A constant hum, crackling or echo in the speaker of an Android smartphone during a call often indicates a malfunction of the microphone, damage to the cable or a conflict of installed applications, which requires immediate diagnosis to restore the quality of communication.
Before taking the gadget to a service center or When buying a new one, you need to carry out in-depth diagnostics. Often the reason lies not in the smartphone itself, but in external factors: a poor signal from a cell tower, low-quality accessories, or malfunctions of the telecom operator. In this article we will analyze in detail why phone phone, what settings Android can affect the sound quality and how to independently eliminate most problems associated with voice transmission.
The influence of the quality of the cellular network and signal
The most common cause of interference is an unstable cellular network signal. When your smartphone is in an area of poor coverage or at the border of two towers, it is forced to constantly switch between frequencies or increase the transmitter power. This results in digital artifacts that we perceive as crackling or robotic voices. This happens especially often in basements, elevators or country houses.
Voice compression algorithms in networks 2G and 3G work differently than in modern standards VoLTE and 5G. If your phone is forced to switch to an outdated communication standard due to congestion on the main network, the sound quality will inevitably drop. In such cases, the interference is temporary and disappears when you move into an area of reliable reception. However, if the problem is observed constantly in the same location, it is worth checking the network settings.
⚠️ Attention: If interference occurs only when making calls via a mobile network, but disappears when using instant messengers (WhatsApp, Telegram) via Wi-Fi, the problem is 90% related to the operator's coverage, and not to your device.
Sometimes The situation is aggravated by the fact that the smartphone tries to hold onto a weak signal instead of switching to another tower. In this case, temporarily changing the network mode helps. Try going to Settings → Connections → Mobile networks and force selecting mode Only 3G or Only LTE. This will allow you to understand which communication standard provides the best sound quality in your area.
Problems with accessories and headsets
If you use wired headphones, a Bluetooth headset, or a hands-free car kit, the noise source may be located in them. Cheap accessories often do not have proper shielding, which is why the cable acts like an antenna, catching interference from other electronic devices or the electrical network itself. This creates a characteristic low-frequency hum or high-frequency whistle.
Particular attention should be paid to the condition of the connector 3.5 mm or port USB-C. Moisture, oxidation of contacts or ordinary dust can disrupt the electrical contact, leading to an intermittent signal and crackling noise. In the case of Bluetooth devices, the problem may lie in signal interference. If powerful Wi-Fi routers, microwave ovens or other transmitters are operating nearby, they can “clog” the headset’s communication channel.
To diagnose, you need to perform a simple action: disconnect all external devices and make a test call using only the built-in speaker and microphone of the smartphone. If the noise disappears, then the problem is localized in the connected equipment. It is also worth checking whether the function Sound enhancement or Surround sound is enabled in the Bluetooth settings, since on some models Android it does not work correctly with certain codecs.
- 🎧 Check the integrity of the headphone cable: kinks and chafing often cause short circuits in the channels.
- 🔌 Clean the charging connector and audio output with a soft dry brush from dust and lint.
- 📶 Try disconnecting other Bluetooth devices to eliminate frequency conflicts.
Android software crashes and sound settings
The operating system Android provides many tools for processing sound, but sometimes they fail. Built-in noise reduction algorithms, which should cut off extraneous sounds, may not work correctly and, conversely, distort the interlocutor’s voice or add artifacts. This often happens after an unsuccessful firmware update or installation of third-party applications that have access to the microphone.
It is worth checking your accessibility settings. Some features designed for the hearing impaired may amplify certain frequencies, creating a metallic or echoing effect. Go to Settings → Accessibility → Hearing improvement and make sure all switches are turned off if you are not using them. The culprit may also be the Do Not Disturb mode or third-party equalizers that change the frequency response of the microphone.
How to reset sound settings without losing data?
Go to Settings → Applications, find the “Phone” or “Sound” system application, click “Storage” and select “Clear cache”. This will not delete your contacts, but it will reset your call handling settings.
Another hidden cause is background processes. If during a conversation an application tries to record audio in parallel with a phone call (for example, a voice recorder or voice assistant), a resource conflict may occur, which appears as a squeak. Close all running applications before making a call to eliminate this factor.
⚠️ Attention: After updating the firmware, audio codec settings may be reset. If the problem appeared immediately after the update, try resetting the network settings (
Settings → General settings → Reset → Reset network settings).
Physical damage to the microphone and speakers
When software methods do not help, you have to suspect the hardware. Modern smartphones have several microphones: the main (below), an additional one for noise reduction (above) and sometimes a third one for video recording. If the main microphone becomes dirty or fails, the system can automatically switch to an additional one, which is not designed to transmit voice with such quality, which causes dull, distant sound with backgrounds.
Moisture ingress is the main enemy of the speaker system. Even if the phone has standard protection. data-i="84">or IP67 or IP68over time, the sealing gaskets wear out. Microscopic drops of water that get inside the case can cause corrosion of the contacts of the speaker or microphone membrane. This manifests itself not only in the loss of sound, but also in the appearance of constant static noise.
