Disabling noise reduction on Xiaomi Redmi Note 9: the full guide

Owners of Xiaomi Redmi Note 9 often face a problem when built-in noise cancellation interferes with normal communication. MIUI algorithms automatically suppress background sounds during calls, voice messages or video recording, but sometimes this leads to voice clipping, distortion of sound or complete "loss" of speech.

Compounding the problem, the Redmi Note 9’s noise-cancelling settings are hidden deep in the menu or not in the standard interface. In this article, we’ll look at all the ways you can disable noise-cancelling, from basic MIUI settings to engineering menus and third-party apps, and learn how to bring back the natural sound of your voice in different scenarios: during calls, when recording videos or using instant messengers.

It’s important to understand that noise cancellation works on three levels: hardware (MediaTek Helio G85 chipset), software (MIUI algorithms) and application (e.g. WhatsApp or Zoom), so there’s no one-size-fits-all solution, you’ll have to test several methods.

📊 Where do you most often face noise reduction problems?
During normal calls
In voicemails
Video recording
In messengers (Telegram, WhatsApp)
In voice chat games

1. Check basic sound settings in MIUI

Before digging deep into the system menus, make sure the problem isn't solved by standard means.The Redmi Note 9 has hidden options that can affect audio processing.

Open Settings → Sound and vibration → Sound quality. Here you can find the following items (depending on the version of MIUI):

  • 🔊 Voice enhancement -- turn off this switch if it's active. It's responsible for automatically correcting voice frequencies, which sometimes leads to artifacts.
  • 🎤 Noise reduction microphone - if such a point is, move the slider to the position "Off.".
  • 📞 Call mode – select “Standard” instead of “Improved".

If you don't have these items on your menu, don't worry, which means your version of MIUI uses hardware noise cancellation, which is controlled at a lower level, so move on to the next section.

Important! After the changes, restart the phone. Some audio settings only apply after the reboot.

💡

If you don't have the right items in your audio settings, try upgrading your MIUI to the latest version. New builds (MIUI 13+) have additional options for controlling your microphone.

2. Disconnecting noise reduction through the engineering menu

The engineering menu (#4636##) allows you to control low-level audio parameters, including noise cancellation, which works on most Xiaomi smartphones with MediaTek chipsets, but requires caution - incorrect settings can worsen the quality of communication.

Step instructions:

  1. Open the Phone app and enter the combination ##4636##.
  2. In the menu, select Hardware testing → Audio.
  3. Scroll down to Noise Suppression (may be called Noise Suppression or NS).
  4. Turn off all switches associated with Noise Reduction, Echo Cancellation and AGC (Automatic Gain Adjustment).
  5. Click "Set" or "Apply" to save.

If the sound quality deteriorates after these manipulations (echoes or background noise), return the settings to their original state, and note that the engineering menu may be reset after rebooting, in which case the procedure will have to be repeated.

What to do if the engineering menu is not opened?
If ##4636### doesn’t work, try an alternative way: install the MTK Engineering Mode app from Google Play. It provides access to the same settings but through the GUI. Once installed, open the Hardware Testing → Audio → Normal Mode section and repeat the steps from the instructions.

3. Noise reduction setting for specific applications

Some messengers and social networks (such as WhatsApp, Telegram, Zoom) have their own noise-canceling algorithms that run on top of the system. They can also be turned off.

Examples for popular applications:

  • 📱 WhatsApp: Open the call → press three points → "Settings" → Turn off Noise Cancelation".
  • 💬 Telegram: During a voice message, tap on the microphone icon → Select "Disable Sound Processing".
  • 🎥 TikTok/Instagram: In the video recording settings, turn off "Sound Improvement" or "Mic auto-setting".
  • 💼 Zoom: Settings → Audio. → Additionally. → Check the box with "Cut down constant noise".

If the app doesn’t have an explicit option to turn off noise cancellation, try using an external microphone (e.g. via USB-C or Bluetooth), in which case Xiaomi’s system algorithms can automatically shut down.

Critical information: In some versions MIUI 14 The noise cancellation in the messengers is forced on at the system level, and to get around this, you have to roll back to an older firmware or use it. ADB-Teams (about this in the next section).

4.Using ADB for deep noise reduction shutdown

If standard methods don't work, you can use ADB (Android Debug Bridge) to change system parameters, which requires a computer and basic command line skills.

Step-by-step:

  1. Turn on USB Debugging on your phone: Settings → About Phone → MIUI Version (click 7 times to become a developer) → Go back to Settings → Additional → For Developers → Enable Debugging.
  2. Connect the Redmi Note 9 to your PC and open the command line (Win + R → cmd).
  3. Enter the commands in turn: adb shell settings put global voice_recognition_service com.android.server.telecom This command resets the voice handler to a standard.
  4. To disable hardware noise reduction (MediaTek only): adb shell setprop persist.audio.fluence.speaker false setprop persist.audio.fluence.voicecall false setprop persist.audio.fluence.voip false
  5. Reboot the phone.

The effect of these commands can be temporary – after updating MIUI settings reset, to fix the changes, you need to repeat the procedure or use Magisk modules (for rooted devices).

☑️ Preparation for ADB-team

Done: 0 / 5

5. Alternative methods: third-party applications and firmware

If none of the above methods worked, radical measures remain: using third-party applications to process sound or flashing the phone.

