How to check the speaker on the phone Xiaomi Redmi 9: full instructions with test codes

The speaker in Xiaomi Redmi 9 is one of the most vulnerable components after a year of active use. Dust, moisture, falls, or even a banal clogging of the headphone jack can lead to distortion, wheezing, or complete disappearance of the sound. But before you carry the phone to the service center, you should diagnose the problem yourself. In 80% of cases, you can detect a malfunction without disassembling the device - you just need to know the right combinations and tests.

This article will help you check the performance of the speaker on the Redmi 9 (including the Redmi modifications). 9A, 9C, 9T) We'll look at embedded tools, secret codes, and third-party applications, and we'll look at software failures (e.g., after an update). MIUI), And hardware problems, from oxidized contacts to damaged speaker membranes, will be particularly focused on diagnosing multimedia (bottom) and conversational (top) speakers separately, as their verification has key differences.

1. Quickly check sound through standard functions

Start with a basic diagnostics that doesn't require any additional software, and this method will help you determine if the lack of sound is due to a software failure or a physical malfunction.

Turn on any audio file (music, video or voice recording) on your phone and do the following:

• 🔊 Check the volume level: press the volume button. Sometimes the problem lies in accidentally activated "No sound" or reducing the volume to zero through the side keys.
• 🎧 Connect the headphones: if there is sound in them, and through the speaker is not, the problem is precisely in the hardware (the speaker or the train.
• 📞 Call another phone, and when you call, the sound must go through the speaker (top), and if you can't hear it, and the person you're talking to hear it, the top speaker is faulty.
• 🔄 Reboot the device: A banal rebuke often resolves temporary failures of the sound driver, especially after an update MIUI.

If sound is missing from all scenarios, move on to a deeper diagnosis, and if it only appears in certain situations (e.g., headphones or after a reboot), the problem is more software-based.

2. Secret engineering codes for testing speakers

Xiaomi Redmi 9 supports hidden service menus that allow you to test hardware components, including speakers. MIUI (11 to 14) and do not require root rights.

Enter the following combinations in the Phone app (as if you were dialing):

#4636### → Testing → Audio
##36446337## → EMT (Engineering Mode Test)
##0*#* → LCD- Test (includes sound check)

Once you enter any of the codes, you will be taken to the engineering menu, select Audio or LoudSpeaker and follow the instructions:

• 🔈 Normal Mode: Tests the main (bottom) speaker, must play clean sound without wheezing.
• 📞 Headset Mode: Checks the speaker's voice, the sound will be quieter, but should be clear.
• 🎵 Loopback Test: Includes feedback loops, where the microphone records sound from the speaker, useful for verifying the integrity of the audio track.

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If nothing happens after you enter the code, check if your carrier blocks them. Try using the codes through the application "Testing" (Mi Test), which can be downloaded from APKPure.

Pay attention to the following signs of malfunction:

3. Diagnostics through apps from Google Play

If the engineering codes didn't work or you want more detailed analysis, use specialized tools that allow you to test speakers at different frequencies, check the balance of stereo sounding and detect hidden defects.

Top.-3 applications for checking speakers on Redmi 9:

• 📱 Phone Doctor Plus: comprehensive diagnostics of all components, including the test speakers at maximum volume.
• 🔊 Speaker Test: Plays sounds of different frequencies (from 20 Hz to 20 kHz), helps to identify distortions in specific ranges.
• 🎛️ TestM: a professional tool for testing microphones and speakers with the ability to record and compare reference sounds.

How to use:

1. Install one of the applications and open it.
2. Select the Speaker Test or Audio Test section.
3. Follow the instructions on the screen – usually confirm that you hear the sound.
4. Pay attention to the visual indication: if the application shows that the sound is being played, but you can’t hear it, the problem is hardware.

Close all background applications

Turn off the Bluetooth headphones.

Set the volume to maximum.

Check if the "Do Not Disturb" mode is activated"-->

If an application produces an error such as Audio device not found, this may indicate:

• No sound drivers (solved by flashing).
• Damage to the audio chip on the motherboard.
• Blocking sound at the level MIUI (Check the permissions for the application).

4. Checking contacts and plumes without disassembly

Often the problem is not the dynamics itself, but the plume that connects it to the motherboard. On the Redmi 9, this plume is located under the back cover and can oxidize or retreat when it falls.

