How to check the microphone on Xiaomi Redmi Note 9 Pro: from software tests to physical diagnostics

Xiaomi Redmi Note 9 Pro is one of the most popular mid-range smartphones, but even it is not immune to hardware problems. If your interlocutors complain that they can't hear you when calling, or voice messages are recorded with interference, the first thing to do is check the performance of the microphone. In 80% of cases, the problem is solved by software methods, but sometimes you need physical diagnostics or even repair.

In this article, we will discuss all possible ways to check the microphone on the Redmi Note 9 Pro – from built-in tools. MIUI You will learn how to distinguish a software failure from a hardware malfunction, which applications give the most accurate results, and what to do if the microphone does not work only in certain situations (for example, during video calls or recording video).

Important: The Redmi Note 9 Pro has two microphones — the main one (bottom, for conversations) and the secondary one (top one, for noise cancellation), which have nuances to check, which we will also consider.

1. Quickly check the microphone through the built-in test MIUI

The easiest way to diagnose is to use a hidden hardware test built into firmware. MIUI. It allows you to check all sensors of the smartphone, including microphones, without installing third-party applications.

How to run the test:

1. Open the phone app and dial the combination: ##4636##
2. In the menu that appears, select Hardware Testing (or Hardware Testing).
3. Scroll down to the Audio section and click the Microphone Test.
4. Speak to the microphone, the screen should show a graph of sound waves, and if the line stays flat, the microphone doesn't work.

⚠️ Note: On some versions MIUI This test may not be available, so use an alternative code:

##6484##

If the test shows that the microphone is working but problems persist (for example, people can’t hear you while calling), the reason may lie in:

• 📱 Network settings (problems with VoLTE or 4G-ring-off).
• 🔊 Blower microphone (check if it is covered with a cover or finger).
• 🎤 Problems with a specific application (such as WhatsApp or Telegram).

2. Checking the microphone through voice recording

If the built-in test is unavailable or causes errors, use the standard Dictaphone app (or Record the sound in the audio). MIUI). This method helps to identify problems with sound quality: distortion, noise, low volume.

Instructions:

1. Open the Dictaphone app (if not, install it from Google Play).
2. Press the recording button and speak into the microphone from a distance of 15-20 cm.
3. Play the tape. Pay attention to the video: 🔇 Volume level (too quiet voice is a sign of malfunction). 🎶 Sound purity (wheezing, crackling, or echoes indicate problems). 📶 Background noise (if too much, the top noise reduction microphone does not work).

For more accurate diagnosis, record the sound in different conditions:

💡 Useful advice: If you're recording quietly, try to turn up the microphone volume in the engineering menu:

1. Dial the code: ##36446337##
2. Go to Audio. → Normal Mode → Mic.
3. Increase the Mic Volume by 5-10 units (maximum 255).

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If after increasing the volume in the recording there are distortions, return the settings to place - this is a sign of hardware malfunction of the microphone.

3. Diagnostics through third-party applications

Built-in tools MIUI For deep testing, we recommend using specialized applications that analyze frequency range, noise level and other parameters.

Top.-3 microphone-testing applications:

• 📊 Microphone Test by Keuwlsoft – shows a real-time graph of sound waves, measures decibel levels and frequency.
• 🎙️ Voice Recorder & Audio Editor -- lets you record sound with different bitrate settings and compare quality.
• 🔧 Phone Doctor Plus is a comprehensive test of all sensors in a smartphone, including microphones "Pass/Fail" and recommendations for eliminating problems.

How to check the microphone with the Microphone Test:

Launch the app and allow access to the microphone|

Select the Real-Time Graph mode"|

Speak to the microphone – the graph should respond to the voice|

Switch to "Frequency Analysis" to check the frequency range|

Compare the indicators with the norm (40-60 dB for normal speech)

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⚠️ If the app shows a “Microphone not detected” error, it may mean:

• 🔌 Software failure (reboot the smartphone).
• 🛠️ Damage to microphone plume (disassembly required).
• 📲 Conflict with another application (for example, with a voice assistant).

On the Redmi Note 9 Pro, the top microphone (for noise reduction) often fails after falling or getting moisture. If the app shows only one microphone working, that's fine - the bottom one is used for conversations, and the top one is activated only in noisy conditions.

4. Checking the microphone through a computer (for advanced users)

If you suspect a hardware malfunction, but you want to be 100% sure, you can connect your smartphone to your PC and analyze the sound through an audio editor. USB-cable and software.

What you need:

• 🖥️ Computer with Windows/macOS.
• 🔌 Cable USB Type-C (original, undamaged).
• 🎛️ Audacity (free audio editor).

Step-by-step:

1. Connect Redmi Note 9 Pro to your computer and select File Transfer Mode (MTP).
2. Install Audacity and start the program.
3. In the recording settings (Edit) → Preferences → Select your smartphone as the source of sound.
4. Press the recording button and talk to the microphone, and in real time, the waveform will be displayed on the screen.
5. Stop the recording and analyze it: 📈 Amplitude – if the wave is almost flat, the microphone does not work. 🎵 Frequency spectrum (Analyze tab) → Plot Spectrum – peaks should be in the range of 100-4000 Hz. 🔊 Noises – if you hear clicks or hisses in addition to your voice, the problem is with microphone contacts.

📌 Key Conclusion: If the microphone on the PC is recording sound normally, but the problems persist on the smartphone, the software (firmware, applications) is to blame. If there is no sound on the computer, the microphone itself or its plume is defective.

