How to make stereo sound on Xiaomi Mi 9T: all ways + problem solving

Xiaomi Mi 9T (aka Redmi K20) is one of the brand’s most popular smartphones, but many users are faced with an unexpected problem: instead of the promised stereo sound, the device plays audio in mono mode. The reason lies in the architecture of speakers and system settings. In this article, we will discuss how to activate the stereo effect through standard menus, engineering settings and third-party applications – and why sometimes the sound remains mono even after all the manipulations.

It's important to understand that the Mi 9T is physically equipped with two speakers, but by default the second one works only as a conversational speaker (for calls). To use it for media, you will need to interfere with system parameters. We tested all methods on MIUI 12-14 firmware (including global and Chinese versions) and highlighted those that work guaranteed. If you are not ready to experiment with engineering menus, at the end of this article there are alternative solutions.

Warning: some methods require root or unlocked bootloader rights, which can cancel the warranty and damage the system if you do not act correctly, and you perform all the manipulations at your own risk.

Why is Xiaomi Mi 9T sound mono, not stereo?

The Mi 9T has two dynamic components:

• 🔊 Main speaker (lower, multimedia) – reproduces the full frequency range.
• 📞 Speaker (top, above the screen) – optimized for voice calls and notifications.

By default, the system uses only the lower speaker for music, video and games, and the upper one only turns on when calling or for notifications (such as an alarm clock), a solution Xiaomi explains:

• ⚖️ Volume Balance – Two speakers can create an imbalance in sound.
• 🔋 Saving charge – the operation of two speakers increases energy consumption.
• 🛠️ Protection against overheating - a long load on both speakers increases the temperature of the body.

But there's a firmware feature that allows you to activate the stereo mode -- you just need to get it right, and here's all the working methods, starting with the safest ones.

Method 1: Enabling stereo sound through the engineering menu (without root)

The most reliable method is activation via the Engineering Mode, which does not require superuser rights, but caution is needed: incorrect settings can lead to audio failures.

Instructions:

1. Open the Phone app and type the combination: ##36446337## (or ##ENG###).
2. In the menu that appears, select Hardware Testing → Audio → LoudSpeaker Mode.
3. Find the Speaker Mode option and set the Stereo value (or Dual Speaker, depending on the firmware version).
4. Save the settings and restart the smartphone.

If the combination doesn't work, try the alternative code: ##4636## → Hardware info → Audio. Some firmware may have different paths.

Check the version of MIUI in Settings → About the phone

Make sure that SIM-Card inserted (some codes require an active network)

Battery charge of at least 50%

Record the current sound settings (volume, equalizer)

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⚠️ Note: On some versions MIUI 13+ The engineering menu can be blocked, and if you don't enter the code, it doesn't work for you. ADB or third-party applications.

Method 2: Activation through ADB-teams (without root)

If the engineering menu is not available, you can turn on stereo through ADB (Android Debug Bridge), which works on most firmware, but requires a connection to a PC.

Step-by-step:

1. Download and install Platform Tools (or Minimal ADB).
2. Turn on your smartphone Debugging by USB (Settings → About Phone → MIUI Version → 7 times tap on version → return to Additional → For developers).
3. Connect the Mi 9T to your PC and enter in the command line (in the folder with ADB):

adb shell settings put global stereo_speaker true

To check the current state, use:

adb shell settings get global stereo_speaker

If the command returns true, the stereo is activated. Reboot the device.

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If ADB not seeing the device, try reinstalling drivers or using another USB-cable (preferably original).

Method 3: Applications for forced inclusion of stereo sound

If previous methods have failed, third-party utilities may be available, which do not guarantee 100% results, but often help with custom firmware or modified versions of MIUI.

Top.-3 tested applications:

For Dual Speaker Mod:

1. Install the application and open it.
2. Choose the Enable Dual Speaker.
3. Reboot your smartphone.

⚠️ Attention: Apps like ViPER4Android If you have wheezing or distortion after installation, delete the program and reset the sound settings to Settings. → Sound. → Additionally. → Reset.

Method 4: Manual editing of configuration files (for advanced ones)

This method is only suitable for root-rights or custom recovery (TWRP) users, and involves editing system files, which can cause the device to fail in case of errors.

Instructions:

1. With Root Explorer or FX File Manager, go to /system/vendor/etc.
2. Find the file. mixer_paths_tasha.xml (or similar, depending on the firmware).
3. Open the file in the text editor and find lines with the speaker.
4. Add or change the settings for the second speaker, such as:

<path name="speaker-stereo">


<path name="Speaker Left" />




<path name="Speaker Right" />




</path>

The corresponding values can be found in thematic forums (e.g. XDA).

1. Save the file and restart the device.
2. Check the sound – if there is any distortion, return the original file.

Problems and Solutions: Why Does Stereo Sound Not Work?

Even after all the manipulations, the sound can remain mono, and let's look at the typical causes and ways to eliminate them:

Critical information: In some batches of Xiaomi Mi 9T (especially early 2019 revisions), the top speaker is not physically connected to the multimedia audio track. Check this by calling the device - if the sound is only from the bottom during the call, your model does not support stereo at the software level.

Alternative ways to improve sound without stereo

If you can not turn on stereo sound, you can improve the audio by other methods:

• 🎧 Use support headphones AAC AptX – they will give better quality than speakers.
• 🔊 Connect an external Bluetooth speaker (e.g. Xiaomi Mi Portable Speaker).
• 📱 Set an equalizer (such as Wavelet or built-in Settings) → Sound. → equalizer).
• 🔄 Activate Dolby Atmos in the sound settings (available on the MIUI 12+).

To activate Dolby Atmos:

1. Go to Settings → Sound → Sound quality and effects.
2. Choose Dolby Atmos.
3. Set up a profile for Music or Film.

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Even without stereo sound, the right equalizer and Dolby Atmos settings can significantly improve audio perception by adding volume and clarity.

FAQ: Frequent questions about stereo sound on Xiaomi Mi 9T