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Level ILevel IILevel IIILevel IVQ:Detailed and specific questionsA: Solution Answer
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HT02 EarbudHardwareHeadphone FirmwarePower on / Pair1. How to power on and pair the headphones?Open the case means turn on.

1. First-time use: After opening the case, the LED will light up for 3 seconds (the light color depends on the current battery level) to enter pairing mode. The green LED will flash rapidly (frequency 250ms). Select "HAYLOU Flowbuds N50" in your phone's Bluetooth list and click pair to connect;

2. Already paired: The next time open the case, the earbuds will automatically reconnect to the most recently connected device;
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HT02 EarbudHardwareHeadphone FirmwarePower on / Pair
2. How to force the phone into pairing mode to connect to another phone?
When there is a pairing record before, put both earbuds inside the case, open the case and press and hold the charging case button for 3 seconds. The earbuds will enter pairing mode, indicated by a fast-flashing green light on the charging case and a fast-flashing white light on the earbuds. The new phone can then search for and connect to the earbuds.
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HT02 EarbudHardwareHeadphone FirmwarePower on / Pair3. How to clear the pairing records?Place both earbuds into the charging case and keep the case open. Press and hold the button on the charging case for 8 seconds to clear all pairing records. The LED light in the charging case will flash red 3 times to complete the reset.
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HT02 EarbudHardwareHeadphone FirmwarePower on / Pair
4. How to restore the headphones to factory settings?
Place both earbuds into the charging case and keep the case open. Press and hold the button on the charging case for 15 seconds to clear all pairing and TWS grouping records. The LED light on the charging case will stay on for 3 seconds to complete the reset.
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HT02 EarbudHardwareHeadphone FirmwarePower off5. How to turn off headphonesPlace both earbuds in the charging case, close the lid, and the earbuds will automatically power off and begin charging.

Note: If no device connects successfully within 6 minutes, the earbuds will time out and power off. Placing them back in the charging case will power them back on.
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HT02 EarbudHardwareHeadphone FirmwareTimeout shutdown6. If there is no connection, how long will the headphone turn off?

and how to restart them after they turn off?		If no device connects successfully within 6 minutes, the earbuds will time out and shut down. Placing the earbuds back into the charging case will power them back on.
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HT02 EarbudHardwareHeadphone FirmwareNoise Cancellation1. How to switch noise cancellation modes?Press and hold the MFB button on the left/right earphone for 2 seconds to switch modes. The switching sequence is: ANC ON → ANC OFF → Passthrough. The mode cycles through these modes, and a corresponding prompt tone will play each time you switch.
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HT02 EarbudHardwareHeadphone FirmwareNoise Cancellation2. How to enable adaptive noise cancellation?After successfully connecting your phone and earphones, open the Haylou Sound app, find the "Adaptive Noise Cancellation" option and turn it on. Once turned on, there will be a notification sound. The earphones will monitor the environment in real time and adjust the noise cancellation intensity accordingly.
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HT02 EarbudHardwareHeadphone FirmwareNoise Cancellation
3. What if the noise reduction effect is poor/no noise reduction effect?
3.1 Confirm that you have switched to ANC ON/Adaptive Noise Cancellation mode. When wearing the headphones, the ear tips must fit snugly in the ear canal without sound leakage (it is recommended to use 4 different sizes of antibacterial ear tips for a better fit);

3.2 Clean the headphone's sound outlet (gently sweep with a soft brush) to prevent foreign objects from blocking the seal and affecting the sound.

3.3 Keep away from environments with electromagnetic interference (such as subway stations or computer rooms), as these environments can interfere with the noise cancellation signal;

3.4 Restart the headphones or reconnect the device. If the problem persists, restore factory settings. If the issue remains, contact customer service.
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HT02 EarbudHardwareHeadphone Firmwaresound quality
1. How to enable Hi-Res high-resolution audio/LDAC decoding?
1.1 Hi-Res Audio quality is supported by default, requiring playback of 96kHz/24bit high-resolution audio files (transmission rate up to 990kbps), enhanced bass performance with dynamic bass algorithm;

