No sound when broadcasting from phone to TV Xiaomi: a full analysis of causes and solutions

Broadcasting a smartphone screen to a big screen on a Xiaomi TV should be a simple process — plugged in, selected the source, and everything works. But what if the picture is there and the sound is lost or distorted? This problem occurs in users of different models — from budget Mi TV A2 to flagship Xiaomi OLED Vision, and the reasons for it can be a dozen, most often due to the wrong settings of the phone, conflicts of data protocols or hardware limitations of the devices themselves.

In this article, we'll look at all the possible scenarios for why sound isn't transmitted when broadcasting, from the common Miracast bugs to the specific MIUI firmware bugs, how to diagnose a problem by symptoms, what parameters to check first, and what to do if standard methods don't work, and finally, answers to frequent questions and life hacks for stable operation.

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1. Checking the basic settings: what could have gone wrong

Before digging deep into firmware settings or updating software, make sure that the problem is not in the obvious trivia. 60% of the time, the sound is lost due to an incorrect signal source or a switched off sound on one of the devices.

Start with the Xiaomi TV:

• 🔊 Volume level: press Volume+ on the remote, maybe the sound is just turned off or set to a minimum, and check if the Mute mode is activated.
• 📺 Signal source: If you connect via HDMI, select the appropriate port in the Source menu (Source button on the remote). For wireless broadcast (Miracast/AirPlay), select Screen Mirroring or Wireless.
• 🔄 Sound Mode: In the TV settings (Settings → Sound) check to see if Night Mode or Dynamic Range is activated, which can suppress sound when broadcasting.

Now, let’s move on to the smartphone:

• 📱 Media Volume: On Android, volume control for multimedia and calls is split. Make sure the Media slider (not the Call) is not at zero.
• 🚫 Do Not Disturb Mode: If it's on, the sound can be blocked. Check in the notification curtain or in Settings → Sound.
• 🔗 App Permissions: If you stream through YouTube, Netflix, or another app, make sure it has access to the microphone and speakers (in Settings → Apps → Permissions).

⚠️ Warning: On some Xiaomi models (e.g., Redmi Note 10 Pro) when connected via HDMI via an adapter USB-C → HDMI, the default sound can only be transmitted via a smartphone. To redirect it to TV, pull the notification curtain and tap the HDMI notification — there should be a switch to output sound.

2. Problems with broadcast protocols: Miracast vs. HDMI vs. Bluetooth

Sound may be missing because of protocol incompatibility or malfunction, so let's look at each connection separately.

Miracast (Wireless Display) is the most common way to broadcast wirelessly, but also the most problematic:

• 📶 Latency or absence of sound: Miracast transmits video and audio over separate channels. If the router is overloaded or the signal is weak, the sound may lag or disappear. Try reconnecting to a 5 GHz network (it is more stable than 2.4 GHz).
• 🔧 Sound Codecs: Some Xiaomi TVs do not support modern audio codecs (e.g., LDAC or aptX). In the smartphone developer settings (Settings → About Phone → Build Number – tap 7 times), select Bluetooth Audio Codec and set SBC (most versatile).
• 🚫 Lock DRM: If you are broadcasting secure content (Netflix, Disney+), the sound may be missing due to limitations HDCP. Try another source (e.g. local video).

HDMI (wired connection) is usually more reliable, but there are nuances:

• 🔌 Cable or adapter: Cheap adapters USB-C → HDMI often don't support audio transmission. Use certified accessories (e.g., the original Xiaomi USB-C to HDMI).
• 🎵 Sound format: In the TV settings (Settings → Sound → Sound Format HDMI), set PCM instead of Dolby Digital – the latter may not be supported by a smartphone.

Bluetooth – if you connect your phone to your TV as a separate speaker:

• 🔗 Connection Profile: Make sure the TV is connected in A2DP mode (for music) and not HFP (for calls). In your smartphone's Bluetooth settings, check that the Media Audio tick is active.
• 🔄 Reconnect: Sometimes it helps to “forget” the device at both ends and reconnect.

3. Android Sound Settings: Where to Look for a Problem

If the basic checks didn't work, it's time to look into Android's deep settings, and often the sound goes missing because of system conflicts or manufacturer constraints.

Sound redirection:

• 🔊 The notification curtain when you connect to HDMI or Miracast should show a notification with a choice of audio output device. If it is not, the sound goes through the phone's speakers. On some firmware MIUI this notification is hidden: open Settings → Connected devices → Connect to TV and manually select Xiaomi TV.
• 🔧 If the option is not available, activate Developer Mode and enable Debugging on HDMI (Settings → System → Developer).

Manufacturer's restrictions:

• 🚫 On some Xiaomi models (e.g., POCO X3), when connected via Miracast, the sound is automatically blocked to save battery power. Turn off this feature in Settings → Battery → Battery → Battery Optimization (find the broadcast app and select Without Limits).
• 🔒 If you use Netflix or Amazon Prime, the sound may be missing due to Widevine L1. Check the security status in the DRM Info app (available on Google Play).

