Many Xiaomi, Redmi and POCO smartphone owners face a nasty problem: they get background hissing, crackling or static noise, a phenomenon that can occur when wired through a 3.5mm connector, or when using Bluetooth headsets. Unnecessary sounds not only reduce the enjoyment of listening to music, but also interfere with telephone conversations, making the interlocutor difficult to hear. Often users think that the problem lies in faulty dynamics, but in 80% of cases the reason lies in software conflicts or incorrect settings of the MIUI interface.
Owners of Xiaomi devices often note that hissing can appear suddenly after updating the Android operating system or the MIUI shell. The system could automatically change the audio amplification settings or switch the audio codec to a less stable one. It is important to understand that digital signal processing in modern smartphones is very complex, and a failure in one module can cause audible artifacts (audible distortions). In this article, we will discuss all possible causes and methods of their elimination, from simple software resets to deep customization of the engineering menu.
Before you start complex manipulations, you need to rule out the trivial physical factors. If the hissing is heard in only one headphone and is accompanied by a mechanical crack when you touch the cable, most likely the wire or connector is damaged. However, if the noise is uniform, constant and varies depending on the volume or application running, then we are talking about software or electrical interference. Next, we will look in detail the diagnostic algorithms for different types of connection.
Diagnostics of the source of interference: hardware or software
The first step in solving the problem is to determine the exact nature of the malfunction, you need to understand whether the playback device (earphones) or the signal source (smartphone) is to blame. To do this, connect your headphones to another phone or computer. If the hissing persists, the problem lies in the hardware of the headset: perhaps the contacts have oxidized or the speaker driver is damaged, in which case the software settings of Xiaomi will not help.
If the other device is clear and your Xiaomi has noise, it means that the problem is localized to the phone. Often the cause is the accumulation of temporary files in the system audio buffer or driver conflict. Try to restart the smartphone in safe mode. To do this, press the power button, and then (hold) the "Stop" option on the screen until the suggestion to switch to Safe Mode appears. If this mode the hiss is gone, then it is the fault of the third-party application that you installed recently.
Also worth checking is the 3.5mm connector (if your model has one). The pockets often get dust and pile, which, when they get inside the socket, can cause the contacts to short, perceived by the system as a signal from the microphone or interference. Carefully inspect the hole under bright light. Using compressed air or a soft brush can remove debris that causes electrical tips.
⚠️ Warning: Do not use metal objects (needles, paper clips) to clean the headphone jack! you can damage or close the internal contacts, which will cause the audio codec on the motherboard to burn.
Customization of sound and equalizer in MIUI
The MIUI and the new HyperOS have powerful sound tools built in, which sometimes cause noise. Aggressively amplifying low frequencies or enabling virtual surround sound can overload the digital-to-analog converter (DAC), which manifests itself as hissing or wheezing. First, go to the Settings menu → Sound and vibration → Sound effects.
In this section, try to disable all active enhancements. Pay attention to the "Mi Sound", "Earphone Virtualization" and "Record Improvement" items. Post-processing algorithms may not work properly with certain headphone models, adding extra frequencies to the signal. Reset the equalizer settings to the "Default" or "Normal" values. Often users forget that they previously set manual sliders to the maximum, which causes distortion.
If you use wired headphones, check the settings in the special menu. Go to Settings → Sound and vibration → Headphone quality (the path may vary depending on the version of MIUI). Here the system suggests choosing the type of headphones. If you choose "Regular headphones", and you have a professional headset with high resistance, the sound may not be enough, and you twist the volume, increasing the background noise. Try switching the mode to "Hear with amplifier" or vice versa.
The Bluetooth absolute volume feature deserves special attention. Sometimes, when you de-synchronize your phone and headset volume levels, you get static. Sometimes you need to turn it on or off in the developer menu, which we'll talk about in the next section. Remember, any changes to the equaliser require you to restart the music app to take effect.
Working with Bluetooth connection and codecs
For wireless headphones, the problem of hissing is often related to the quality of the connection or the selected data codec. Xiaomi smartphones support various codecs: SBC, AAC, aptX, LDAC. High-quality codecs like LDAC require a stable signal; if the connection is unstable, the system can try to compensate for packet losses, which causes a digital crack. Switching to a simpler codec, such as AAC or SBC, often eliminates noise.
