How to increase the volume of Bluetooth headphones on Xiaomi Redmi 9T: from standard settings to hidden features

Wireless headphones on Xiaomi Redmi 9T often sound quieter than wired ones, a common problem with Bluetooth protocol limitations and MIUI security policies. Even at maximum player volume or system settings, sound may not be powerful enough, especially in noisy conditions. In this article, we will discuss all possible ways to increase volume, from basic settings to hidden parameters of the engineering menu and third-party utilities.

It's important to understand that quiet sound is not always hardware-related, and it's often the software limits that the manufacturer sets to protect users' hearing or to comply with the EU Volume Limit standards. But these limits can be bypassed — legally and without harm to the device. We tested all methods on Redmi 9T with MIUI 12.5 and MIUI 13 firmware, so the instructions are relevant for most versions of the system.

1. Checking basic volume settings

Before resorting to radical methods, make sure the problem isn't in the obvious settings.On the Redmi 9T, the volume of Bluetooth headphones is adjusted separately from the phone's speakers, and many users miss this point.

Open the Quick Settings Panel (swipe down from the top edge of the screen) and check the volume slider. If a Bluetooth icon is displayed next to the speaker icon, you adjust the volume of the headphones. If there is no icon, tap down the arrow next to the slider and select the Bluetooth Device in the list.

• 🔊 Separate adjustment: In some applications (e.g. YouTube or Spotify), volume is controlled independently of the system.
• 🎧 Bluetooth Profile: Make sure the headphones are connected in mode A2DP (for music, not HFP (The latter limits the volume of calls.
• 🔄 Reconnect: Sometimes helps to disable and reconnect the headphones through Settings → Bluetooth.

If the sound remains quiet after this manipulation, move on to the following methods. On Redmi 9T with MIUI 13+ firmware, Bluetooth settings reset can work: go to Settings → System → Settings Reset → Network settings reset and select Bluetooth Reset.

2. disable volume limit in MIUI settings

Xiaomi defaults to activate the maximum volume limit to protect hearing, called "Safe Volume," and can reduce the sound level to 80 percent of its maximum.

1. Go to Settings. → Sound and vibration.
2. Slip on Safe Volume and Timer.
3. Turn off the Safe Volume switch.
4. Confirm the action by moving the slider on the warning screen.

When you turn off, check the volume, the difference can be as high as 20-30%, and if you don't have Safe Volume in your firmware, the limit is already disabled or a different version of MIUI is being used.

⚠️ Warning: Long-term listening to music at maximum volume (above 85 dB) can lead to irreversible hearing loss.

Check the current version of MIUI in Settings → About the phone

Backup settings through Settings → Additional → Backup

Make sure the headphones are charged and connected stably

Disable energy saving modes (Settings → Battery → Energy saving mode)

-->

3.Use of the Engineering Menu (MTK Engineering Mode)

The Redmi 9T has a Qualcomm Snapdragon 662 processor, but the engineering menu method works on it thanks to universal Bluetooth settings, which allows you to increase the volume at the hardware level, bypassing the limitations of MIUI.

Instructions:

1. Open the Phone app and type the combination: ##36446337## (or alternative code ##4636## if the first one didn't work).
2. Choose Hardware Testing → Audio.
3. In the Bluetooth section, find the Max Vol or Volume settings.
4. Set your Media (music) and Voice Call (calls) values to a maximum (usually 150 or 160).
5. Save the settings and restart the phone.

If the engineering menu doesn't open, your firmware will block access, and installing the MTK Engineering Mode app from Google Play (which doesn't work on all devices) will help.

4. Third-party applications for sound amplification

If standard methods don't work, we'll have specialized tools to help, and they work on two principles: either amplify the sound programmatically (via equalizer), or modify the system parameters. We tested 5 applications on Redmi 9T, and the best results were:

To start, try the Bluetooth Volume Booster, which doesn't require root and specializes in wireless devices.

1. Put the headphones on.
2. Launch the app and move the Boost Level slider 100%.
3. Activate the Apply on Boot option to save the settings after the reboot.

⚠️ Attention: Annexes of type ViPER4Android Can conflict with system sound drivers MIUI. If after installation there are wheezing or the sound disappears - remove the utility and use alternative methods.

💡

Before installing third-party utilities, check Redmi 9T user reviews on Google Play. Some apps are optimized for specific models and may not work on your device.

5. editing system files (for advanced users)

This method requires root rights and is designed for power users. It involves editing a file. mixer_paths.xml, The one that controls volume limits at the hardware level. 9T file is on its way /vendor/etc/mixer_paths_qrd_skuh.xml — It needs to be modified with a root-access file manager (e.g., Root Explorer).

Instructions:

1. Make a backup copy of the original file.
2. Open the file in the text editor and find the lines with the parameters: <path name="bluetooth-sco"> <ctl name="RX1 Digital Volume" value="84" /> <ctl name="RX2 Digital Volume" value="84" />
3. Increase the value to 92 (maximum for most devices).
4. Save the file, restart the phone and check the volume.

If the changes cause the sound to become distorted or interfere, return the original values, which is the most volume-boosting method, but can also damage the system files.

💡

Editing system files is the most effective way to turn up the volume, but it's also the most dangerous. Without backup and root knowledge, you run the risk of getting a brick instead of a phone.

6. Alternative solutions: from hardware to software

If none of these methods worked, consider alternative options:

• 🔌 Use of external amplifier: Bluetooth amplifiers (e.g. FiiO) BTR3) connect to headphones and increase the signal power without changing the phone settings.
• 🎛️ Equalizer setting: B MIUI There is a built-in equalizer (Settings) → Sound. → Equator: Low and medium frequency increases volume subjectively.
• 🔄 Reset to factory settings: In rare cases, the problem lies in a conflict of system files. Reset via Settings → The phone. → Resetting settings can help.
• 📱 Update of the firmware: In new versions MIUI Sometimes they fix sound bugs. Check the Settings update. → The phone. → Updating the system.

If you use headphones that support aptX or LDAC codecs, make sure they are activated. These codecs provide better sound quality and sometimes greater volume.

1. Put the headphones on.
2. Go to Settings → Connected devices → Settings gear next to the headphones.
3. Select Sound Quality and install LDAC or aptX.

FAQ: Frequent questions about Bluetooth volume increase on Redmi 9T