Why is the Xiaomi Redmi 9’s microphone not working properly?
The microphone in Xiaomi Redmi 9 is a key element for calls, voice messages and audio recording. But many users face problems: the interlocutor does not hear well, the recording is accompanied by noises, and voice assistants do not recognize commands, the reasons are several: from banal contamination of the connector to failures in the firmware.
In this article, we'll look at all the ways you can tune a microphone, from basic checks to fine adjustments in the engineering menu, how to check performance, eliminate interference, and optimize sensitivity for specific tasks (calls, streams, dictation), and if the microphone doesn't work at all, you'll find instructions for diagnosing hardware malfunctions.
Important: the settings may vary slightly depending on the MIUI version (global, Chinese, European).We focus on the latest stable firmware for Redmi 9 (Android 10/11 with MIUI 12.5+), but we will provide alternative paths for other versions.
Basic microphone check before setting up
Before you dig into the settings, make sure the problem isn't hardware. Here's the minimum checklist:
🔍 Check the physical cleanness of the connectors (3.5 mm, USB-C, microphonehole)
📱 Make sure there is no mechanical damage to the body near the microphone
🔊 Test the microphone in different applications (calls, voice recorder, WhatsApp)
🔄 Reboot your phone (sometimes helps with temporary driver crashes)-->
If you don't get the microphone working, you can move on to the next section, and if it works but it doesn't work, you can read more about optimization.
⚠️ Attention: Do not use sharp objects to clean the microphone hole! This can damage the membrane. Better use a soft brush or compressed air (a canister for cleaning equipment).
Customization of microphone sensitivity in standard parameters
Xiaomi Redmi 9 allows you to adjust the sound recording level through system settings.
- Open the Settings. → Sound and vibration.
- Scroll down and select Sound Quality (some firmware may call it Sound Improvement).
- Activate the microphone boost slider (if available) or select High Sensitivity profile.
For calls, check further:
- 📞 Settings → SIM-maps and mobile networks → Call settings → Improved voice (include if available).
- 🔇 Settings → Special facilities → Improvement of sound → Noise suppression (turn off if voice sounds timid).
Phone calls
Voice messages in messengers
Video/stream recording
Voice search and assistants
Other-->
If standard settings are not enough, move on to advanced methods in the next section.
Advanced settings through the engineering menu (for experienced)
Xiaomi’s engineering menu gives you access to hidden microphone settings, but you need to be careful. Incorrect changes can lead to sound crashes – write down the original values before editing!
To open the menu:
- In the phone app, type the combination: ##4636##.
- Select Phone Information (or Hardware Testing in Global Firmware).
- Scroll to the Audio section and tap the Microphone.
Here you will see the current signal levels for each microphone (main and secondary for noise reduction).
| Parameter | Normal value (dB) | Deviation action |
|---|---|---|
| Level 0 (silence) | -85...-70 | If it is above -60 dB, check the microphone for contamination. |
| Level 1 (common speech) | -50...-30 | If below -55 dB, increase the gain in the settings. |
| Max Level (max volume) | -10...0 | If not, the microphone may fail. |
⚠️ Note: In the engineering menu, do not change the Mic Gain and Noise Suppression settings unnecessarily. Incorrect values can cause audio distortion or a complete microphone shutdown.
What to do if the engineering menu does not open?
Optimizing the microphone for specific applications
Different programs use the microphone differently, and here's how to set it up for popular scenarios:
1. Calls (standard phone/WhatsApp/Telegram)
- 📱 In Call Settings, turn off Echo Suppression – this often improves legibility.
- 🔊 On WhatsApp: Settings → Warehouse and data → Quality of voice calls → Prefer quality.
- 🎤 For Telegram: Enable High Voice Quality in Call Settings.
2. video recording (TikTok, Instagram, camera)
- 🎥 In a standard Xiaomi camera, select Settings → Video quality → High (Full) HD) — This automatically optimizes the audio track.
- 🎤 For TikTok: Before recording, click on the microphone icon and select the External microphone (even if only the built-in microphone is connected).
- 🔇 Use headphones with a microphone for better noise reduction.
3. Voice assistants (Google Assistant, Alice)
- 🤖 For Google Assistant: Settings → Voice Match. → Re-tuning the voice.
- 🗣️ For Alice: Say "Setting up voice" and follow the instructions.
- 📱 Turn on Permanent listening in the assistant settings (battery discharge will increase!).
Solving Common Problems with the Microphone
If the microphone is not working properly, here is the diagnostic algorithm:
| Problem. | Possible cause | Decision |
|---|---|---|
| The interviewer can't hear you. | Main microphone is disabled | Check Settings → Sound → Microphone → Main microphone (must be on) |
| Severe noise/interference | Noise suppression activated | Turn off noise suppression in special features settings |
| Voice sounds timid/quiet | Low sensitivity | Increase microphone amplification in sound settings |
| The microphone only works in headphones. | Contaminated main microphone | Clean the microphone hole (see tips above) |
If the problem persists after all the manipulations, try resetting the sound settings:
- Go to Settings → System and device → Resetting.
- Select Reset Sound Settings (does not affect personal data).
- After restarting, check the microphone again.
Hardware malfunctions: when to carry in the service
If the software methods don't work, you may have physical problems, and here are the signs that it's time to contact the service center:
- 🔧 The microphone does not work at all (neither in calls nor in records).
- 💥 On the body, cracks or dents are visible near the microphone hole.
- 🌊 After getting moisture (even if the phone is turned on).
- 🔊 In the dynamics, wheezing or distortions are heard when recording.
The cost of microphone repair on Xiaomi Redmi 9 in 2026:
- Replacement of the main microphone: 800-1500 ₽.
- Replacement of a plume with a microphone: 1500–2500 ₽.
- Cleaning from oxidation after moisture: 500–1000 ₽.
⚠️ Warning: If the phone was in water, do not dry it with a hair dryer or on a battery - this will accelerate the corrosion of contacts.