To manage codecs, you need to activate the developer menu. Go to Settings. → About the phone and quickly press 7 times on the item "Version" MIUI" (or "Version." OS"), until you have "You're a developer" on the screen, then go back to the main settings menu, select "More" →"For developers. Find the "Audio" or "Bluetooth audio codec" section".
In the list of available codecs, try to force you to choose SBC. This is the basic codec that provides the most stable, albeit less high-quality connection. If the hissing is gone, then the problem was the instability of high-resolution data transmission. Also in this menu there is the option "Disable absolute volume." Experiment with its state: sometimes separate control of the volume of the phone and headphones removes the background hum.
- 🎧 Reset pairing: Remove the device from the Bluetooth list, turn off the phone, turn on again and perform pairing again.
- 📡 Interference: Remove the phone from Wi-Fi routers and microwave ovens, they work at 2.4 GHz and can jam Bluetooth.
- 🔄 Firmware Update: Check in the headphone manufacturer’s app (e.g. Mi Earbuds, Galaxy Wearable) for Firmware updates.
Use of engineering menu and resetting of audio system
Xiaomi smartphones have a hidden engineering menu that allows you to test hardware components, including the audio system, and you can enter it by dialing ##6484## (CIT) or #4636##. From the CIT menu, select "Speaker" or "Headset." Here you can run test sounds. If there is no hissing in test mode, and there is a software problem, if the noise is heard even in the test, there is a hardware defect.
One effective way to eliminate the software glitches of an audio driver is to reset Bluetooth and network settings. Go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. Press Reset. This action will not delete your personal files, but will forget all stored Wi-Fi networks and Bluetooth devices. After rebooting, the system re-initializes the audio modules, which often removes accumulated errors.
| Method of decision | Efficiency | Difficulty | Risk of data loss |
|---|---|---|---|
| Phone reboot | Low. | Minimum | No. |
| Resetting sound effects | Medium | Low. | No. |
| Change of Bluetooth codec | Tall. | Medium | No. |
| Resetting network settings | Tall. | Medium | Wi-Fi passwords only. |
| Full reset (Factory Reset) | Maximum | Tall. | Total loss. |
If simple methods don't work, you can try a more radical step: clearing the cache of the system applications that control sound. Go to Settings → Apps → All apps. Find "Bluetooth", "System decoder", "Media Storage". Go to each of them and click "Clear Cache" (not data if you're afraid of losing settings, although for Bluetooth, cleaning data is safe, except for pairing passwords).
The problem of adapters and DAC-module
Many modern Xiaomi models lack a standard 3.5mm connector, forcing users to use USB-C to 3.5mm adapters. The sound quality and noise availability directly depends on the quality of this adapter. Cheap Chinese counterparts often do not have a built-in DAC (digital-analog converter) or use extremely cheap chips that catch tips from the phone’s motherboard, creating a constant hiss.
If you use an adapter, try replacing it with the original Xiaomi accessory or a certified analog (for example, from Apple, Samsung or specialized audio brands like Fiio or Moondrop). A good DAC has its own shielding and is properly matched with the USB-C port. Also, hissing can occur if moisture or dirt enters the USB-C port, creating a micro-circuiting of the power and signal contacts.
Another reason could be a lack of nutrition. USB-With headphones that are actively noise-canceling while charging the phone, a cheap power supply can give you a strong pulse of current that the audio chip perceives as noise. Try turning off the charger. If the hissing is gone, the problem is the tips from charging. use a high-quality power supply and cable, or listen to music from the battery.
When repairs are needed: hardware malfunctions
If all the software methods have been tried, the adapters have been replaced, and the hissing remains, most likely it is a physical failure. In Xiaomi smartphones, the audio codec is often soldered on the motherboard. When you fall or get moisture, the contact may go away or the track oxidize, and the 3.5 mm connector itself (if any), especially if you often use headphones in motion, could fail.
Symptoms indicating the need to go to the service center:
- 🔊 Hiss is audible even without connected headphones (from speakers).
- 💧 The phone has recently been exposed to moisture or high humidity.
- 📉 The volume of the sound dropped sharply, and a strong background appeared.
- ⚡ The phone warms strongly at the bottom (where the audio chip is located) during playback.
In such cases, self-repair is not recommended, as soldering and replacement of components at the micro level are required. Replacing the 3.5 mm connector is a procedure that is inexpensive and quick. If there is a problem in the audio codec on the board, more complex repairs may be required (rebolling or replacing the chip).
⚠️ Warning: If the phone is warranty, don't open it yourself! Any trace of an autopsy will result in a loss of warranty service.