How to turn on aptX on Xiaomi Redmi 9: the full guide

Owners of budget and mid-budget smartphones often wonder about the possibility of improving the quality of wireless sound, and the Xiaomi Redmi 9 is no exception to this list.The standard codec set offered by the manufacturer by default is often limited to basic SBC and AAC, which does not always satisfy demanding audiophiles. Technical upgrade of the audio tract through software methods can significantly change the experience of listening to music through Bluetooth headphones.

However, activating advanced codecs isn’t always a trivial task and requires understanding the Android architecture and the features of the MIUI shell. In this article, we’ll discuss in detail whether your gadget supports high-quality hardware decoding and what steps you need to take to force it to activate. It’s important to know that Redmi 9 is based on the MediaTek Helio G80 processor, which has limitations in supporting codecs at the driver level.

Before you start to do complex manipulations, you need to evaluate the real-world capabilities of your device and the connected acoustics. Hardware compatibility is the foundation without which software settings will be useless. We'll look at both standard methods and deeper system interventions.

Redmi 9 hardware and codec support

The first step in any technical study is to understand the “iron” part of the issue. The Redmi 9 smartphone is equipped with a MediaTek Helio G80 chipset, which refers to the initial performance segment. The performance of the Bluetooth module in conjunction with this processor determines the basic set of supported audio data technologies.

Unlike the flagship Qualcomm Snapdragon-based solutions, where support for aptX, aptX HD, and even LDAC is often built into the licensing and hardware DSP layer, MediaTek’s low-end solutions may not have hardware support for Qualcomm’s proprietary codecs. This means that even with software enabled, the physical chip may not be able to handle real-time stream coding without artifacts.

However, the Android operating system provides tools to manage these parameters, so if the Bluetooth driver in the kernel contains codec libraries, they can be activated, and if support is not available at the hardware or modem firmware level, software crutches will not be able to create sound from nothing.

⚠️ Attention: Attempting to force unsupported codecs at the driver level can lead to unstable operation of the Bluetooth module, periodic connection breaks or complete failure of the wireless headset to work with a smartphone.

It is also worth considering that for the work of aptX technology, it is necessary to support this standard not only from the smartphone, but also from the receiving device - headphones or speakers. If your headset supports only SBC, turning on the settings on the phone will not give any effect.

Check current Bluetooth settings in the developer menu

The main tool for managing hidden Bluetooth settings in Android is the developer menu. This is where the keys for choosing the codec, bitrate and modes of operation are concentrated. On Xiaomi Redmi 9, access to this partition is hidden by default for the security of the average user.

To activate the hidden menu, you need to do several sequential actions. First go to the basic device settings and find the About phone item, which requires you to find the MIUI version bar and quickly click on it 7-10 times in a row before the notification that you became a developer appears.

Once activated successfully, go back to the main settings menu and go to the Additional (or Advanced Settings) section where a new Developer For option will appear. Inside this section, you need to scroll down to the Network or Bluetooth section. We are interested in the Bluetooth Audio Codec option.

In the list that opens, you'll see the options available to your device, usually SBC, AAC, and possibly aptX if it's supported by firmware, and if the option isn't on the list, it means that the current version of the software or drivers doesn't provide that capability by the standard means.

Once you select the right codec, the system may require you to reconnect the device, make sure the headphones are turned off before you change the setting, and reconnect them after you have applied the settings, ensuring that the handshake process will be run using the new profile.

Using ADB for Forced Activation

If the developer menu doesn’t have the desired codec in the GUI, you can try to access the system directly via the Android Debug Bridge (ADB), a method that allows you to send commands to the system without the limitations of the user interface, but it requires a computer and minimal command line skills.

To start, you need to enable debugging over USB in the same menu For developers. After connecting your smartphone to a PC with the SDK platform set installed, follow the command to check the connection:

adb devices

You can then try changing the global Bluetooth settings through the shell command. However, in modern versions of Android, direct writing to the settings database is often blocked or ignored without root permissions. However, it is worth checking whether the codec system sees at a low level. The command to view current active codecs can look difficult, but there are simplified scripts.

There is also a method of embedding codec libraries into the system partition, but on Redmi 9 without unlocking the bootloader and obtaining SuperUser rights, this is almost impossible. Moreover, interfering with the system libraries of libbluetooth.so can lead to a “boot loop”.

⚠️ Attention: Use ADB-commands to change Bluetooth system settings require accuracy. A syntax error can cause the Bluetooth module to stop running until the phone's settings are completely reset.

If standard ADB commands fail, it confirms that there is no binary support in the kernel, and then further software methods without flashing the device will be ineffective.

Compatibility issues with MediaTek processor

The main obstacle to high-quality sound on Redmi 9 is the processor architecture. MediaTek chips often use their own implementations of the Bluetooth stack, which may differ from the reference implementations of Google or Qualcomm. This leads to the fact that even having a codec on the Android list does not guarantee its stable operation.

The problem is licensing. Qualcomm owns the rights to aptX, and to use this codec, the smartphone maker must pay for a license and implement the corresponding modules in the firmware. In the budget segment, which includes Redmi 9, manufacturers often save on these licenses, limited to open codecs SBC and AAC.

In addition, the bandwidth of the Bluetooth channel on entry-level chips can be limited. Attempting to transmit a high bitrate stream can cause buffering and stuttering of sound.The system automatically lowers the quality to a stable SBC, ignoring the user's settings.

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If the audio is interrupted when selecting high quality, try lowering the bitrate of the transmission or changing the Bluetooth AVRCP mode to an older version, such as 1.4 or 1.5, in the developer menu.

Forum users note that MIUI shells based on Android 10 and 11 for MediaTek devices often saw aptX support cut out even in the driver versions where it was theoretically present, to unify the code and reduce the testing load.

Alternative solutions and equalizers

Since the direct path to enable aptX on Redmi 9 is often a dead end due to hardware limitations, it is worth paying attention to software methods to improve the sound within the available codecs. A well-tuned equalizer can give a more noticeable effect than changing the codec on a mid-range device.

The MIUI equalizer built into the Music app or the Sound and Vibration settings allows you to adjust the frequency response, but for deeper customization, it is better to use third-party applications running through AudioFocus, such as Poweramp Equalizer or Flat Equalizer.

These applications allow:

• 🎚️ Accurately adjust the frequency bands to compensate for the shortcomings of the headphone speakers.
• 🔊 Use the sound virtualization functions and bass boosters.
• 🎼 Create profiles for different genres of music.

It is also worth paying attention to the support of the codec. AAC. On Android devices implementation AAC Often inferior in quality implementation on iOS, but with the right bitrate setting, it can sound better than unstable aptX. AAC, if aptX is not available.

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A quality equalizer setup and a selection of good headphones often give a more noticeable boost to the music enjoyment on Redmi 9 than the race for inaccessible codecs.

FAQ: Frequently Asked Questions