Modern Xiaomi TVs with Android TV offer excellent image quality, but the built-in acoustics often yield to the requirements of moviegoers. The thin body limits the size of the speakers, which loses low frequencies and volume of sound. The solution to this problem is an external acoustic system that will unlock the potential of the video sequence.
One of the most reliable ways to transmit audio is to use an optical cable Toslink. Unlike HDMI, this interface does not transmit a video signal, but provides stable digital audio transmission without interference and delay, which is the method of connection that many users prefer to create a home theater.
In this article, we will discuss in detail the process of connecting a Mi TV or Redmi TV to a soundbar via the SPDIF port. You will learn about choosing the right cable, adjusting the audio output format and solving typical problems when the sound is missing or not working correctly.
Selection of equipment and cable preparation
Before installing, make sure that the appropriate connectors are available on both devices. On the back or side of a Xiaomi TV, you should find a port signed as SPDIF or Optical. This connector is square in shape and often has a protective plug that must be carefully removed before connecting.
The soundbar should also be equipped with a similar input.Combined with Xiaomi acoustic systems such as Mi Soundbar or Xiaomi TV Soundbar, often the necessary cable is about 1.5 meters long.If it is not, you will need to purchase a separate fiber optic cable standard Toslink.
⚠️ Warning: The optical cable contains a brittle fiberglass inside the plastic shell. Do not bend it at a sharp angle or squeeze it, as this will cause the fiber to rupture and loss of signal.
The quality of the cable itself plays a secondary role for short distances, but for distances over 5 meters, it is better to use models with reinforced coating. Cheap cables can have poorly polished ends, which reduces the efficiency of the light signal transmission.
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Check the integrity of the optical cable before buying: shine a flashlight on one end – the other should be visible light.
Process of physical connection of devices
The process of connecting equipment is as simple as possible and requires no special technical skills, the main thing is to follow a sequence of actions to avoid short circuits or damage to ports, although the optical interface is protected from electrical surges.
First, you have to completely shut down the TV and the soundbar, so that static electricity doesn't damage the sensitive photodetectors in the ports, and then you can switch off the socket.
- 🔌 Insert one end of the optical cable into the Optical Out port on the Xiaomi TV before the characteristic click.
- 🔊 Connect the second end of the cable to the Optical In connector on the back of the soundbar.
- 🔋 Turn both devices on to the electrical network and run them with power buttons.
When you turn on, the soundbar usually automatically goes into standby mode, the LED lights may light up on the indicator, signaling readiness to work, and if you use the acoustic remote control, make sure that the source of the OPT or Optical signal is selected.
☑️ Checking the physical connection
Customization of sound parameters in MIUI TV
After a physical connection, it is critical to properly configure the TV's software part. By default, Xiaomi TV can try to output audio through built-in speakers or Bluetooth, ignoring the connected optical output.
To change the settings, go to the main menu and select the settings section. The path may vary slightly depending on the firmware version, but the logic remains the same for all Android TV devices.
You need to find Settings, then go to Sound or Display & Sound. Inside this menu, look for Digital Output or Digital Output, and that's where the data stream switches to an external port.
In the list that opens, select Pass-through or Auto. Pass-through mode allows the TV to stream the original audio stream without processing to a soundbar that decodes formats like Dolby Digital itself.
Why can the sound be quiet?
Choosing the audio stream format and codecs
The sound quality depends on the coding format chosen. The optical cable has enough bandwidth for most compressed multichannel formats, but is inferior to HDMI ARC in supporting the latest codecs without compression.
Xiaomi TV audio settings often offer a choice between PCM and RAW (or Bitstream).For soundbars that support Dolby Digital decoding, RAW or Bitstream mode is the best choice.
If you choose a PCM, the TV will decode the sound itself in stereo or compressed multi-channel format, which can lead to loss of surround sound quality in movies, in which case the Soundbar will receive a ready-made, but less high-quality signal.
| Format | Quality. | Soundbar support | Recommendation |
|---|---|---|---|
| PCM Stereo | Basic | All devices. | For old TVs. |
| Dolby Digital | 5.1 Surround | Most soundbars | Optimal for optics. |
| DTS | 5.1 Surround | Depends on the model. | For compatible systems |
| Dolby Atmos | 3D Sound | Only through HDMI. | Not supported by optics |
Dolby Atmos format is not transmitted via optical cable due to bandwidth limitations of the interface. S/PDIF. To get a full Atmos, you need to use it. HDMI ARC/eARC.
Solving problems with lack of sound
Sometimes, after you've done all the settings, the sound doesn't appear, which is a common situation that can be caused by a software failure or the wrong source choice on the soundbar itself.
First, check if the TV is set to mute or minimum volume. Then make sure the audio settings select the output device "Optical output" or "External speakers" rather than "Dynamic TV".
A common problem is sampling frequency incompatibility. Some old soundbars can't decode a signal above 48 kHz. In this case, Xiaomi's TV settings should manually set the frequency to 48,000 Hz or 44100 Hz.
⚠️ Warning: If you hear a crack or interruption when you switch channels, try replacing the optical cable.
Also, a complete system reboot helps: pull the TV power cord from the socket for 1-2 minutes to reset the system cache and initialize the ports again.
Use of Xiaomi’s universal remote
One of the advantages of Xiaomi’s ecosystem is that it can control the soundbar with a regular TV remote, eliminating the need to hold two different controls.
To activate this feature, go to Accessories or Bluetooth and Devices in the TV settings. Select the option to add a new device and find your soundbar model in the list of infrared remotes.
The system will suggest testing the buttons, and if the soundbar responds to the test signals, save the settings, and then the volume and the acoustics will be controlled by the main remote control.
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The infrared port of the TV should "see" the soundbar receiver for the universal remote, so do not glue the front panel with decors.
Comparison of optical connectivity and HDMI ARC
Users often wonder: which is better to use, optics or HDMI? Each method has its own advantages, and the choice depends on the age of your technique and the specific requirements for sound quality.
The optical cable provides electrical decoupling, which completely eliminates the tips and backgrounds typical of analog connections, and is compatible with almost all audio equipment produced in the last 20 years.
HDMI ARC (Audio Return Channel) allows you to transmit more advanced sound formats, including the object-oriented Dolby Atmos, and control volume without a separate setup.
- 📉 Optics do not support video transmission, only audio.
- 🔊 HDMI ARC Allows you to use one remote for all functions without configuring IR codes.
- ⚡ Optical cable does not require handshake protocols, which reduces the likelihood of conflicts HDCP.
If your soundbar and TV support HDMI ARC, it makes sense to try this option, but if you're facing problems syncing sound and image, going back to optical cable is the most reliable solution.