Popular solutions:

  • 🔧 Microphone Noise Suppression (allows you to manually adjust noise reduction levels) Wo Mic – redirects sound from your phone to your PC, where processing is more flexible.
  • 📱 Brush firmware: Pixel Experience or LineageOS – in them, noise reduction works differently than in the case of the Pixel. MIUI. Firmware on the base AOSP They usually do not have aggressive sound processing algorithms.
  • 🔇 Hardware bypasses: Using an external microphone through USB-C Bluetooth (for example, Boya) BY-M1 Or Rode VideoMic. Connect to a PC via USB Audio Interface (e.g. Focusrite Scarlett).

Note that flashing your phone will void the warranty and may result in data loss.Be sure to back up through Settings → Additional → Backup and Reset before doing so.

⚠️ Note: Some custom firmware (for example, MIUI EU) They have bugs with the sound processing in the microphone. Before installing, check the reviews on the forums. 4PDA XDA-Developers for your model (Redmi Note 9 codenamed merlin).

6. Comparison of methods: what works best?

To make it easier for you to choose the right method, we have compiled data on the effectiveness of each method in a table, based on feedback from Redmi Note 9 users and tests on MIUI 12-14.

MethodEfficiencyDifficultyRisks.Notes
Basic settings of MIUI⭐⭐☆☆☆⭐☆☆☆☆No.It only works on new versions of MIUI.
Engineering menu⭐⭐⭐☆☆⭐⭐☆☆☆It can impair the quality of communication.Resets after rebooting
Application settings⭐⭐⭐⭐☆⭐☆☆☆☆No.It only works for specific messengers.
ADB-team⭐⭐⭐⭐☆⭐⭐⭐☆☆May disrupt the work of system servicesRequires PC and debugging over USB
Custom firmware⭐⭐⭐⭐⭐⭐⭐⭐⭐☆Loss of warranty, risk of "bricking"The most radical but effective method

As you can see from the table, there's no one-size-fits-all solution. If you want a quick call solution, start with the app settings. For streaming or professional audio recording, you'll have to use ADB or custom firmware.

💡

The most reliable method for most users is the combination of switching off noise reduction in the engineering menu. + Customize each messenger separately, and that balances the sound quality with the stability of the phone.

7. Frequent mistakes and how to avoid them

When trying to turn off noise cancellation, many users make common mistakes that only make the problem worse, and the most common ones are:

⚠️ Warning: Never turn off all the audio processing options in the engineering menu at once! This can cause the microphone to be completely inoperable.

Top.-5 mistake:

  • 🔄 Resetting to factory settings without backup is not going to solve the noise cancellation problem, but it will delete all your data.
  • 📱 Use of unoriginal firmware – some “castoms” have microphone bugs that are difficult to fix.
  • 🔊 Disabling all sound effects – this can cause your voice to sound too quiet or distorted.
  • 🔧 Trying to change system files without root is pointless and dangerous.
  • 📡 Ignoring updates MIUI — In new versions, bugs with sound are often corrected.

If you've had a problem after all the manipulations, check the microphone's physical condition, if a clogged or damaged microphone can mimic the effect of noise cancellation, or if you've had a voice message in a quiet room, if the sound is intermittent or nonexistent, you may need repairs.

❓ Why after switching off noise reduction in calls appeared echo?
The echo is caused by the Echo Cancellation off the engineering menu, so to fix this, return the Echo Cancellation setting to "On." and leave the Noise Suppression off. Also check if you're using speakerphone, which echoes more often.
❓ Can noise reduction be disabled for only one application?
Yes, but not for all programs. For example, Zoom or Discord have built-in microphone settings where you can turn off audio processing. For other applications, you'll have to use workarounds: Use an external microphone (via USB-C or Bluetooth); Install SoundAbout, which allows you to redirect sound between sources; you can completely disable noise cancellation for only one application at the system level without root rights.
❓ Why After Updating MIUI noise reduction is back on?
MIUI updates often reset user audio settings, especially if they were changed via an engineering menu or ADB. To avoid this: Before updating, take screenshots of the current audio settings. After updating, reapply all changes (via an engineering menu or ADB). If the problem recurs, consider rolling back on the old version of MIUI or installing custom firmware. In some cases, disabling automatic updates for the Phone and Settings app helps.
❓ Is there a difference between noise reduction in calls and video recording?
Yes, and it's significant: Calls use hardware noise cancellation (processed by the MediaTek Helio G85 chipset), which is difficult to turn off completely. Video recording depends on the camera application. In the standard Mi Camera app, noise cancellation can be turned off in settings (cog icon → "Sound" → "Disable Processing"). Voice messages in messengers are processed at the application level, so their settings are not dependent on the system. For streams (for example, in Twitch or YouTube), it is better to use an external microphone, so you completely circumvent the system restrictions.
❓ Can the shutdown of noise reduction affect autonomy?
Theoretically, yes, but in practice, the difference is minimal. Noise reduction consumes additional CPU resources (MediaTek Helio G85), but turning it off will not increase the autonomy of more than 5-10 minutes with active use. If you notice a significant reduction in operating time, most likely the problem is in another (for example, in the background activity of applications or battery wear). To check the effect on the battery, use the AccuBattery application to monitor the charge consumption before and after changes.