Problems with recording on budget smartphones often come as an unpleasant surprise, especially when the interlocutor stops hearing you or complains about background noise. the Redmi 7 model, released in 2019, is still actively used, and the issues of setting up its audio modules remain relevant. The correct configuration of the microphone sensitivity can dramatically improve the quality of calls through instant messengers and regular voice calls.
In this article, we will discuss not only the basic settings available on the menu, but also the hidden engineering capabilities of the MIUI system. You will learn how to diagnose equipment to exclude software failure or physical failure. Competent settings allow you to compensate for age wear of the speaker membrane and improve speech intelligibility.
Before you start to do complex manipulations, you need to make sure that the basic parameters of the system are configured correctly. Often users accidentally change the privacy settings or block the access of applications to the audio input, which leads to silence in the handset. Let's start by checking the permissions and standard recording options.
Xiaomi’s Android shell system has strict hardware access rules. If an app is not allowed to use a microphone, no sensitivity settings will help it. Check Settings → Apps → App settings → Permissions Manager → Microphone. Make sure the switches opposite the right programs (WhatsApp, Telegram, Recorder, Phone) are active.
You also need to look at the noise reduction feature, which is built into the phone's software. It can work incorrectly, cutting down the quiet sounds along with the background noise. To turn off or adjust this feature, go to the call menu, click three dots in the corner, and select Settings. Look for the noise reduction item and experiment with its state.
⚠️ Warning: Turning off noise cancellation may cause the person to hear wind or street sounds if you are outdoors. Use this option only in quiet rooms.
After checking the permissions, it is recommended to reset the audio settings to factory values if manual equalizer changes were previously made.This will return the frequency characteristics to the optimal parameters calculated by the engineers for Redmi 7. Sometimes the driver software conflict is solved by simply restarting the audio services through a device restart.
To further adjust the sensitivity of the microphone on Xiaomi smartphones, there is a hidden engineering menu, accessed through a special code that opens the CIT (Customer Information Test) diagnostic interface, which allows you to test each module of the phone separately, including the main and secondary microphones.
To get into the testing menu, open the Phone app and dial the combination ##6484##. If the code didn't work, try ##4636##, although the first option is more informative for checking the hardware. In the list that opens, find Microphone or Main Mic. When you click on it, you run the recording test.
So during the test, the system will ask you to talk into the microphone, and then play back the recording, and it will tell you if the audio input is working at all, and how clean it is, and if the recording is missing or crackling, it's probably hardware, but if there's sound, it's too quiet, you can try calibrating.
What to do if the engineering menu is not opened?
Some versions of firmware have calibration available through the engineering menu. Find Calibration or Audio Calibration. It takes a few seconds for the phone to not make sounds. Calibration resets the software to factory values, which often solves the problem of quiet sound.
Do not use the engineering menu often unnecessarily, as randomly changing parameters in sections marked as RF Test or Connectivity can disrupt the radio module.
Sound quality is directly dependent on which app you use to transmit voice. Xiaomi's standard Dictophone app has its own settings that may conflict with system settings. Let's figure out how to optimize voice recording.
Open the Dictophone app and click on the menu icon (three bars or dots). Select Record Settings. Here you are interested in Record Quality. By default, it can stand in Standard or Economy. Change it to High. This will increase the bitrate of the record, making the sound more detailed, although it will take up more space in memory.
Also, the microphone settings often include the "Mic Type" option, if you use a headset, select the appropriate mode. To record speech in silence, the "Voice" mode is preferable to the "General" mode, since it uses specific frequency filters characteristic of human speech, cutting off excess low and high frequencies.
When using third-party apps like Zoom or Skype, the settings of the app itself can override system settings. Go to the settings of a particular messenger, look for the “Sound” or “Audio” section, and make sure that it does not include aggressive noise cancellation or, conversely, amplification that causes distortion.
The physical condition of the device is as important as the software settings. The Redmi 7 is not new, and over the years, the microphone holes may have been clogged with dust, skin fat, or pile from your pocket, the most common cause of quiet sound.
The main microphone is usually located on the lower end of the case, next to the Micro-USB charging connector. An additional noise reduction microphone is on the upper end. Carefully inspect these holes in good light. If you see gray dust lumps, they must be carefully removed.
Use a soft toothbrush or dry antistatic brush to clean, and it is strictly forbidden to use sharp metal objects (needles, pins) because they can easily damage the protective net or the microphone membrane itself located inside, and it is also not recommended to blow with your mouth, as moisture from breathing can oxidize the contacts.
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Before cleaning the microphone, walk slightly through the holes with a dry toothbrush in circular motions to fluff the compressed dust, and then use the pear to blow out the garbage.
If you use a protective case, remove it and check if it covers the microphone holes. Some cheap cases have inaccurate cutouts that partially or completely block the sound. This is a common problem that users often overlook.
☑️ Microphone diagnostics
The table below gives the main symptoms of malfunctions and their likely causes, which will help you diagnose an audio login problem faster on your Redmi 7.
| Symptoms. | Probable cause | Method of decision |
|---|---|---|
| The interviewer doesn't hear at all. | Pollution, software failure, plume breakdown | Cleaning, rebooting, replacing the module |
| Quiet sound, you need to scream. | Grid's clogged, calibration's gone. | Brushing, resetting the sound settings |
| Squeak, crack, static. | Moisture intrusion, contact oxidation | Drying, cleaning with alcohol, replacement |
| Sound, I mean, no. | Bad plume contact, software bug | Reconnecting the plume, reflashing |
By analyzing symptoms, you can save time and money. If the problem manifests itself in only one particular application, for example, only in Viber, then it is definitely not the hardware. If the recorder also writes silence or crack, then the problem is system or hardware.
Note the headphone jack. In some cases, oxidation of the contacts in the 3.5 mm jack can give false signals to the system that thinks that the headset is connected and switches the audio input to it. Try several times to insert and remove the headphone plug to mechanically clear the contacts.
If software and cleaning methods didn't work, you might need to change the microphone. On the Redmi 7, the main microphone is often soldered on the bottom board, which also houses the charging connector, which makes repairs easier, since you don't have to disassemble the entire phone completely, but you need soldering skills.
To replace, you'll need a set of screwdrivers, a suction cup to open the case and possibly soldering equipment.The process begins with turning off the phone and removing it. SIM-The back cover (dryer or heating pad) is then heated to soften the glue, after which it is carefully removed.
⚠️ Warning: When opening the case, be extremely careful.The fingerprint scanner plume in Redmi 7 is glued to the lid and very short - it is easy to tear if taken carelessly.
Once the lid is removed, the plastic frame is unscrewed, covering the battery and the plumes, the battery plume is disconnected, then the bottom board is unscrewed, and if the microphone is embedded in the charging board (which is most common), the replacement is reduced to replacing the entire small board, and if the microphone is separate, it is soldered out and a new one is put in.
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Replacing the lower board with a microphone with a Redmi 7 is the most reliable way to repair, since it eliminates soldering errors of the small component and solves the problem with the charging connector at the same time.
Make sure to make a test call after assembly. If the sound appears but becomes distorted, check if the board is tightly pressed against the case and the plume is squeezed. Incorrect assembly can lead to new problems with sound.
There are a number of myths and questions that users often have when tuning a sound, and below we will answer the most popular ones to give you a complete picture.