Modern users are increasingly abandoning wires in favor of free movement, and the smartphone Xiaomi Redmi 9 does an excellent job of managing wireless peripherals. However, the first pairing process may raise questions for those who have not previously used the technology Bluetooth on devices with shell MIUI. Correctly setting up the data transmission channel guarantees not only a stable connection, but also high quality sound without delays.
In this article we will analyze in detail each stage of interaction between your phone and the headset, from activating visibility mode to fine-tuning audio codecs. You will learn how to avoid common connection errors and what to do if the gadget does not see the headphones. The information will be useful both to owners of new accessories and to those who are trying to restore communication with previously used devices.
Preparing equipment and activating Bluetooth
Before starting the procedure, you must make sure that both devices are ready for interaction. The smartphone Redmi 9 must have sufficient battery power, since the search and pairing process consumes a significant amount of energy. Also make sure your headphones are fully charged, as many models automatically turn off when the battery level is low, interrupting the pairing process.
On a smartphone, the wireless module is activated through the notification panel or system settings. The fastest way is to swipe down from the top of the screen to open notification curtainand find the icon that looks like a stylized letter "B". Click on it so that it lights up with the active color. If the icon is not in quick access, you will need to go to the deep settings menu.
For more detailed control, go to the section Settings → Bluetooth. Here you will see a switch at the top of the screen. Make sure it is in the Enabledposition. The system will automatically begin scanning available devices within range, however, for successful connection, the external headset must be in a special standby mode.
⚠️ Attention: Make sure that your headphones are not currently connected to another smartphone or tablet. Many models TWS (True Wireless Stereo) automatically reconnect to the last used device, ignoring the new request from Redmi 9.
Interface MIUI on Redmi 9 displays a list of found devices in real time. If the list is empty, although the headphones are turned on, try updating it by clicking on the update icon next to the list, or temporarily turn Bluetooth off and on again on your phone. This will reset the search cache.
If the Bluetooth icon is gray and not clickable, try turning Airplane mode on and off in the notification shade. This will restart all radio modules of the smartphone.
Putting the headphones into pairing mode
The most critical stage, where most mistakes are made, is incorrectly entering the headset into (pairing) mode. Simply turning on your headphones is often not enough; they must clearly signal to the phone that it is ready for a new connection. The mechanics of this process vary depending on the design type of your headphones.
For full-size over-ear models or headsets with a neckband, you usually need to hold down the power button or a special button with the Bluetooth logo. Hold it down for 5-7 seconds until the indicator starts flashing red and blue alternately. It is this pulsation that means that the device is in the mode visibility for all surrounding gadgets.
- 🎧 Power button: press and hold until a flashing indicator appears (often it takes longer than just turning it on).
- 🔋 TWS case: open the lid of the charging case with the headphones inside and hold down the button on the back panel (or inside the case) until the indicator flashes white.
- 👆 Touch control: some models require simultaneous pressing of two touch zones on the headphones themselves for 3-5 seconds.
Owners of completely wireless headphones TWS should be more careful with the case. If you take the headphones out of the case, they may try to connect to each other rather than to the phone. In this case, put them back, hold down the button on the case, and only after the indicator starts blinking, take them out for use.
⚠️ Attention: The visibility mode often lasts for a limited time (about 1-2 minutes). If during this time you did not have time to click on the device in the phone menu, the procedure for switching to pairing mode will have to be repeated again.
Pairing process in the MIUI interface
As soon as the indicators on the headphones indicate readiness, refer to the screen of your Redmi 9. Your model name should appear in the Available Devices list. It may coincide with the brand (for example, Sony, JBL) or contain a technical index. Click on the device name to begin the authorization procedure.
The Android system initiates the exchange of encryption keys. In most cases, no additional action is required and the status will change to “Connected” in a few seconds. However, some models may ask you to confirm your PIN. The standard code for devices is 0000 or 1234, but this information is always in the manufacturer's instructions.
After a successful connection, the Bluetooth icon in the status bar may change shape or a small headphone icon will appear next to it. This means that the audio stream is now routed to the external device. You can launch any media player or YouTube video to check for sound.
Settings → Bluetooth → Click on the gear next to the device → Toggle “Media Audio”If the connection is successful, but there is no sound, check the connection profile. In some rare cases, the phone only connects the Phone Calls profile, ignoring media. Go to the settings of a specific device in the Bluetooth list and make sure that the checkbox next to the item Media audio is active.
☑️ Checklist for successful connection
Setting the sound quality and codecs
For advanced users who want to get the most out of a combination of Redmi 9 and high-quality acoustics, it is important to understand the operation of audio codecs. The standard codec SBC provides basic quality, but for Hi-Res audio it is better to use aptX, aptX HD or LDACif your headphones support them.
