio products from brands including Apple, Amazon, Samsung, Huawei, Xiaomi, vivo, and Edifier all use ST sensors.
Silkscreen 269A IC.
Silk screen 4AKO IC.
The structure below the motherboard.
Connect the Pogo Pin of the bluetooth antenna.
Into the ear to detect the metal contacts of the FPC.
The Pogo Pin for charging the earphones has a magnet on the outer ring to absorb the charging case.
The pickup hole of the microphone.
The dust screen outside the pickup hole.
Disassemble the sound cavity shell along the parting line.
One side of the earphone handle housing.
The FPC for capacitive in-ear detection has the L/R logo on it.
Connect the Pogo Pin of the bluetooth antenna.
The internal structure of the sound cavity of the left and right earphones is compared, and two-dimensional code labels of different colors are affixed on the motherboard.
The bottom structure of the sound cavity is contrasted with a small PCBA.
The speaker unit is connected to the main board through the FPC; the positive electrode of the battery is welded to the edge of the main board. The solder joints are very round and full.
Solder the FPC connected to the speaker unit, and the button battery is under the motherboard.
Complete circuit inside the sound cavity.
The size comparison of button battery and RMB coin.
Button battery information, rated capacity 60mAh, energy 0.222Wh.
The button battery used in the earphones comes from EVE, model ICR1254, with a diameter of 12mm, a thickness of 5.4mm, and a rated voltage of 3.7V.
According to 52audio, there are already true wireless earphones of Samsung, Buttons, ZMI, UGreen and other brands that use EVE button batteries.
Two PCBA and RMB coin size comparison.
The two PCBAs in the earphone are connected by a flexible flat cable, with a button battery in between.
Structure on the other side of the circuit.
Contact shrapnel for the negative electrode of the battery.
Analog Devices ADAU1788 audio DSP chip, dual-channel ADC, independent DAC, active noise reduction function for headphones.
According to 52audio, many true wireless earphones from brands such as Huawei, Bose, 1MORE, Amazon, and Libratone have adopted ADI DSP for active noise reduction.
ADI ADAU1788 detailed information.
Infrared optical sensor.
The CellWise CW2015 fuel gauge chip is used to estimate the power of the earphones battery. The fuel gauge chip in the charging case is the same model.
Screen printing CPF K23 battery protection IC.
The feed-back microphone used for active noise reduction and call noise reduction functions, the glue is very viscous, and the silk screen on the silicon microphone is taken away when the glue is removed.
There is a shielding sheet where the other motherboard contacts the battery.
The circuit on the motherboard is mainly the peripheral circuit of the bluetooth audio SoC.
The memory of the silk screen Z7CLW1941 stores bluetooth configuration and other information.
Libratone AIR+ uses Qualcomm’s QCC5141 low-power bluetooth audio SoC, and is one of the first true wireless products using Qualcomm’s new solution.
Qualcomm QCC5141 supports bluetooth V5.2, supports aptX, uses Qualcomm TrueWireless Mirroring technology to connect to mobile phones, and the left and right earphones can be switched seamlessly and quickly. Qualcomm QCC514x series integrates hybrid active noise reduction technology; supports ultra-low latency transparent transmission of external environmental sounds; especially provides always-on wake word activation for multiple voice ecosystems. And the QCC514x series has been optimized in terms of power consumption for different actual scenarios, achieving ultra-low power consumption control while providing strong sound quality and connectivity.
According to 52audio, well-known brands such as Anker, Bose, Beyerdynamic, B&O, Cleer, Edifier, Jiss, Bird, Libratone, Microsoft, OPPO, vivo, Sony, 1MORE and other well-known brands have adopted Qualcomm bluetooth. Audio SoC.
The internal structure of the sound cavity shell.
The opening window of the infrared optical sensor is a filter protection cover.
The internal structure of the tuning/pressure relief hole, the feed-back microphone is also in this position.
Speaker unit side.
The speaker unit size is about 5mm.
All components of Libratone AIR+ 2 active noise reduction true wireless earphones.
Libratone AIR+ 2 active noise reduction true wireless earphones have made a big breakthrough in the appearance of the charging case. The new upright and open design ensures that the earphones can be taken and put freely while taking into account the compact and beautiful size; the design of the charging case indicator is also very clever. It can display the battery level and the charging status. The appearance of the earphones continues the classic shape of the TRACK Air true wireless earphone series. The earphone handle is made of anodized metal to enhance the sense of quality; the overall product is stylish and beautiful, with a high degree of recognition.
In terms of internal circuits, the charging case has an excellent structural design. The components are mainly connected through connectors and metal shrapnel, which can improve production efficiency; the charging case inputs power through the USB Type-C charging interface. TI BQ25619 is used to charge the battery and earphones. The wireless charging receiver IC is ConvenientPower Systems CPS4035, the cylindrical lithium battery comes from EVE, the capacity is 500mAh, CellWise CW2015 is used to estimate the battery power, the HDC HC32L130F8UA microcontroller is responsible for the whole machine control; the manufacturer of the charging case PCBA is China Eagle Electronic Technology Co., Ltd ..
In the earphone part, Libratone AIR+ 2 adjusted the housing structure of the feedforward microphone, and the microphone pickup hole was transferred from the bottom of the earphone handle to both sides of the earphone handle to reduce wind noise; in addition to the optical sensor, the earphone was also added to the ear Capacitive sensing FPC is used for in-ear detection; besides, its internal structure is similar to the previous generation. There is a motherboard in the earphone handle, and there are two motherboards in the sound cavity with button batteries. The size of the speaker units are all It is 5mm.
Libratone AIR+ 2 is first launched with Qualcomm QCC5141 low-power bluetooth audio SoC, supports bluetooth V5.2, aptX encoding, adopts Qualcomm TrueWireless Mirroring connection technology, faster switching between single and dual headphones, and lower overall power consumption; active noise reduction function is adopted Hybrid noise reduction solution, the noise reduction chip is ADI ADAU1788; call noise reduction adopts a dual-mic solution, which picks up the sound generated by the vibration inside the ear canal and the external environmental sound separately, and performs noise reduction processing through related algorithms; both noise reduction functions The parameters can be adjusted automatically according to the degree of noisy environment; the tap control function is realized by the ST acceleration sensor; the button battery is also from EVE, the capacity is 60mAh, and the CellWise CW2015 is used to estimate the battery power.
Related Products of Libratone: