The quality of wireless sound often disappoints owners of modern smartphones, especially when using expensive headphones. By default, Android selects the base codec SBC to ensure maximum compatibility, ignoring the capabilities of your hardware. This leads to compression of the audio stream, loss of detail and sound that is far from Hi-Res standards.
Many users do not even suspect that their smartphone and headset support advanced encoding algorithms, such as LDAC, aptX HD or LHDC. The problem lies not in the hardware, but in software limitations and priorities of connection stability over data transfer quality. Fortunately, there are ways to bypass these limitations and unlock the potential of your audio system.
In this article we will look in detail at how to force a codec switch, what tools you will need for this, and what you should be wary of when tampering with system settings. You'll learn how to control bitrate and sample rate settings, turning your smartphone into a full-fledged source of high-quality sound.
Why Android chooses low sound quality
The Android operating system is designed to work on thousands of different devices, so versatility is a priority. When pairing with a new device, the system performs a quick handshake to determine the common codecs supported. If strict rules are not set, the algorithm will choose the most stable option, which is almost always SBC or AAC.
This decision is dictated by the desire to avoid connection breaks and delays when playing video. However, for music lovers this approach is unacceptable. High-resolution codecs require a wider data transmission channel and a stable signal, which is not always guaranteed in noisy radio conditions.
In addition, smartphone manufacturers often block access to the selection of codecs in the standard settings menu. They believe that the average user should not interfere with technical parameters in order not to encounter connection problems. That is why we will need special access methods to change the settings.
⚠️ Attention: Forcing a codec that is not supported by your headphones at the hardware level will lead to a complete lack of sound or constant disconnections.
Understanding the principles of operation Bluetooth stack in Android helps you understand why simple switches in the menu often absent. The system dynamically controls the data flow, and rigidly fixing parameters can upset this balance.
Checking codec support on your device
Before you start setting up, you need to make sure that your equipment is physically capable of working with improved formats. Not all smartphones and headphones are equipped with the appropriate chips. For example, the technology LDAC was originally developed by Sony, although it is now available on many devices with Android 8.0 and higher.
To check support, you can use third-party applications from the store Google Playsuch as Bluetooth Codec Checker or Material Bluetooth Scanner. These utilities read information directly from the Bluetooth module and display a list of all available encoding algorithms.
- 📱 Install the application for checking codecs from the official store.
- 🎧 Connect your wireless headphones to your smartphone.
- 🔍 Start scanning and find section Supported Codecs.
- ✅ Compare the list with what your headphones offer in the specification.
If the list contains aptX Adaptive or LDAC, then success is possible. Otherwise, software manipulations will not add the missing functions, since they require a specific decoder on the chip.
Please note that even with LDAC support, sound quality may depend on the distance to the smartphone and the presence of obstacles between devices.
Activating the developer menu to change the codec
The easiest and safest way to change sound settings is to use the built-in menu for developers. This section is hidden from the eyes of ordinary users, but contains many useful tools for fine-tuning the system, including selecting a Bluetooth audio codec.
To activate this mode, you need to go to the section Settings → About phone and find the item Build number. Click on it quickly 7 times in a row. The system will notify you that you have become a developer, and a new section will appear in the main settings menu For developers.
Inside this menu, you need to scroll down the list to the "Network" section or "Multimedia". There you will find the item Bluetooth Audio Codec. By clicking on it, you will see a list of available options. By default, “System Default” is selected there, but you can manually select the desired format.
Settings → For Developers → Bluetooth Audio Codec → LDACIf you select an unsupported codec, the sound simply will not work, and you will have to restart Bluetooth or choose another option.
☑️ Activating the developer menu
Advanced setup through the engineering menu
For users for whom the standard settings are not enough, there is access to the engineering menu. This interface allows you to change in-depth radio parameters, including bitrate and sample rate for high-definition codecs. Access to it varies depending on the processor manufacturer (MediaTek, Qualcomm, Exynos).
Most often, login is done through a special application Engineering Mode or by entering the USSD code in the dialer. For example, for many devices based on MediaTek the code works ##3646633##. After logging in, you need to go to the tab. Hardware Testing, then Audio and Bluetooth Audio.
Here you can find settings for specific profiles, such as A2DP (Advanced Audio Distribution Profile). In this section, you can force the desired bitrate, for example, 990 kbps for LDAC, instead of automatic. selection. This gives maximum quality, but requires ideal signal reception conditions.
⚠️ Attention: Changing parameters in the engineering menu may lead to unstable operation of the Bluetooth module or loss of sound. Write down the initial values before making changes.
Some manufacturers block access to the engineering menu in the latest firmware versions. In such cases, this method may not work without. obtaining root access or installing special patches.
What to do if the code does not work?
If standard USSD codes do not open the engineering menu, try installing the 'MTK Engineering Mode' application from third-party sources. However, be careful: download software only from proven ones. repositories to avoid infecting the device with malware.
