Many Xiaomi and Redmi smartphone owners experience the annoying effect of holding the phone to their ears, where a loud, piercing squeak or hum is heard in the speaker, a phenomenon known in technical documentation as a back talk or local tone, designed to confirm that the microphone is working and transmitting your voice.
However, in poor communication or when using certain accessories, this feature becomes not an assistant, but a hindrance, creating strong feedback and interfering with the interlocutor. Standard audio settings often do not give direct access to completely disabling this setting, requiring a deeper dive into the engineering menu or customizing special features.
In this article, we will explore proven methods for eliminating the feedback effect on devices with a shell MIUI and HyperOS. You will learn to adjust the sensitivity of the microphone and adjust the noise cancellation so that conversations become comfortable and sound is clean and devoid of foreign artifacts.
What is the Back Talk Effect and Why Does It Happen?
Back talk (or sidetone) is a feature that allows a speaker to hear their own voice in a handset with a small delay, originally introduced into landlines so that the subscriber does not shout into the phone, thinking that communication is interrupted. In modern Xiaomi smartphones, this algorithm is also present, but its implementation sometimes leads to acoustic discomfort.
The main reason for this effect is because of noise reduction and automatic volume control algorithms, and when the noise reduction system is not working properly or the microphone is closed with a cover, the phone can amplify the incoming signal, creating a feedback loop, especially in quiet rooms or when using headsets.
It’s worth noting that on some models, such as the Redmi Note or the budget Poco series, the microphone can be calibrated from the factory with a focus on maximum audibility, ignoring user comfort, in which case the software artificially ups the local tone level, which is perceived as an unpleasant whistle.
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If the feedback effect appeared suddenly after the system update, try resetting the phone application settings in the application management menu without deleting the contact data.
Basic volume and sound setting in MIUI
Before we go to complex engineering codes, we need to eliminate the commonplace software failures in the multimedia settings. Often users accidentally activate modes that amplify certain frequencies, which provokes echoes. Checking the basic parameters is the first step to solving the problem.
Go to Settings → Sound and Vibration, and you're not only interested in the overall volume, but also the extra settings hidden in the Sound Quality or Mi Sound Enhancer menu. Turning off any surround sound effects can reduce the likelihood of artifacts occurring during a conversation.
It is also important to check the settings of the specific MIUI Dialer application. In some versions of the firmware inside the ringer, there is a separate volume slider (Ear) that adjusts the sound level during a conversation, and its reduction to a comfortable minimum often removes the whistle effect.
- 🔊 Open the Sound and Vibration menu and make sure the Sound Improvement mode is turned off.
- 📞 Press the menu button during the call and check if the hands-free mode or Bluetooth amplifier is on.
- 🔇 Make sure that the Notifications settings do not have the maximum volume that can resonate with the voice.
☑️ Diagnostics of sound settings
Using an engineering menu to turn off tone
The most effective way to control communication parameters is to enter the engineering menu through special USSD-This interface allows you to access hidden settings of the radio module, including the sensitivity of the microphone and the local tone level (sidetone.
To enter the engineer menu, most Xiaomi devices use the code ##6484## or #4636##. Once you enter the combination, you will open a list of tests. You will need to find the section related to Phone Information or Hardware Testing. Depending on the processor model (Snapdragon or MediaTek), the item names may differ.
Inside the menu, look for the Audio tab, where you can find the SideTone or Local Tone, which is usually set to 1 (on), switching to 0 (off) completely disables your voice from the speaker, and this is the only software way to completely remove the back talk at the system level, bypassing the standard interface constraints.
⚠️ Note: In the engineering menu, do not change the values of the parameters, the name of which you are not sure. Resetting the wrong settings of the radio module can lead to loss of signal or inability to make calls.
If the standard codes don't work (the operator blocks them), you can use the Activity Launcher app from Google Play, find the CIT or Engineering Mode activity in the list and run it, which will allow you to get into the same menu without entering the codes.
What to do if the engineering menu is empty?
Setting up noise reduction and microphone
Xiaomi’s current smartphones are equipped with two or more microphones to implement Active Noise Cancellation (ANC) technology. One microphone takes voice and the other cuts off background noise. If the algorithm is aggressive, it can cut frequencies to create a zippering effect or, conversely, amplify feedback.
Check the physical condition of the microphones. The bottom hole is often clogged with dust or pile from your pocket, which distorts the sound. The top microphone, which is responsible for noise reduction, also requires cleanliness. Using a tight cover that covers the holes is guaranteed to cause whistles and echoes.
Some HyperOS firmware has a voice enhancement feature that processes sound software, and try turning it off in the feature settings or in the audio menu, which will reduce the workload on the processor and can remove the processing artifacts in real time.
- 🧹 Carefully clean the microphone holes with a soft brush, without using sharp objects.
- 📱 Remove the protective case during the call to check if it is the cause of the resonance.
- 🎤 In the special features settings, turn off “Improving speech intelligibility” if this option is active.
Problems with Bluetooth headsets and speakers
If the back talk effect is only manifested when you connect a Mi True Wireless headset or third-party headphones, the problem may lie in the data protocol. Cheap codecs or interference in the air cause a signal delay, and the phone, without receiving confirmation, raises the volume, creating a feedback loop.
Try turning off the "Absolute Volume Level" option in Bluetooth settings, which will separate the volume control of the phone and the headphones, which often helps synchronize signal levels and remove the whistle, and forget the device in the paired list and reconnect it.
When using Android Auto automotive systems or built-in Bluetooth car systems, set up Echo Cancellation (AEC) If you have an old tape recorder in the car, it may not be able to quench the echo, and the only solution is to turn the volume down or use the car's speakers. AUX-cable.
| Type of connection | Possible cause of echoes | Method of decision |
|---|---|---|
| Bluetooth headphones | Codec delay/interference | Turn off absolute volume. |
| Wired headset | Bad plug contact | Clean the 3.5mm/USB-C connector |
| High-profile communication | reflection of sound from surfaces | Change the position of the phone / Reduce the volume |
| Car | AEC Systems Conflict | Use AUX or lower the volume of the car |
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Bluetooth echo problems are often solved by reconnecting the device or disabling the Absolute Volume Level feature in the developer menu or Bluetooth settings.
Additional methods and resetting settings
If software manipulations have not helped, it is possible that a third-party application with access to the microphone may cause the conflict. Recorders, voice assistants or instant messengers can intercept the audio stream. Check the permission list in the Settings section → Security and Security → Data access and restrict the rights for suspicious programs.
A radical but effective method is to reset your network settings, which won't delete your personal photos or contacts, but will return all the parameters of your communication, including your settings. APN And Bluetooth, to factory values. → Connection and sharing → Reset Wi-Fi, mobile networks and Bluetooth.
In extreme cases, when the problem is observed on all devices of the same model, we can talk about a software bug of a particular version of MIUI. In this situation, you should wait for the system update or, for advanced users, consider installing a global version of the firmware, where the sound calibration may differ from the Chinese one.
⚠️ Note: Resetting your network settings will require re-entering passwords from Wi-Fi networks and re-pairing Bluetooth devices. Make sure you remember the necessary passwords before performing this operation.