The smartphone's processor and communication module automatically negotiate the best possible codec when connected. However, you can check and force select a profile through the engineering menu, although this function is often hidden in the standard MIUI shell. You can use third-party utilities from the Play Market, such as Bluetooth Codec Changerto view the current connection parameters.
| Codec | Bitrate (approximate) | Latency | Compatibility |
|---|---|---|---|
| SBC | 328 kbit/s | High | Universal |
| AAC | 256 kbit/s | Medium | iOS, Android |
| aptX | 352 kbit/s | Low | Qualcomm chips |
| LDAC | 990 kbit/s | Variable | Sony, Android 8+ |
Use of high-resolution codecs such as LDAC, can significantly increase the battery consumption of both the smartphone and headphones due to the increased volume of transmitted data. If you notice that the charge is draining too quickly, it makes sense to return to standard AAC or SBC in the developer settings.
How to enable the developer menu to configure codecs?
Go to Settings → About phone. Quickly click on the “MIUI Version” item 7-10 times in a row until the message “You have become a developer” appears. Then, in the advanced settings, find the “For Developers” section and the “Bluetooth Audio Codec” item.
Troubleshooting problems with connection and sound
Even with the correct sequence of actions, failures may occur: intermittent sound, desynchronization of audio and video, or a complete failure of the system to see the device. Most often, the problem lies in a software conflict or an accumulated cache of the Bluetooth service at the level of the Android operating system.
The first step in diagnosis is to completely clear the list of paired devices. Go to Bluetooth settings, click on the gear next to the problematic headphones and select Cancel pairing or “Forget device”. After this, restart your smartphone and try connecting from scratch, as described in the previous sections.
- 🔄 Reset network: go to
Settings → Connectivity and sharing → Reset Wi-Fi, mobile network and Bluetooth. This will remove all saved networks and devices, but often resolves underlying driver conflicts. - 🔋 Energy saving: turn off power saving mode on Redmi 9. Aggressive Battery optimization can “kill” the audio process in the background.
- 📶 Interference: Make sure there are no thick walls or operating microwave ovens between the phone and the headphones that create interference in the 2.4 GHz band.
If the sound is interrupted only in certain applications, check their individual settings. Some instant messengers or players have their own audio output switches. It is also worth making sure that in the accessibility settings the mono sound or balance functions are not activated, which can distort the perception of the stereo image.
⚠️ Warning: The “Absolute volume level” function in the developer menu sometimes causes conflicts when the volume on the phone and headphones is out of sync. Try disabling this item if the volume control behaves incorrectly.
In 90% of cases, the connection problem is solved by completely removing the device from the phone's memory and re-pairing it with a switched off Wi-Fi module to reduce radio interference.
Features of working with multiple devices
A smartphone Redmi 9 allows you to store many devices in memory, but you can usually only transmit an audio stream to one pair of headphones at the same time. However, modern Bluetooth standards support the Multipoint function, which allows the headset to connect to two signal sources simultaneously.
If you want to use headphones with both your phone and laptop, make sure that this feature is supported by the headset itself. The smartphone settings are secondary here. When actively connected to Redmi 9, an incoming call on the second device can automatically pause the music on the phone if the multipoint is configured correctly.
To switch between previously paired devices, it is not necessary to go to the menu every time. It is enough to turn off Bluetooth on the current active device, and the headphones (with auto-reconnection support) will automatically find the next available gadget from the memory list. On Redmi 9, you can quickly switch through the notification shade by long-pressing the Bluetooth icon.
Give devices meaningful names. Go to the Bluetooth device settings on Redmi 9 and rename it (for example, “My Sony”). This will simplify the choice in the future if you have a lot of gadgets.
Why does the phone see the headphones, but does not connect?
Most often, this means that the headphones are already connected to another device nearby. The Bluetooth protocol prioritizes the active connection. Disable Bluetooth on other gadgets or perform the “Forget Device” procedure on them.
Is it possible to connect two pairs of headphones to one Redmi 9?
Standard Android and MIUI tools on Redmi 9 do not support simultaneous audio transmission to two different pairs of Bluetooth headphones. This requires special external transmitters or features that are only available on flagship models that support Dual Audio.
How to increase the volume if it is too quiet?
Check if the "Absolute Volume" mode is enabled in the developer menu (try toggling it). Also make sure that the “Hearing Safety” function is not activated in the sound settings, which limits the maximum volume.
Does the case affect the call quality?
Yes, massive cases with metal inserts or a thick layer of rubber can shield the Bluetooth antenna located on the top of the Redmi 9. If the connection is interrupted, try removing case for testing.
What to do if the left earphone does not work?
In TWS headphones, this is a common problem of desynchronization of the right and left channels. Place both headphones in the case, hold down the reset button for 10-15 seconds until the indicator color changes, then remove the device from the phone’s memory and connect again.