Why you can’t hear the interlocutor in the phone Xiaomi Redmi 9 when calling – a complete analysis of the problem

You call Xiaomi Redmi 9, but you can't hear the other person at all — or is his voice barely distinguishable, interrupted, accompanied by wheezing? The problem is familiar to many owners of this model, and there may be more than a dozen reasons for it. From the banal clogging of the speaker to serious hardware breakdowns. In this article, we will analyze all possible scenarios why the sound in the phone disappeared during calls, and give clear instructions on how to restore the phone to work.

It’s important to understand that Redmi 9 (including Redmi 9A/9C/9T) is a budget smartphone with characteristic sound system diseases, some of which are solved in 5 minutes at home, others require the intervention of a service center, and we will help you determine what exactly you are facing and what to do next.

1. Checking basic settings: is the sound off by accident?

Start with the obvious: it's possible that the sound on the calls is software-enabled. Redmi 9 has a few places where this could have happened.

One is Do Not Disturb Mode or Quiet profile.

• 📱 Open the Settings. → Sound and vibration → Don't disturb.Make sure the mode is off or set to skip calls.
• 🔔 In the notification curtain (swipe down), check if the “Silent Mode” icon is activated** (bell with crossed speaker).
• 🎧 If you use a headset, turn it off – sometimes the phone forgets to switch back to the speaker.

The second is customized volume settings. On Redmi 9, the volume of the call and the media are adjusted separately. During the call, press the volume buttons and make sure the slider is not at zero. If there is a sound but very quiet, try to increase the volume through the engineering menu (more on this below).

2. clogging or damage to the speaker

In 70 percent of cases, the problem with the sound in the handset on the Redmi 9 is due to physical clogging or wear of the speaker, which is located at the top of the phone (near the front camera) and over time gets clogged with dust, pocket pile or cosmetics. Unlike the main speaker (bottom), the conversational speaker is not protected by a grid, so it is vulnerable to contamination.

How to check:

• 🔍 Take a flashlight and shine a speaker through the hole?
• 🎵 Turn on voice recording and hold the phone to your ear – if the sound is recorded but not played in the speaker, the problem is precisely in it.
• 📱 Call another phone and put your finger on the speaker, and if you have vibrations, but no sound, the speaker is clogged or malfunctioning.

How to clean:

1. Turn off the phone.
2. Take a toothpick with cotton wool (or soft brush) and carefully remove visible contaminants. Do not use metal objects!
3. For deep cleaning, use a compressed air can (sold in electronics stores) and hold the balloon vertically so as not to damage the speaker membrane.

⚠️ Attention: Do not blow into the speaker with your mouth - moisture from the breath can oxidize the contacts. Do not use wet wipes or alcohol - they dissolve the glue that holds the speaker.

3. Firmware problems or software failures

Software failures are the second most common cause of loss of sound, especially for Redmi 9 after MIUI updates or custom firmware installations.

• The sound is only lost during calls, but it works in music/video.
• The problem arose after the system was updated.
• The phone "gluts": spontaneously reboots, brakes.

Decisions:

1. Reset audio settings: ##36446337## Enter this code in the Phone app as if dialing a number. The test menu will open. Select Audio → Normal Mode → Receiver and check if there is sound.
2. Cache Clearing: Go to Settings → Applications → App Management → Phone, click Clear Cache.
3. Reset all settings: If the problem persists, reset to factory settings (Settings → About Phone → Reset). Remember to save the data!

If the crash happened after the MIUI update, try to roll back to the previous version via Fastboot or wait for a patch from Xiaomi. Check the forums (for example, 4PDA), the problem may be massive and there is a solution already.

Check the sound in the engineering menu|Clear the cache of the "Phone" application"|Remove the latest updates (if the problem has occurred after them)|Reset the sound settings to factory-->

4. Failure of the plume or contacts dynamics

The speaker in Redmi 9 is connected to the motherboard through a flexible plume, and over time, the contacts oxidize, the plume rubs or moves away from the connector, which leads to:

• Periodic loss of sound (i.e., no).
• Wheezing or distortion of the interlocutor’s voice.
• Completely no sound, even if the speaker is in good working order.

How to diagnose:

• 📱 Carefully press the top of the phone (above the speaker) during the call. If the sound appears, the problem is contacts.
• 🔧 Put a flashlight in the gap between the screen and the body, and if you see a plume inflection, it's damaged.

The solution is just to take down the phone and:

• Reconnect the plume (if it has moved away).
• Replacement of the plume (cost - from 400 rubles).
• Cleaning contacts with alcohol (if they are oxidized).

⚠️ Warning: Don't try to disassemble the Redmi 9 yourself if you don't have experience.The plume of the speakers is fragile and the screen is glued - there is a high risk of damaging the phone.

5. Problems with SIM-card

Sometimes the sound is not lost because of the phone, but because of:

• 📶 In areas of low coverage, the voice may be interrupted or become indistinct.
• 🔄 Failures at the operator, for example, when the network is congested or technical work.
• 💳 Faulty. SIM-If the card contacts are contaminated or damaged, the phone may not handle calls correctly.

How to check:

1. Call your number from another phone, and if the problem recurs, it's the carrier's fault or the SIM.
2. Try inserting the SIM into another phone. If there's sound, there's a problem with Redmi 9.
3. Clear the contacts. SIM-Cards with a scrub (carefully!) and reboot your phone.

If there's a problem with the network:

• Switch to another communication standard: Settings → SIM-maps and mobile networks → The preferred type of network. 4G/3G/2G (a) by car or by force Only 3G.
• Activate VoLTE (voice over 4G) if your carrier supports this feature, which improves the quality of communication.

6.The impact of third-party applications and viruses

Some applications (especially SEOs, antiviruses, or call recording software) can block sound during a conversation, and viruses or adware sometimes interfere with the phone module.

How to check:

• 🔍 Launch your phone in Safe Mode (press the power button) → «Safe Mode. If the sound appears, the third-party app is to blame.
• 📱 Check the application permissions: Settings → Annexes → Permits → Microphone/Phone: Remove suspicious programs.
• 🛡️ Scan your phone for viruses (for example, through Malwarebytes or built-in Security). MIUI).

Frequent culprits:

• 🎤 Call Recorder Applications (Cube Call Recorder, ACR).
• 🔊 Battery Optimizers That Disable "Background" Processes.
• 📱 Launchers from third-party developers (for example, Nova Launcher sometimes conflicts with the new platform). MIUI).

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If the problem occurs after you install a new app, delete it and restart the phone, often to help you get the sound back.

7 Hardware breakdowns: what else could have broken?

If all previous methods have failed, the problem is likely hardware. Redmi 9 most often fails:

• 🔊 Audio codec is a chip that handles sound processing, and when it breaks, the sound disappears completely (in speakers, headphones, microphones).
• 📡 Antenna module – if the phone fell or got wet, the contacts of the communication module could oxidize.
• 🔋 Power controller – in the event of unstable voltage, some components (including the speaker) may be turned off.

Diagnostics of hardware problems require special equipment.

If the phone was in a wet environment (like a bathtub) or fell into the water, even if everything was dry, the contacts could have oxidized inside, requiring complete disassembly and cleaning with alcohol.

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If the sound is lost after a phone drop, mechanical impact or contact with a liquid, there is a 99% chance of hardware failure.

FAQ: Frequent questions about sound at Redmi 9