1.2 LDAC decoding is disabled by default at the factory and is only supported by Android phones: After connecting, open the Haylou Sound APP to enable LDAC. The changes will take effect after the headphones restart. Go to your phone's settings → Bluetooth → Headphone Name → Audio Encoding, select "LDAC", and it is recommended to set it to "Emphasis on Audio Quality (990kbps/909kbps)".
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HT02 EarbudHardwareHeadphone Firmwaresound quality
2. What to do if the headphone sound is muffled/lacking in bass?
2.1 Clean the earphone vents and ear tips to remove earwax and dust, ensuring unobstructed sound transmission;

2.2 Open the Haylou Sound APP, select the "Bass Boost" preset in "Personalized Sound Effects," or customize the EQ (frequency response range 20-20kHz);

2.3 Confirm that your phone's decoding method is AAC/LDAC (Android), avoiding the use of only SBC decoding (the default encoding), as SBC encoding has weaker sound quality.
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HT02 EarbudHardwareHeadphone FirmwareTouch
1. What are the functions of the touch control buttons on the headphones?
The earphones come with touch controls by default, which can be customized in the app:

1. Double-tap MFB: Play/Pause music, answer/hang up calls;

2. Triple-tap left earphone MFB: Previous track;

3. Triple-tap right earphone MFB: Next track;

4. Long press L/R for 2 seconds: Switch noise cancellation mode;

Call mode (not customizable):

1. Long press L/R for 2 seconds: Reject call.

2. Double-tap L/R: Answer/hang up.
共享盘中有操作指导视频（预计下周五前上传）
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HT02 EarbudHardwareHeadphone FirmwareTouch2. What to do if the touch area are unresponsive?2.1 Ensure the earphones are properly fitted and the touch area is free of sweat and dust.

2.2 Gently wipe the earphone touch surface to keep it dry and clean.

2.3 Restart the earphones or restore factory settings to rule out firmware issues.

2.4 Avoid excessive pressure on the touch area while wearing the earphones. If the problem persists, contact customer service.
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HT02 EarbudHardwareHeadphone FirmwareBattery life / charging1. How long does it take to fully charge the earbuds and charging case?
What is the battery life?		1. The earbuds take approximately 1.5 hours to fully charge on a single charge;

2. The charging case takes approximately 2.5 hours to fully charge;

3. With ANC OFF, the earbuds offer 10 hours of battery life on a single charge, with a total battery life of 32 hours; with ANC ON, the earbuds offer 7.5 hours of battery life on a single charge, with a total battery life of 24 hours;

4. A low battery warning sound will play every 5 minutes when the earbud battery level drops below 5%.
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HT02 EarbudHardwareHeadphone FirmwareBattery life / charging
2. How to do if the earphone charging case is not charging / the charging indicator light is not on?
2.1 Check if the Type-C charging cable is making good contact with the charging port. Replace with an original charging cable and a 5V/1A standard charger (avoid using fast charging adapters);

2.2 Wipe the charging case contacts and earphone charging contacts with an alcohol swab to remove dust and oxidation;

2.3 The charging case will not show an indicator light when the battery is depleted. A red light will illuminate after 5 minutes of charging, indicating normal charging;

2.4 If it still does not charge, the charging case's motherboard may be faulty. Contact after-sales service for inspection.
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HT02 EarbudHardwareHeadphone FirmwareBattery life / charging
3. How to do if the headphones drain the battery quickly/have shorter battery life?
3.1 Disable high-power functions: LDAC decoding, adaptive noise cancellation, and low-latency gaming mode to reduce power consumption;

3.2 Disconnect Bluetooth connections from idle devices to avoid multiple devices being connected to the headphones simultaneously in the background;

3.3 Lithium batteries experience reduced battery life in environments outside of -10℃ to 45℃; avoid use in extreme temperatures;

3.4 Restore factory settings to rule out firmware malfunctions causing excessive power consumption. If the problem persists, contact after-sales service to check battery health.
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HT02 EarbudHardwareHeadphone Firmware
Charging case indicator light
1. What does the charging indicator light on the charging case represent?
When the charging cable is plugged in, the charging case's indicator light flashes red slowly; when fully charged, the charging case's indicator light remains a constant green.
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HT02 EarbudHardwareHeadphone Firmware
Headphone indicator light
2. What does the headphone charging indicator light represent?
The earphones only have a white indicator light:

