Xiaomi Redmi 9C is a budget smartphone with decent specs, but many users face the problem of quiet sound in headphones. Even at maximum volume, music or video can sound too quiet, especially if the headphones are high resistance. In this article, we will discuss all possible ways to increase the volume, from standard settings to hidden functions of the engineering menu and third-party utilities.
It's important to understand that volume limits are often set by the manufacturer to protect your hearing, but if you're sure your headphones are up to a higher level of sound and the current volume is not enough, follow our recommendations. The Redmi 9C (codenamed angelica) has unique MIUI settings that are not available in pure Android, and we'll use them too.
Before you start changing the settings, check the baseline: connect the headphones to another device to prevent them from malfunctioning, and clean the 3.5 mm connector of dust. If the problem persists, proceed to settings.
1. Standard volume settings in MIUI
So, to start with, the simplest thing is to check and adjust the basic sound parameters in MIUI, and often users don't know where to look for the right regulators.
Open the Settings app, go to the Sound and Vibration section, and here you are interested in:
- 🔊 Multimedia volume is a slider for adjusting the sound level when playing music/video.
- 🎧 Amplify the sound in headphones - an option can be called MI Sound Enhancer (not available in all versions) MIUI). Activate it if you have it.
- 🔄 Separate settings for headphones – in some firmware, the volume for speakers and headphones is adjusted independently.
If your MIUI version doesn’t have MI Sound Enhancer, try upgrading to the latest stable version. Go to Settings → About Phone → System Update. Redmi 9C supports updates to MIUI 14 based on Android 12, where audio settings are extended.
2. Engineering menu: hidden sound settings
If the standard options don't work, it's time to look at the Engineering Mode, which is a hidden section of Android where you can manually adjust the sound card settings, including volume limits.
To open the engineering menu on Redmi 9C:
- Open the Phone app.
- Enter the combination: ##36446337##
- Choose Hardware Testing → Audio.
In the Audio section you are interested in:
- 🔧 Headset Mode is a headphone mode, and you can increase the Max Vol value for left and right channels.
- 📊 Normal Mode is the basic sound settings. Change the settings carefully so you don't distort the sound.
- 🔄 Speaker Mode – speaker settings (not to be confused with headphones!).
What are the values to change in the engineering menu?
⚠️ Warning: Changing the settings in the engineering menu can damage your headphones or smartphone speakers if you set the values too high.
| Parameter | Standard value | Recommended value | Maximum permissible |
|---|---|---|---|
| Headset Max Vol | 100 | 120–130 | 150 |
| Headset Min Vol | 0 | 5–10 | 20 |
| Headset Media Vol | 84 | 100–110 | 130 |
3. Sound amplification applications
If you don't want to dig into settings or take risks with the engineering menu, you can use third-party apps, which work like amplifiers, increasing the volume programmatically.
Top.-3 Proven applications for Redmi 9C:
- 🎵 Volume Booster GOODEV — It's a simple app with volume control up to 200%, supports separate profiles for headphones and speakers.
- 🔊 Equalizer FX — Not only does it amplify the sound, but it also allows you to tune the equalizer to improve the quality.
- 🎧 Precise Volume – gives precise volume control in 1% increments, which is useful for fine tuning.
Install any of these apps from Google Play, plug in your headphones and turn up the volume through the program interface. Note that some utilities require permission to change system settings - only give it to trusted applications.
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Before using sound amplifiers, check if your headphones are louder, and cheap models can start wheezing or fail.
4. Equalizer adjustment to improve sound
Sometimes the problem isn't volume, but the wrong equalizer settings. For example, if the bass or high frequencies are too suppressed, the sound seems quieter. The Redmi 9C has a built-in equalizer that you can customize to your preferences.
How to open the equaliser:
- Run any audio app (such as Music or YouTube).
- During playback, tap on the icon. ⚙️ Settings or Equalizer (depending on the player).
- Choose preset (Rock, Pop, Jazz) or create your profile.
Recommended settings for maximum volume:
- 📈 Increase the sliders by 100–200 Hz (bass) and 3–6 kHz (medium frequencies) – this will make the sound more saturated.
- 🔽 Reduce extreme low (60 Hz) and high (12-16 kHz) frequencies if they cause interference.
- 🔄 Turn on the option. 3D-sound or stereo expansion, if any.
⚠️ Warning: Excessive bass reinforcement can cause sound distortion at high volume, especially in cheap headphones.
5. Check of the 3.5 mm connector and headphones
If the sound stays quiet despite all the settings, the problem may be the physical connection. The 3.5mm connector on the Redmi 9C is not the most reliable — it often clogs up with dust or oxidizes.
What to do:
- 🧹 Clean connector - use a toothpick or compressed air to remove dust. Do not use metal objects!
- 🔌 Contact check -- sway the headphone plug slightly in the connector. If the sound is interrupted, the problem is poor contact.
- 🔄 Test other headphones - connect knowingly working headphones to exclude their malfunction.
- 🛠️ Salting of the connector - if the contact disappears with the slightest movement, you may need to solder the connector (it is better to contact the service).
If you use Bluetooth headphones, check:
- 📶 Signal Level – A weak signal can lower volume.
- 🔋 Headphone charge – discharged headphones often sound quieter.
- 🎵 Codecs - in Bluetooth settings (Settings) → Connected devices → Settings gear next to the headphones select the codec AAC Or aptX for better sound.
☑️ Diagnostics of Sound Problems
6. Resetting the sound settings to factory
If you've experimented with the settings and the sound gets worse, there may have been a configuration failure, and then resetting the sound settings will help.
How to reset the sound settings:
- Go to Settings → System and device → Resetting.
- Select Resetting Sound Settings (or Resetting All Settings if the first item is not available).
- Confirm the action. The phone will reboot.
After discharge:
- 🔄 Volume will return to standard values.
- 🎵 All user presets of the equalizer will be removed.
- 🔊 Bluetooth headphone settings will also reset.
⚠️ Warning: Full reset (Reset to factory) will remove all data from your phone, including photos and apps. Use it only as a last resort and pre-backup.
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If resetting the audio settings didn't help, the problem could be the firmware. Try updating MIUI to the latest version or reflashing the phone.
7. Alternative methods: from firmware to repair
If none of the above methods worked, consider the more radical options:
1. Phone flashing
Some custom firmware (such as LineageOS or Pixel Experience) offer advanced audio settings without restrictions. MIUI. However, this requires unlocking the bootloader and may take away the warranty.Detailed instructions on Redmi firmware 9C:
How do I flash Redmi 9C?
2. Replacement of the sound chip
If the sound is quiet even in the dynamics, the problem may be in the audio codec (the chip responsible for processing sound). The Redmi 9C uses a Qualcomm WCD9370 chip. Its replacement requires soldering and costs ~1,500-2,500 rubles at the service center.
3.Use of external DAC
For music lovers, the best option is to connect an external digital-to-analog converter (DAC) via USB-C. For example, Xiaomi USB-C to 3.5mm Headphone Jack Adapter or more advanced models from Fiio or AudioQuest.