Why the headphones don’t connect to the Xiaomi T9 and how to fix it
Wireless headphones have become an integral part of everyday life, from listening to music to calling and watching videos. However, even with modern smartphones like the Xiaomi Redmi T9 (model M2006C3LG with a chipset MediaTek Helio G85), users face problems synchronizing over Bluetooth. In this article, we will examine not only the basic connection procedure, but also the nuances that the manufacturer does not say, from hidden audio settings to the diagnosis of hardware conflicts.
The Redmi T9 features Bluetooth 5.0 support with AAC codec (but no aptX or LDAC), which affects sound quality and connection stability. If your headphones — like Xiaomi AirDots or Sony WH-1000XM4 — refuse to connect, the problem may lie in firmware, power saving settings or even physical interference.
Preparation of headphones and phone for pairing
Before you start connecting, make sure both devices are ready to sync. For Xiaomi Redmi T9, it is critical to update the firmware to the latest version of MIUI (current for 2026 - MIUI 14 based on Android 12). You can check the version in the Settings menu → About Phone → MIUI version.
As for the headphones:
- 🔋 Make sure they are charged (the indicator should flash or burn green).For example, AirDots Pro 2 requires a minimum of 20% charge for stable pairing.
- 📱 Put your headphones in search mode. For most models, this is holding the power button for 3-5 seconds until the blue/red LED flashes.
- 🔄 If the headphones have already been connected to another device, reset their settings (usually holding the button to 10).+ seconds before the indicator is reset).
Important for Xiaomi Redmi T9: If you used headphones with iPhone before, they could save your profile HFP (for calls instead A2DP (In this case, reset the list of conjugated devices on the phone to Settings. → Connected devices → Bluetooth → Settings (⚙️) → Delete all devices.
Step-by-step: how to connect headphones via Bluetooth
Follow this algorithm to sync your headphones with the Redmi T9:
- Activate Bluetooth on your phone: swipe down the screen to open the notification bar, and click on the Bluetooth icon (or go to Settings → Connected Devices → Bluetooth).
- Start a device search: tap the Device Search button (or Add a new device).
- Select headphones from the list: When your model name appears in the list (such as Mi True Wireless Earphones 2), click on it.
- Confirm the pairing: on the phone and (if required) on headphones. PIN-code - default is 0000 or 1234.
If the headphones don’t appear in the list, try:
- 🔄 Reboot the phone’s Bluetooth module: Turn off and turn on Bluetooth again in the settings.
- 📵 Make sure that the headphones are no more than 10 meters from the phone (optimally 1-2 meters).
- 🚫 Disable other Bluetooth devices (fitness bracelets, smart watches) that may interfere.
☑️ Checking before connection
Adjusting the sound after connecting
After successful pairing, check the sound quality. On the Xiaomi Redmi T9, hidden settings are available that will improve playback:
- Select codecs: Go to Settings → Sound → Bluetooth Sound Quality and select AAC (for balance of quality and stability) or SBC (for compatibility).
- Mono/Stereo: If the sound is only in one headphone, check the Bluetooth connection profile – it should be A2DP (stereo) and not HFP (mono for calls).
- Equalizer: In the Mi Music app or Google Play Music, set up an equalizer for the genre (e.g., Bass Boost for Hip Hop).
For headphone models with ANC (active noise cancellation) support, the Redmi T9 may require additional software. For example, for Sony WH-1000XM4, install the Sony Headphones Connect app from Google Play.
| Problem. | Possible cause | Decision |
|---|---|---|
| The sound is interrupted. | Interference from 5GHz Wi-Fi or other devices | Switch to 2.4GHz router or disable other Bluetooth gadgets |
| Low volume. | Limitation in Android settings | Turn off the Safe Volume Level in Settings → Sound → More |
| Sound delay (lag) | SBC codec is used. | Switch to AAC in Bluetooth settings |
| The headphones shut down on their own. | MIUI Energy Conservation | Add Bluetooth to exceptions: Settings → Battery → Battery Optimization → All apps → Bluetooth |
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If the headphones are connected but the sound is distorted, try turning off the Absolute Volume function in Settings → System → For Developers (if the partition is activated).
Common mistakes and their solutions
Even after a successful connection, Redmi T9 users face typical problems.
⚠️ Warning: If the headphones are plugged in but immediately shut off, check the automatic shutdown settings in their proprietary app (e.g. Mi Earphones for Xiaomi models). Sometimes the power saving feature breaks the connection after 5-10 minutes of inactivity.
Mistake: "I couldn't connect"
- 🔄 Reboot both devices.
- 📱 Remove the headphones from the list of conjugate devices and reconnect.
- 🛠️ Update the firmware on the headphones (if available). For example, for AirDots Pro 2, updates are posted to Mi Home.
Mistake: The sound is only in one headphone
- 🎧 Check if Mono mode is activated (for calls). Switch the profile to Stereo in Bluetooth settings.
- 🔋 Charge headphones – sometimes the discharge of one of them leads to a disconnection channel.
- 🔄 Reset the headphone settings (usually by holding the button for 15 seconds).
What to do if the headphones are connected as a "Device for calls"
Optimizing Connection for Games and Video
For gamers and video enthusiasts, the lag is critical. On the Redmi T9, it can be reduced:
- 🎮 Enable the game mode in Settings → Special facilities → Game mode. This prioritizes resources for Bluetooth.
- 📶 Turn off Wi-Fi Direct and NFC, If you don’t use them, they will cause interference.
- 🔊 Use the codec. AAC instead SBC (Although it is less stable, the delay is lower).
To check for delay, use the test in the SoundAbout app (available on Google Play).The optimal lag value for games is less than 100 ms. If the delay is higher, try:
- 🔄 Reconnect the headphones.
- 📱 Restart your phone in Safe Mode (hold the power button) → Safe mode) to eliminate the impact of third-party applications.
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For a minimum lag in games, disable Bluetooth AVRCP 1.6 in the developer settings (if the partition is activated).
Alternative ways of connecting
If Bluetooth refuses to work, consider alternatives:
- 🎧 Bluetooth 5.0 Adapter: Connects to a 3.5mm connector (if you have one in your Redmi model) T9) It sends a signal to headphones without a lag.
- 📱 FM-transmitter: for example, Baseus FM Transmitter, which transmits sound over radio frequency.
- 🔊 Aux cable: if the headphones support wired connectivity (e.g. Sony) WH-1000XM4 cabled).
It is important for adapters to choose a model that supports aptX Low Latency if your headphones are compatible with this codec, such as the 1Mii B06 Plus or Avantek APA-BTHD500.
⚠️ Note: When using adapters in the connector 3.5 mm on the Redmi T9 The headphones may not work, but you'll need a separate headset cable to make calls. CTIA/OMTP.