1. Power On: Solid light for 2 seconds

2. Pairing Mode: Fast flashing (frequency 250ms)

3. Successful Connection: Light on for 1 second then turns off

4. Reconnection Status: Slow flashing (frequency 500ms)

5. Low Battery Warning: Flashes 3 times every 30 seconds, with a notification tone every 5 minutes.
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HT02 EarbudSoftwareHaylou Sound APPBluetooth connection
1. What to do if the connection between the headphones and the phone is unstable/frequently disconnects?
1.1 Ensure the headphones and phone are within 10 meters of each other, with no walls, metal objects, or other obstructions (Bluetooth 6.0 has a 360° unobstructed transmission range);

1.2 Turn Bluetooth off and on again on your phone, or restart the headphones (remove them from the case after 10 seconds), or restart your phone;

1.3 Clear the pairing history between the headphones and phone, then re-pair and connect;

1.4 Update the Bluetooth driver for Android phones and update the iOS system for Apple phones to ensure compatibility.
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HT02 EarbudSoftwareHaylou Sound APPBluetooth connection2. How to enable dual-device connection?1. Pair with the first device via Bluetooth, then enable dual-device connection in the app.

2. Next, turn off Bluetooth on the first device. In the Bluetooth menu of the second device (phone, computer, tablet, etc.), find the device name "HAYLOU Flowbuds N50," tap to pair, and once paired successfully, the earbuds will be connected to the second device.

3. Finally, turn Bluetooth back on the first device to reconnect. The earbuds will now be connected to both devices simultaneously.

Note: Dual-device connection is disabled by default and must be enabled via the app. It is also mutually exclusive with LDAC codec.
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HT02 EarbudSoftwareHaylou Sound APPBluetooth connection
3. How to connect the headphones after they disconnect due to excessive distance?
3.1 If the earbuds disconnect after being out of range, they will automatically reconnect to the phone if the user moves into the connection range within 6 minutes.

3.2 After 6 minutes of being out of range, the earbuds will automatically power off. The user needs to put the earbuds back in the case, open the case, power them on, and reconnect.
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HT02 EarbudSoftwareHaylou Sound APPFunction settings1. How to customize headphone sound effects?After successfully connecting the Haylou headphones to the Haylou Sound app: In "Personalized Sound Effects," select a preset sound effect (such as Pop, Rock, Classical), or manually adjust the EQ equalizer to customize the frequency response curve;
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HT02 EarbudSoftwareHaylou Sound APPFunction settings2. How to customize the noise reduction depth?In “ANC Settings”, select “ANC” mode to adjust the noise reduction depth to five levels to suit different scenarios.
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HT02 EarbudSoftwareHaylou Sound APPFunction settings3. How to enable low latency mode in the game?3.1 Low latency mode is disabled by default. After connecting your phone and headphones, open the Haylou Sound APP;

3.2 Locate and enable the "Game Low Latency" option. Enabling this mode improves audio-visual synchronization, making it suitable for competitive games;

3.3 Low latency mode will automatically disable when this mode is turned off or when the headphones are placed back in the case and powered off.
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HT02 EarbudSoftwareHaylou Sound APPOTA--upgrade the headphone firmware4. How to upgrade the headphone firmware (OTA)?【Solution】
1. Prerequisites: The earphones are connected to the Haylou Sound APP, the earphone battery is ≥ 50%, and the mobile network is stable.

2. Trigger: The APP will automatically detect updates, or you can manually go to "Device Settings → More Settings → Firmware Upgrade".

3. Operation: Click "Update Now". Do not use the earphones during the upgrade process; wait for it to complete.

【Additional Notes】 Upgrade Logic: Connecting the earphones to the APP with the charging case open or connecting them to the APP while the earphones are outside the charging case will trigger the upgrade.

Note: Do not disconnect or operate the device during the upgrade. If the upgrade fails, try restoring factory settings or contact customer support.
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HT02 EarbudSoftwareHaylou Sound APPFunction settings5. How to restore factory settings in the app?In the Haylou Sound app, tap Settings in the top navigation bar → More settings → Factory reset
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HT02 EarbudSoftwareHaylou Sound APPFunction settings6. How to clear device pairing records in the app?In the Haylou Sound app, tap settings in the top navigation bar → More settings → Clear device pairing history
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HT02 EarbudHardwareElectronic/Structural FunctionPhone call
1. What should do to if the other party can't hear me clearly/there is static/there is a lot of wind noise during a call?
1.1 Ensure the headphones fit snugly with the microphone unobstructed, and adjust the headphone angle/pickup point appropriately towards your mouth;

1.2 The headphones feature 6-microphone ENC call noise reduction + 10m/s wind noise reduction algorithm, automatically filtering wind noise during cycling/in windy conditions;

1.3 Clean dust from the headphone microphone hole (MEMS microphone) with a soft brush to prevent blockage;

1.4 Keep away from areas with strong electromagnetic interference (such as routers, induction cookers), as these environments can cause call noise.
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HT02 EarbudHardwareElectronic/Structural FunctionWear
1. What should to do if the headphones keep falling out or my ears feel sore?
1.1 Four pairs of antibacterial ear tips in different sizes are included. Change the size to fit your ear canal for a secure and pressure-free fit.

