How to switch the sound to headphones on Xiaomi Redmi 9: all ways + error solving

Why doesn’t the sound switch to the headphones automatically?

You've connected your headphones to the Xiaomi Redmi 9, but the sound still goes through the speakers? This problem is familiar to many MIUI smartphone owners, especially after system upgrades or when using unoriginal accessories. In 80% of cases, it's not the hardware defect that's to blame, but the software settings or the conflict with the applications.

On the Redmi 9 (models M2003J15SC/M2003J15SS), the switching of sound to headphones can be blocked due to:

• 🔹 Dirty connector 3.5 mm – oxidation of contacts interferes with the recognition of the connection;
• 🔹 Incompatible Bluetooth headphones – some models require manual selection in settings;
• 🔹 Disruption of service media.audio_flinger — System process responsible for routing sound;
• 🔹 Application restrictions – for example, YouTube or games can ignore system settings.

In this article, we've got 5 proven ways to force the audio to switch to the headphones, including the hidden MIUI 12/13 settings and Bluetooth bug-bypass, and we'll also look at what to do if the headphones are defined by the system, but the sound still goes through the speakers.

Method 1: Manually switching through the notification panel

The fastest method is to use the Quick Settings Panel, which works for both wired and Bluetooth headphones, but only if the system recognizes them correctly.

1. Connect the headphones to the smartphone (insert the plug or activate Bluetooth).
2. Swipe your finger down the screen to open the notification bar.
3. Find the Sound icon and hold it for 2 seconds.
4. In the menu that opens, select Headphones (or the name of your Bluetooth model).

If the headphones are not on the list, the system has not recognized the connection.

• 🔌 Wired headphones: try to remove / insert the plug several times, clean the connector from dust;
• 📶 Bluetooth: Disable and reconnect the device in Bluetooth settings.

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If the sound icon on the notification panel is gray (inactive), reboot the phone – this will reset the audio system’s temporary errors.

Method 2: Sound settings in MIUI (hidden parameters)

MIUI has a hidden menu where you can force the output of sound to the headphones — even if they are not automatically determined, a technique that is particularly useful for Redmi 9 with custom firmware or after resetting.

Instructions:

1. Open the Settings app → Sound and vibration.
2. Scroll down and click on the Additional Settings.
3. Select Routing of Sound (if there is no point, go to Method 3).
4. In the Output Device section, install Headphones or Bluetooth A2DP.

On some versions of MIUI 12.5+, this item may be called Select Output Device or hidden behind the Developer Option.

Method 3: Forced switching through the engineering menu

If standard methods fail, you can use the engineering menu (#4636##) which is suitable for power users and requires caution - incorrect settings can lead to audio failures.

Step-by-step:

1. Open the phone app and enter the combination: ##4636##
2. Select Phone Information (or Testing in English firmware).
3. Scroll down to the Audio block and press Volume.
4. In the Media section, install Headset instead of Speaker.
5. Press Set and restart the phone.

Attention! Changes in the engineering menu can affect the microphone volume or sound quality. If the sound is lost after manipulation, reset the audio settings:

⚠️ Note: Do not change the parameters in the sections RF Band or Network – This can disrupt mobile network.

Method 4: Switching sound for individual applications

Some programs (e.g. YouTube, TikTok or games) ignore the global audio settings and output audio only to speakers.

For Android 10+ (MIUI 12 and later):

• 🎵 Open an app that has no sound in the headphones.
• 🔊 Swipe down the notification panel and hold the sound icon.
• 📱 In the list of devices, select Headphones (even if they are already connected).

For older versions of MIUI:

Use third-party utilities like SoundAssistant (from Samsung, but it works on Xiaomi) or Audio Router, which allow you to force the audio to be redirected for each application separately.

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If the sound in the headphones appears only after restarting the application, the problem is in the program cache. Clear the application data in the App settings → [Program name] → Storage → Clear the cache.

Method 5: Solving problems with Bluetooth headphones

Bluetooth audio on Redmi 9 often suffers from latency or automatic speaker switching.

To activate aptX (improved Bluetooth codec):

1. Activate Developer Mode (7 times click on the MIUI version in your phone settings).
2. Return to the additional settings → For developers.
3. Find Audio codec and select aptX or aptX HD.
4. Reconnect the headphones.

What do you do if nothing helps?

If the sound does not switch to headphones, check:

1. Hardware malfunctions: 🔧 Call the 3.5mm multimeter connector (resistance between contacts should be ~10.50 Om). 🔊 Connect the headphones to another device – if they don’t work there, the cable is the problem.
2. Programmatic failures: 📱 Reset the sound settings: Settings → System system → Resetting settings → Reset the sound settings. 🔄 Update. MIUI Up to the latest version (sound bugs are often patched).

Conflict with annexes:

• 🚫 Remove programs to change sound (ViPER4Android, Equalizer – they can block system routes.
• 🛑 Check permissions for applications in Settings → Annexes → Permits → Microphone.

Try connecting headphones with a microphone – if the microphone is working and there is no sound, the audio output is to blame.

If the plug is faulty, it will cost you to replace it. ~800–1500 ₽ (depending on the service center).