Using ADB to force a change in settings
If the graphical interface does not give the desired results, you can use the debug tool ADB (Android Debug Bridge) (This method requires connecting the smartphone to the computer via a USB cable and having drivers and platform tools installed on it). PC.
First you need to enable “USB Debugging” in the developer menu on your phone. Then, after connecting the device to your computer, open the command line or terminal. Using the command adb devices make sure that the smartphone is detected by the system.
To change the codec, the global settings command is used. The syntax may differ depending on the system. version of Android, but the general principle is to change the property persist.bluetooth.audiocodec. This allows you to set the priority codec at the system level, ignoring standard selection algorithms.
adb shell settings put global bluetooth_a2dp_codec_priority 5Where the number corresponds to the codec priority in the system list (usually LDAC has a high priority, this method is considered the most reliable for advanced users, since it makes changes directly to the system settings tables.
It is worth noting that after rebooting the device, some settings made via ADB may be reset. In this case, you will need to create an automation script or repeat the procedure.
Using ADB gives maximum control over the system, but requires caution: one incorrect command can disrupt the operation of the Bluetooth stack until the settings are completely reset.
Comparison of popular Bluetooth codecs
To make an informed choice, you need to understand the differences between the available audio transmission formats. Each codec has its own advantages and disadvantages, which manifest themselves in different usage scenarios: listening to music, watching videos or playing games.
Basic SBC Provides acceptable quality for podcasts and calls, but heavily compresses the music signal, cutting off high frequencies. AAC Works better with Apple devices, providing good compression efficiency at low bitrates. However, on Android its implementation is often inferior in quality. Qualcomm's technologies offer a balance between quality and latency, making them ideal for watching videos. The leader in data transfer quality is
Technologies aptX And aptX HD from Qualcomm offer a balance between quality and latency, making them ideal for watching videos. The leader in data transmission quality is LDAC, capable of transmitting 3 times more data than a standard SBC, approaching CD-quality parameters.
| Codec | Max. bitrate | Bit depth/Frequency | Best application |
|---|---|---|---|
| SBC | 328 kbps | 16 bit / 44.1 kHz | Universal, calls |
| AAC | 256 kbit/s | 16 bit / 44.1 kHz | Apple devices, streaming |
| aptX HD | 576 kbit/s | 24 bit / 48 kHz | Hi-Res music, video |
| LDAC | 990 kbit/s | 24 bit / 96 kHz | Audiophile listening |
| LHDC | 900 kbit/s | 24 bit / 96 kHz | Flagship smartphones |
The choice of a specific codec should depend on your priorities. If connection stability in the subway or on the street is important, it is better to choose aptX Adaptive, which dynamically changes the bitrate. To listen to FLAC files at home without interference, the ideal choice would be LDAC in quality priority mode.
When using high-definition codecs (LDAC, LHDC), the battery life of the headphones may be reduced by 15-20% due to the increased load on the processor and radio module.
Possible problems and their solution
Even with proper setup, users may experience audio artifacts, crackling noises, or intermittent disconnections of the headphones. This is often due to the selected bitrate being too high for the current radio signal conditions. In such cases, the system does not have time to transfer the entire amount of data.
The first step to solving the problem is to reduce the quality priority in the codec settings. For example, in the settings menu LDAC you can select the “Stable connection priority” mode instead of “Sound quality priority”. This will lower the bitrate, but eliminate tearing.
It's also worth checking to see if there are any network or Bluetooth-heavy apps running in the background, as they may cause interference. Overheating of the smartphone can also affect the operation of the Bluetooth module, reducing the transmitter power.
⚠️ Attention: Settings interfaces and menu item names may differ depending on the version of Android and the manufacturer’s shell (MIUI, OneUI, ColorOS). Always check the latest documentation for your model.
If all else fails, try “forgetting” the device in the Bluetooth settings and pairing again. Sometimes the cache of old settings prevents the correct negotiation of codec parameters when connecting again.
Why did the sound become quieter after changing the codec?
This may be due to differences in the amplification algorithms of different codecs. Some drivers do not adjust the volume level when switching to more efficient codecs. Try increasing the volume in the settings of the smartphone itself or in the player application.
Can LDAC be used on older smartphones?
Officially, LDAC support appeared in Android 8.0 Oreo. On older versions of the system, this codec is not available at the OS level. However, there are third-party modules for Magisk (if you have root access) that can add this function, but stability is not guaranteed.
Does changing the codec affect the sound delay in games?
Yes, it does. High resolution codecs such as LDAC typically have higher latency due to the complexity of signal processing. For games, it is better to use codecs with low latency, for example aptX Low Latency or aptX Adaptiveif they are supported.
Are codec settings reset after a reboot?
Settings changed through the developer menu are usually saved. However, settings made through the engineering menu or ADB without being pinned to the system may be reset to default values after rebooting the device.
Why doesn’t my phone see the aptX HD codec?
For aptX HD to work, support is required from both the smartphone (Qualcomm chip with the appropriate license) and the headphones. If at least one device does not support this standard, it will not appear in the list of available codecs.