1.2 Adjust the earphone angle so that the ear tips are fully inserted into the ear canal and fit snugly against the auricle.

1.3 Avoid prolonged wear. Remove the earphones every 1-2 hours to rest and relieve ear pressure.
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HT02 EarbudHardwareElectronic/Structural FunctionWear
2. How to clean/replace ear caps when they get dirty?
The antibacterial ear caps are detachable. They can be washed with warm water and a neutral detergent (such as soapy water), dried, and reused. Avoid contact with organic solvents such as alcohol and disinfectants (which will corrode the material).
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HT02 EarbudHardwareElectronic/Structural Functionwater proof
1. Are the headphones waterproof? What precautions should to take during daily use?
1. The headphones are IPX5 waterproof, capable of withstanding daily sweat and rain splashes;

2. Caution: Do not immerse in water, do not use while showering/swimming, and avoid contact with seawater and corrosive liquids;

3. If water gets inside, immediately wipe the surface of the headphones dry and allow them to air dry naturally. Do not use a hairdryer to bake them at high temperatures.
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HT02 EarbudHardware
Packaging / Headphone Appearance
Material / Cleaning
1. How to clean and maintain earphones/charging case?
1.1 The earphone shell uses NCVM vacuum plating technology. Gently wipe with a dry, soft cloth to avoid scratching the surface.

1.2 The charging case uses aluminum alloy with anodizing process, making it drop-resistant and scratch-resistant. Wipe with a slightly damp, soft cloth to remove stains.

1.3 When not in use, place the earphones in the charging case and store them in a dry, cool environment (avoid direct sunlight and high-temperature baking to prevent material aging).
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HT02 EarbudHardware
Packaging / Headphone Appearance
Accessories
1. What accessories are included with the headphones as standard?
Standard package includes: earbuds, charging case, Type-C charging cable *1, antibacterial ear tips (4 pairs, S/M/L/XL), and instruction manual *1;
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HT02 EarbudHardwareTroubleshootingCommon Faults
1. What to do if there is no sound from the headphones / no sound from one ear?
1.1 Confirm the earbuds are connected to the phone, the phone volume is on and not muted, and test by adjusting the earbud volume control.

1.2 Check if the earbud vents are blocked by earwax or dust; clean them and try again.

1.3 No sound from one earbud: Place both earbuds in the charging case, close the lid for 10 seconds, then open the lid and remove them to trigger TWS automatic pairing (resolves master/slave earbud connection issues).

1.4 Restore factory settings or restart the device. If the problem persists, contact after-sales service to have the speaker unit inspected.
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HT02 EarbudHardwareTroubleshootingCommon Faults
2. What to do if the headphones have a static/noise issue?
2.1 Rule out audio source issues: Try different music/video files to confirm if the problem lies with the audio itself;

2.2 Keep away from devices with strong electromagnetic interference (such as routers and induction cookers), as these environments can cause abnormal signal transmission;

2.3 Turn off LDAC decoding and switch to AAC/SBC decoding for testing (LDAC decoding compatibility is poor on some phones);

2.4 Restore factory settings. If noise persists, record an audio sample and contact after-sales service for inspection (to rule out speaker malfunction).
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HT02 EarbudHardwareTroubleshootingCommon Faults
What should to do if the headphones cannot connect to the app/the app is unresponsive?
3.1 Confirm your phone's operating system version is compatible (Android 9.0+/iOS 13.0+), and update the Haylou Sound app to the latest version;

3.2 Close and reopen the Haylou Sound app, or restart your phone's Bluetooth;

3.3 Clear the app cache (Android: Settings → Apps → Haylou app → Storage → Clear cache; Apple: Uninstall and reinstall);

3.4 Disconnect the headphones from your phone's Bluetooth connection, re-pair them, and then connect to the app again.
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