Dims the screen and quiet sound in WhatsApp on Xiaomi: causes and solutions

When the screen suddenly goes out while listening to a voice message in the popular WhatsApp messenger on a Xiaomi smartphone, and the sound becomes barely distinguishable, this is not an accidental system failure, but the regular operation of the proximity sensor, which mistakenly interprets your actions as bringing your phone to your ear, at which point the device goes into “talk” mode, blocking the display and switching the audio stream to the upper conversational speaker, which is much quieter than the main multimedia.

Understanding the mechanics of this process is key to solving the problem quickly. The proximity sensor located at the top of the case responds to any objects in the immediate vicinity, whether it is a finger, the edge of a case or even contamination on the protective glass. The MIUI system installed on Xiaomi devices sometimes over-calibrates this sensor too aggressively, leading to false positives even when the smartphone is horizontally positioned in the hands.

In this article, we will discuss the physical and software causes of this behavior in detail, and provide step-by-step instructions for troubleshooting. You will learn how to properly adjust the sensitivity of the sensor, clean up hidden contamination, and what Android system settings can conflict with the work of the messenger. Ignoring this problem can lead to accidental pressing of buttons by the screen in your pocket or skipping important parts of audio messages.

Mechanics of the approximation sensor and speakers

The main reason why the screen goes out is to activate the talk mode. When you click on audio playback on WhatsApp, the app defaults to using the system audio channel for calls, not the multimedia channel. This is done so that the user can listen to messages while holding the phone to his ear like a regular tube. However, if the approximation sensor is closed, the phone "thinks" that it is already in the ear, and locks the screen to save energy and prevent false touches with the cheek.

Sound becomes quieter because of the audio switching. In normal video or music mode, sound is played through a lower multimedia speaker, which has high power and rich sound. In ear mode, the sound is redirected to the upper earpiece speaker, whose task is to transmit the speaker's speech, rather than play audio files with high quality, which is why voice messages in this mode sound deaf and quiet.

⚠️ Attention: Constant operation in the “conversation” mode with a closed sensor can lead to overheating of the upper part of the smartphone body, since the speaker works in an abnormal for long-term playback mode.

Often users don't realize that even a transparent protective film, skewed, can completely block the infrared radiation of the sensor. In Xiaomi devices with a cut-out drop or bang, the sensor is often hidden under a thin layer of metal or plastic, and any additional obstacle disrupts its operation, which leads to the screen going out immediately after playback, not allowing you to look at the timer or text of the message.

Physical obstructions and sensor contamination

The first thing to check when a problem occurs is the physical condition of the top of the screen, and even a microscopic layer of fat, dust, or villi from your pocket can cause an infrared sensor to falsely act, and the sensor works by emitting and receiving a reflected signal: if the signal is reflected off the dirt immediately, the system picks up the object up close.

Special attention should be paid to protective accessories. Many users buy cheap protective glasses that do not have special cutouts for Xiaomi sensors. In such cases, the glass acts as an opaque curtain, and massive cases with high sides can also cause problems, which, when tightly attached to the body, partially block the area of operation of the sensor.

To diagnose physical problems, follow the following steps:

• 🧼 Carefully wipe the top of the screen with a microfiber, paying attention to the area above the speaker.
• 📱 Remove the protective glass or film and check if the problem persists without them.
• 🔍 Inspect the case for overhanging edges above the sensor area.

If the problem persists after cleaning, it's probably due to software calibration or the settings of the application itself, but you can't ignore the physical factor, because even high-quality glass can eventually unstuck in the sensor area, creating an air cushion that distorts the readings.

Software calibration of the sensor in MIUI

In the MIUI shell and its new version of HyperOS, there is a hidden engineering menu for testing and calibrating hardware components. If the proximity sensor is malfunctioning due to a software failure, it can be reconfigured. This often helps if the screen goes out spontaneously for no apparent physical reason.

To enter the engineering menu, open the Phone app and enter the code ##6484##. The CIT menu will open before you. In the test list, look for the Proximity sensor. When you click on it, you will see the current sensor readings. In the normal state, when nothing is closing the top of the screen, the value should be 5.0 or 0 (depending on the firmware version), and when you close the top with your hand, change to the opposite.

If the values don't change or change randomly, try pressing the Calibrate button on this menu. It takes a few seconds. Once you've successfully calibrated, the phone may suggest a reboot. This action resets the sensor's software sensitivity thresholds and often fixes the fading screen problem.

⚠️ Note: Do not change other options in the engineering menu CIT, If you are not sure about their purpose, resetting the calibration of other sensors (for example, an accelerometer) can lead to improper operation of the autorotation of the screen or navigation.

WhatsApp App and System Settings

Sometimes the problem isn't with the phone, but with how the app handles audio. Recent versions of WhatsApp have introduced a feature that allows you to switch audio channels manually, but it can run unstable on Xiaomi.

Try changing the settings inside the messenger itself. Go to Settings → Chats and find Listen Mode (if available in your version). However, a more effective method is to change the behavior of the system when playing. Some users note that disabling the “Revenge Volume in Your Pocket” or similar options in the MIUI audio settings helps stabilize the work.

Also, check the app's permissions. Go to Settings → Apps → All apps → WhatsApp → Permissions. Make sure the app has access to the microphone and, if there is one, to the sensors. Sometimes resetting permissions (the Reset button at the bottom of the permissions screen) helps resolve software conflicts.

Use of third-party applications and mods

If the standard methods don't work, specialized utilities come to the rescue. There are many applications in the Play Market, such as Proximity Sensor Reset & Fix or Lesser AudioSwitch, that force audio channels to be controlled and ignore app-specific proximity sensor signals.

One effective solution is an app that forces WhatsApp to use a media channel instead of a call channel, where you have to find your phone on the list and for WhatsApp to select a profile of "Media" or "Speaker," which software disables the switch to the top speaker, and the screen stops going out because the system does not go into talk mode.

However, it is worth remembering that installing third-party software requires care. download applications only from trusted sources. Some “optimizers” may contain ads or miners, which will negatively affect the performance of your Xiaomi.

System conflicts and software updates

The problem can be caused by a bug in a particular version of the Android operating system or the MIUI shell. Often these bugs are fixed in security patches. Check for updates in the Settings menu → About Phone → MIUI version.

Other applications that use the proximity sensor (e.g., smart cases, control gestures, call blockers) may also conflict. Try to start the phone in Safe Mode. To do this, press the off button and select the appropriate item (or press the off button when booting, depending on the model). If the problem is gone in Safe Mode, then the third-party application is to blame.

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Before a global settings reset, try removing the WhatsApp app cache through the app management menu, which often solves the problem without losing correspondence.

In rare cases, a complete reset of your phone's settings helps, but before you do that, make sure to back up your data, which is an extreme measure that eliminates any software errors that have accumulated during your smartphone use.

Frequently Asked Questions (FAQ)

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In 80% of cases, the problem is solved by removing the protective glass or cleaning the top of the screen from contamination, as the proximity sensor is extremely sensitive to any obstacles.