Method 1: Light tapping on the body

Carefully tap your finger on the bottom of the phone (where the speaker is) as you play the sound. If the sound appears or changes, it's a sign of poor contact. Temporary solution: bend the body in the speaker area (no bigotry!) so that the plume is better pressed.

Method 2: Vibration testing

Turn on the music at maximum volume and put your finger on the speaker. You have to feel the vibration. If there's no vibration, but the headphones have sound, the speaker is malfunctioning. If there's vibration but there's no sound, there's a problem in the membrane (e.g., dust clogging).

Method 3: Testing with a hair dryer

If the phone was in a wet environment, the contacts could oxidize. Heat the bottom of the phone with a hair dryer (temperature no higher than that). 50°C!) during 1-2 If you've had a sound after that, but then it's gone again, you need to clean the contacts with alcohol.

⚠️ Warning: Don't use a microwave or oven to heat up! This can melt plastic elements inside your phone. Also avoid direct hot air on the screen - it's sensitive to overheating.

5. Hardware diagnostics: when you can not do without disassembly

If all the software methods are not working, you'll have to look inside the phone. On Redmi 9, the speaker is located under the back cover and attached to the case with double-sided tape.

• 🔧 Plastic blade or mediator.
• 🔩 Cross screwdriver (usually) T4 or T5).
• 🧴 Isopropyl alcohol (90%+) clean-up.
• 🔍 Lupa (optional, to inspect small details).

Step-by-step:

1. Turn off the phone and remove it. SIM-map.
2. Heat the back cover with a hairdryer (to soften the glue) and gently tuck it with a spatula, starting at the corner next to the headphone jack.
3. Unscrew 8 screws that fix the metal plate (do not lose them - they are of different lengths!).
4. Disconnect the battery plume (black connector with a red marker) to avoid short circuit.
5. Find the speaker - it is located at the bottom next to USB-Check the integrity of his plume and the contacts on the motherboard.
6. If the contacts are oxidized, clean them with alcohol and a cotton swab. If the plume is damaged, it needs to be replaced.

Pay attention to the following details:

• Color of contacts: They should be shiny, without green or white coating (a sign of oxidation).
• Dynamic membrane integrity: If it is torn or deformed, the speaker must be replaced.
• The presence of foreign objects: sometimes dust or fibers from napkins accumulate under the membrane.

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If you do not have experience in disassembling phones, it is better to entrust the diagnosis to professionals. The cost of replacing the speaker in the service is from 500 to 1500 rubles, while self-repair can lead to damage to the battery plume or motherboard (repair price is from 3000 rubles).

6. Frequent causes of speaker failure on Redmi 9

Analysis of service center calls shows that 90 percent of the speaker problems on the Redmi 9 are due to five main causes, and knowing them will help you diagnose the malfunction more accurately and choose the best way to repair it.

Redmi is especially vulnerable. 9 Even a brief exposure to rain can cause corrosion of the speaker's contacts through the 1-2 If the phone is in the water, immediately:

1. Turn it off and remove the battery (if possible).
2. Wet with a napkin the visible moisture.
3. Place in a silica gel bag (out of a shoe box) for 48 hours.
4. Do not turn it on until you are sure of complete drying!

⚠️ Warning: Do not use a dryer to dry a wet phone immediately after moisture hits! this can drive water deeper into the case and cause a short circuit. 10-15 minutes, then proceed to drying.

7. Software failures: resetting settings and flashing

If the hardware diagnostics didn't reveal any problems, but the sound is still missing, the software is to blame. The following crashes are most common on Redmi 9:

• 🔄 Resetting sound settings: after the update MIUI The audio chip configuration may be lost. Corrected by resetting to factory settings (Settings) → The phone. → Resetting settings).
• 📱 Application conflict: Some programs (e.g. Equalizer or Dolby Atmos) may block system sound.
• 🖥️ Firmware damage: If the sound is gone after a failed update, flashing through Fastboot or Recovery will help.

For flashing through Recovery:

1. Download the official firmware for Redmi 9 From Xiaomi (select the Lancelot model for Redmi) 9, dandelion for 9A/9C).
2. Rename the file to update.zip and place it in the root of the phone’s memory.
3. Press Power + Volume Up to Enter Recovery.
4. Select Install update.zip and wait until it is completed.

If you don't flash the sound after you flash it, it's just hardware, and then you can just change the speaker or the plume.

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Before resetting or flashing, back up your data! Use Settings → Additionally. → Backup and reset or Mi Cloud app to save contacts and photos.

FAQ: Answers to Frequent Questions