5. Physical Microphone Check: What Can Be Done Without Disassembly

If software tests show no problems, but the microphone is still not working, it may be mechanical damage or contamination.

🔍 Visual examination:

• 🕳️ Check the microphone hole (located next to the connector) USB-C) for dust, dirt or moisture.
• 🔦 Light up with a flashlight – if corrosion is visible inside, the microphone requires replacement.
• 📏 Make sure the microphone is not pressed (this happens after falls).

🧹 Cleaning the microphone:

1. Turn off your smartphone.
2. Take a toothpick with cotton wool (not metal!) and gently clean the microphone hole.
3. Use a spray of compressed air (for example, to clean keyboards) to blow out dust.
4. ❌ Don't use alcohol or liquids! it can damage the microphone membrane.

🔄 Post-cleaning test:

Turn on your smartphone and check the microphone through the recorder. If the sound became clearer, the problem was pollution. If there was no change, the plume contacts may have gone away (disassembly required).

⚠️ Attention: On the Redmi Note 9 Pro, the top microphone (for noise reduction) is located next to the headphone jack, and contamination often leads to people hearing echoes or wind noise. Clear both microphones!

6.Diagnostics of microphone problems in specific applications

Sometimes the microphone works in some programs (for example, in a voice recorder) but does not work in others (WhatsApp, Zoom, games), this indicates a conflict of permissions or settings of a particular application.

📱 Problems in messengers (WhatsApp, Telegram, Viber):

• 🔄 Restart the application and give it access to the microphone (Settings) → Annexes → Permits).
• 📱 Check your voice message settings: go to WhatsApp ⋮ → Settings → Warehouse and data → Voice Messages and Select Quality "Best".
• 🔄 Update the messenger to the latest version.

🎮 Problems in games (PUBG, Free Fire, Call of Duty):

• 🎤 In the game settings, turn off and turn on voice chat again.
• 🔊 Check if the microphone is turned off in the system sound settings (Settings) → Sound. → Microphone).
• 📱 Install the Game Turbo app (included in the Game Turbo app) MIUI) and turn on the "Game Voice Chat" mode".

💻 Problems in Zoom/Skype/Google Meet:

• 🔄 Close all background apps that use the microphone (such as voice assistants) before calling).
• 🎤 In conference settings, select Xiaomi Redmi Note 9 Pro Mic as input device.
• 📶 If the problem is only on mobile Internet, switch to Wi-Fi – some applications limit the sound quality when the signal is weak.

🔍 How to identify application conflict:

1. Go to Settings → Applications → Permissions → Microphone.
2. Sort the applications by the date of last use.
3. Turn off microphone access for all applications except system ones.
4. Turn on permissions and check after which application the microphone stops working.

7. When to contact the service: signs of hardware malfunction

If all of the above methods didn’t work, it’s probably a hardware problem, and here are some indications that the microphone on the Redmi Note 9 Pro needs repair:

• 🔇 The microphone does not work in all applications, including the built-in voice recorder.
• 📉 The sound level in the tests shows 0 dB (complete absence of signal).
• 🔌 After falling or getting moisture, the microphone stopped working (even after drying).
• 🎛️ When talking, the interlocutors hear metal ringing or severe interference.
• 🔧 In the engineering menu (#4636##) the microphone is displayed as "Not connected".

🛠️ What exactly could be wrong:

⚠️ Attention: On the Redmi Note 9 Pro, the top microphone (for noise reduction) often fails after moisture enters the headphone jack. If you drop your phone in water, don't dry it with a hair dryer or battery, it will accelerate corrosion.

🔧 How to choose a service center:

• 🏆 Preference is given to authorized Xiaomi services (list on the Mi Service website).
• 💰 Compare prices: In informal workshops, repairs can be cheaper, but without warranty.
• ⏱️ Replace the microphone usually takes 1-2 hours, but if the plume is damaged, it can take up to 3 days.

8.Prevention: How to prolong the life of the microphone on the Redmi Note 9 Pro

To avoid future microphone problems, follow these guidelines:

🛡️ Protection against moisture and dust:

• 🌧️ Do not use your phone in the rain or in the bathroom (even if it has protection). IP53, It will not save you from direct water intake).
• 🧴 Apply a hydrophobic coating (e.g., Nano-Coating) once every 6 months.
• 🧹 Regularly clean the microphone holes with a soft brush.

📵 Protection against mechanical damage:

• 📱 Use a case with reinforced bumpers (for example, Spigen Tough Armor).
• 🚫 Avoid falling on hard surfaces - even from a height of 50 cm, the microphone plume can come off.
• 🔌 Carefully insert the charger so as not to damage the connector USB-C (near-microphone).

⚡ Programme prevention:

• 🔄 Update regularly MIUI — In new versions, bugs related to the microphone work are corrected.
• 📱 Do not install apps from unknown sources – they may conflict with audio drivers.
• 🎤 Before important calls, reboot your phone – this resets temporary audio system errors.

💡 Useful Lifehack: If you make frequent calls in noisy places, turn on the “Enhance Voice” option in your call settings (Settings) → Calls. → Voice enhancement. This activates the second noise-cancellation microphone and improves communication quality.

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Regular cleaning of microphones and avoiding mechanical damage extends their service life by 2-3 times, and most malfunctions are caused by dust or moisture, not by equipment aging.

FAQ: Frequent questions about the Redmi Note microphone 9 Pro