Application conflicts:

• 🎬 Some applications (e.g., VLC or MX Player) have their own audio output settings. In the player menu, search for the Audio → Output option and select HDMI or Bluetooth.
• 🔄 If there's sound in some applications but there's not in others, the problem is the software itself. Try updating it or using an alternative.

4. firmware updates: why they can break sound

On Xiaomi TVs with firmware older than 2022 (for example, Mi TV 4S 55) there is a bug in which after the update the sound disappears when broadcasting on Miracast due to the reset of DRM certificates.

How to check the firmware version:

1. On TV: Settings → About TV → System Update.
2. On the smartphone: Settings → About the phone → MIUI version.

What to do if the sound is gone after the update:

• 🔄 Firmware rollback: If the problem occurs after an update, try going back to the previous version. On TV, you can do this via Settings → Update → System Restore (you need a USB- firmware drive).
• 🔧 Reset certificates DRM: on your TV, go to Settings → Apps → All apps → Google Play Services → Storage → Clear data. After that, restart the TV and connect again.
• 📥 Manual patch installation: Developers sometimes post patches for specific models on the 4PDA or XDA forums. Look for themes marked [FIX] Miracast audio.

⚠️ Warning: If you decide to roll back the TV firmware, only use official files from Xiaomi. Installing custom firmware can lead to loss of warranty and irreversible errors in the operation of HDMI- ports.

5. Hardware problems: when the "iron" is to blame

If the software didn't work, it might be physical malfunctions, and here are the most common hardware causes of the lack of sound:

Problems with HDMI- port or cable:

• 🔌 Contact oxidation: If the HDMI port on the TV or adapter is contaminated, the sound may be distorted or not transmitted at all.
• 🔄 Damaged cable: Even an externally complete cable can have internal cliffs. Try another cable that supports HDMI 2.0 ARC (it transmits sound in both directions).

Faulty of the TV speakers:

• 🔊 Speaker check: connect another sound source to the TV (e.g., Bluetooth speaker or 3.5mm jack if you have one). If there is no sound there, there is a problem with the TV audio track.
• 🛠️ Diagnostics in the service menu: on the remote, click Menu → Settings → All Settings → General → Device Preferences → About → Enter the 9999 code (for some models).

Smartphone problems:

• 📱 USB-C/3.5mm connector: If you connect through an adapter, check if the phone connector is contaminated. Use a flashlight to inspect the contacts for damage.
• 🔋 Power Saving Mode: Some Xiaomi models (e.g. Mi 11) turn off "non-critical" functions, including sound transmission over HDMI, when battery power is low. Connect the phone to charge and try again.

6. Alternative methods of sound transmission

If the standard methods don't work, you can go roundabouts. Here are 3 working ways to bring back sound when broadcasting:

1. Use of an external audio device:

• 🎧 Connect the Bluetooth speaker or headphones directly to the TV, and the sound will go through them, and the picture will go from the phone.
• 🔊 If the TV has a 3.5mm output or optical output, plug in the active speakers.

2. broadcasting sound separately from video:

• 📱 On your smartphone, turn on Developer Mode and activate Separate Audio (Settings → System → Developer → Separate Audio) to output audio to the Bluetooth headset and video to TV.
• 🎵 Use applications like SoundWire or AudioRelay that transmit audio from your phone to your PC/column over a local network.

Programmatic workarounds:

• 🖥️ If you are streaming from Windows via Miracast, select the TV as the default output device in Sound Settings.
• 📺 On your TV in Sound → Output HDMI, install Bitstream instead of PCM if the sound is distorted.

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If there is a sound, but with a delay (lag), try in the settings of the TV (Settings → Sound → Lip Synchronization) manually adjust the delay in the range of 0-300 ms.

7. When to contact the service center

If you've tried all the ways and the sound never came, you might need professional intervention, and here are the signs that it's time to get the equipment repaired:

Symptoms of hardware malfunctions:

• 🔌 The sound is lost on any connection (including HDMI, Bluetooth, and optical output).
• 🔊 Television speakers make crackles or hisses even without a smartphone connection.
• 📺 Artifacts (strips, flickering) appear on the screen at the same time as the sound disappears.

What's on the service?

• 🛠️ Audio tract: track integrity on the motherboard, sound amplifier operation.
• 🔧 HDMI- port: soldering of contacts, presence of microcracks.
• 📡 Wi-Fi/Bluetooth- Module: If the problem is only with wireless broadcasting.

⚠️ Warning: If the TV is warranty, do not open it yourself - this will void warranty obligations. Contact the authorized Xiaomi service center with a check and a product passport.

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Before visiting the service, make a factory reset (Settings → System → Reset) in 10% of cases, this solves the problem, saving you time and money.

FAQ: Frequent questions about broadcast sound