You can diagnose a breakdown using the engineering menu or special testing applications. equipment. Try recording your voice with your hand over the bottom hole. If the recording is clear, but there is noise during the conversation, the problem may be with the top noise-canceling microphone, which is sending incorrect data to the signal processor.
| Symptom | Probable cause | Check method |
|---|---|---|
| Constant quiet hum | Short circuit in the microphone circuit | Recording on a voice recorder in silence |
| Crackling sound when moving | Outgoing cable or contact | Gently pressing the back cover |
| Echo of your voice | Noise reduction failure | Call with the speaker on |
| Robotic voice | DAC/ADC or network problem | Comparison of calls via SIM and Wi-Fi |
If the voice recorder records clear sound, but there is noise - the problem is most likely in the radio module or operator settings, and not in the microphone itself.
Conflicts with the telecom operator and VoLTE
Technology VoLTE (Voice over LTE) allows you to transmit voice in high quality via the 4G network, but its implementation is on different devices and with different operators may vary. If your smartphone and SIM card support this function, but the setup is not performed correctly, desynchronization of data packets may occur and, as a result, audio interruptions or metallic sounds.
Sometimes the telecom operator carries out technical work on towers or changes frequency bands, which temporarily affects the quality of communication in your region. In such cases, the phone may try to use an unsupported frequency range (Band), resulting in an unstable connection. You can find out the current settings for your region in your operator’s personal account or on the official website, as the parameters may change.
Try to disable the VoLTE function in the mobile network settings. The path usually looks like this: Settings → SIM cards and mobile networks → Using VoLTE. After disconnecting, the phone will switch to classic voice (CSFB), which may reduce the sound quality to HD levels, but will eliminate digital interference if it is caused by protocol incompatibility.
☑️ Diagnosis of a problem with the operator
Electromagnetic interference and external factors
A smartphone is a complex radio-electronic device that is sensitive to external fields. If you are near powerful sources of radiation (transformer boxes, power lines, medical equipment, industrial engines), stray currents may be induced in the audio path of the phone. This causes a characteristic low-frequency hum or pulsed noise, synchronized with the operation of external equipment.
The charger is also worth considering. Using cheap power supplies without high-quality filtering can create strong interference on the smartphone's audio circuit, especially if you are talking while charging. Try disconnecting your phone from the network and making a call on battery power. If the noise disappears, replace the charger with an original or certified one.
In rare cases, static electricity becomes the cause. Dry indoor air and synthetic clothing can accumulate a charge that, when discharged through the phone's body, creates a clicking sound in the speaker. Humidifying the air or using antistatic sprays can help in such situations.
⚠️ Warning: Never try to shield your phone with foil or metal covers during a call. This can completely block the signal, forcing the phone to operate at maximum radiation power, which will only increase interference and drain the battery.
Comprehensive solution and factory reset
If none of the above methods fixed the problem, the last software step remains - a complete factory reset. This action will remove all installed apps and user data, returning the phone to its factory state. Often the cause of background noise is mining viruses or malware that use the microphone in the background, creating conflicts.
Before performing a reset, be sure to back up your important data to cloud storage Google Drive or to your computer. After the reset, do not restore all applications in a batch at once. Test the phone in a “clean” state: insert a SIM card and make several calls. If the sound is clear, install applications one by one to identify the culprit.
In a situation where, even after resetting the firmware and checking in different locations phone phone, it is highly likely that there is a physical malfunction of the audio codec on the motherboard or detachment of contacts. In this case, independent repairs without a soldering station and a microscope are impossible, and you will need to contact a service center.
Before visiting the service, record the sound with a voice recorder and during a call through the speakerphone. This will help the technician quickly understand the nature of the noise (hardware or network).
Why does the phone make noise only when charging is connected?
This is a classic sign of a low-quality power supply or cable. Cheap chargers do not have sufficient galvanic isolation and filtering, which is why alternating current from the outlet is induced into the audio circuits of the smartphone. Try using the original charger or charging the phone from the USB port of your computer.
How to check if the microphone is working on Android?
Use the standard “Voice Recorder” application. Record your voice in a quiet room, then play the recording back. If there is a crackling or hum in the recording that is also heard in real life, then the microphone is physically damaged or dirty. If the recording is clear, but there is noise during a call, there is a problem in the network or the radio module.
Can a case cause interference during a conversation?
Yes, if the case is made of metal or contains metal inserts. They can shield the antenna signal, causing the phone to amplify the transmitter power, which indirectly affects the level of interference. In addition, a thick case may block the holes of the secondary noise-canceling microphones.
What should I do if the other person hears an echo of my voice?
Echoes most often occur when sound from your phone's speaker enters your microphone and is returned to the other person. Try turning down the speaker volume. If this does not help, the noise-canceling microphone (top) may be faulty, which should cut out environmental sounds but instead amplifies them.
Does full memory affect sound quality?
Extremely rare, but possible. If the system memory partition is full, the processor may not be able to process the audio stream in real time, which leads to audio stuttering and digital artifacts. Freeing up 1-2 GB of free space can solve the problem of software delays.