How to improve the sound quality in headphones on Xiaomi Redmi 9: the complete guide

The sound in the headphones on Xiaomi Redmi 9 often disappoints users — quiet bass, distorted high frequencies or insufficient volume spoils the impression of music and video. The problem is not always in the headphones themselves: often to blame the wrong settings, MIUI limitations or hardware features of the smartphone. Fortunately, you can fix the situation without buying new headsets — quite competently configure the software and take advantage of hidden functions.

In this article, we’ll look at 10 proven ways to improve sound on Redmi 9, from basic equalizer settings to advanced tweaks through the engineering menu. All methods tested on MIUI 12-14 and do not require root rights, unless otherwise noted.

1. Set up the built-in MIUI equalizer

The first thing you should try is the regular equalizer in the firmware, which is hidden in the sound settings, but it allows you to significantly improve the bass and the purity of the sound.

1. Open the Settings app.
2. Go to Sound and Vibration → Sound Quality.
3. Activate the Equalizer slider.

Redmi 9 has 5 preset profiles (Rock, Pop, Classics, etc.), but it is better to choose User and manually adjust the frequencies:

• 🎵 Bass (60-250 Hz): raise to +3-5 dB for depth.
• 🎶 Average (500–2000 Hz: leave at zero or slightly mute (-1 dB) to remove "dirty".
• 🔊 High (4000–16000 Hz): add +2–3 dB for brightness.

⚠️ Attention: Excessive bass reinforcement (>+6 dB) on cheap headphones can cause clipping, which is a distortion of the sound at high volume. On Redmi 9, it manifests as wheezing at maximum level.

2. Enable the "Mi Sound Enhancer" function

Mi Sound Enhancer is Xiaomi’s proprietary audio enhancement technology that automatically optimizes the frequency response for connected headphones. In Redmi 9, it works only with wired headsets and is turned off by default.

To activate:

1. Connect the headphones to your smartphone.
2. Go to Settings → Sound and vibration → Sound quality.
3. Find the Mi Sound Improvement item and turn it on.

The function analyzes the impedance of the headphones (resistance) and adjusts the output signal. The effect is noticeable on models with impedance 16-32 Ohms (most budget headphones).

Are the earbuds properly connected (to the point)?

Is the Mi Sound Improvement slider on?

Have you tried to turn off/enable the function again?-->

3. Use of third-party equalizers

The built-in MIUI equalizer is limited to 5 bands and does not save settings for different headphones.

• 🎧 Wavelet (with support) LDAC and aptX for Bluetooth headphones).
• 🎛️ Poweramp Equalizer (10-band equalizer) + genre-prestige).
• 🔊 ViPER4Android (Advanced sound processing requires Magisk).

For installation of Wavelet (recommended for beginners):

1. Download the app from Google Play.
2. Include audio effects in the application settings.
3. Select Auto EQ preset – it will automatically select the settings for your headphones.

⚠️ Attention: Apps like ViPER4Android require root access or Magisk module. On Redmi 9, this can lead to loss of warranty and problems with the software. OTA-update.

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Before installing a third-party equalizer, turn off the built-in MIUI to avoid sound processing conflicts.

4. Sound optimization through engineering menu

The engineering menu (#4636##) allows you to fine-tune the Redmi 9 audio chip. Careful: incorrect settings can worsen the sound or cause crashes.

Instructions:

1. Open the Phone app and type ##4636##.
2. Select Hardware Testing → Audio.
3. In the Headset section, change:

Headset Volume: 150 (maximum)


Headset Mic Volume: 100 (default)




Speaker Volume: 120 (for speaker)

After applying the settings, restart the smartphone.

• 🔊 Headphone volume will increase by 20-30%.
• 🚫 Risk of distortion at maximum volume (solved by lowering the level in the player).

5. Checking and replacing the audio jack

If the sound disappears in one earphone or there are interference when moving the plug - a problem in the audio jack 3.5 mm. on Redmi 9 it is a frequent malfunction due to budget assembly.

Diagnosis:

• 🔍 Check the connector for oxidation or bent contacts.
• 🎧 Check the headphones on another device.
• 🔊 Move the plug in the connector - if the sound appears, then disappears, contact is broken.

Decisions:

1. Clean the connector: Use a toothpick and alcohol to remove dust.
2. Replacement of the connector: in the service center (cost) ~500–800 ₽).
3. Bluetooth adapter: If the connector is permanently broken, buy a Bluetooth transmitter (for example, Baseus WM01).

⚠️ Warning: Do not use metal objects to clean the connector - this can close contacts and disable the audio chip.

6. Customization of sound for specific applications

Some apps (like YouTube or Spotify) have their own audio settings that override the system settings. On Redmi 9, this can lead to conflicts.

For YouTube:

• 🎵 Open the video. → press on ⚙️ → Quality. → Reproduction speed.
• 🔊 Set Volume Normalization to Off (it compresses dynamic range).

For Spotify:

1. Go to Settings. → Reproduction.
2. Activate High Flow Quality (320 kbps).
3. Turn off the automatic volume normalization.

For games (such as PUBG Mobile or Call of Duty):

• 🎮 In the game settings, find the Sound section and turn on 3D-audio (if any).
• 🔊 Set the volume of effects to maximum, and the volume of music to 30%.

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The sound settings in apps take precedence over the system settings, and always check them first if the sound is worse only in a particular software.

7 Hardware enhancements: amplifier or external sound card

If software methods didn’t work, consider hardware solutions. The budget audio chip in Redmi 9 isn’t physically capable of delivering high-quality sound on expensive headphones (impedance >50 Ohms).

Options:

To connect an external sound card to Redmi 9 need to OTG-adapter (Type-C) → USB-A). Make sure your firmware supports USB Audio Class 1.0/2.0 (checks in the settings → The phone. → The kernel version).

8. Update firmware and reset sound settings

Sometimes the sound problems are caused by firmware bugs. Xiaomi regularly releases updates for Redmi 9, correcting audio bugs.

1. Go to Settings → About the phone → System update.
2. Click Check for updates.
3. If a new version is available, download it and install it.

If the sound worsens after the update, reset the sound settings:

1. Go to Settings → Applications → Application Management.
2. Find Media (or Media Storage) and click Warehouse → Clear Data.
3. Reboot your smartphone.

⚠️ Attention: Resetting media settings will delete all custom equalizer presets and playback history in system players. Backups do not help - settings are stored in the system cache.

FAQ: Frequent questions about the sound on Redmi 9