# Why can't I hear audio in stereo when playing a stereo file? (/en/api-reference/faq/integration/no_stereo_audio)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

When calling `startAudioMixing` or `playEffect` to play a stereo file, the user might encounter the issue of not being able to hear audio in stereo.

## Reason [#reason]

If you cannot hear stereo audio, the possible reasons are as follows:

* The audio file being played is not a stereo file.
* Stereo encoding is not set in the Agora SDK.
* The audio playback device does not support stereo audio.

## Solution [#solution]

To troubleshoot and solve the issue, do the following:

### Step 1: Check the audio file [#step-1-check-the-audio-file]

Check whether the audio file is a stereo file by viewing the audio signal.

* If the audio file has only a mono audio signal, or if the audio file has dual audio signals but the audio signals of the left and right channels are the same, the audio file is not a stereo file. Change the file to a stereo file.
* If the audio file has dual audio signals and the audio signals of the left and right channels are different, the audio file is a stereo file. Proceed to step 2 to check the SDK settings.

### Step 2: Check the SDK settings [#step-2-check-the-sdk-settings]

The SDK can correctly encode and transmit stereo audio only when you set the stereo encoding. Check whether you call `setAudioProfile` and set the `profile` parameter to `AUDIO_PROFILE_MUSIC_STANDARD_STEREO` (3) or `AUDIO_PROFILE_MUSIC_HIGH_QUALITY_STEREO` (5).

* If a stereo profile is not set, set the `profile` parameter correctly.
* If the profile is set correctly, proceed to step 3 to check the audio playback device.

### Step 3: Check the audio playback device [#step-3-check-the-audio-playback-device]

Check whether the device supports stereo audio, and check whether the device is working properly.

* If the device does not support stereo audio, change it to a device that supports stereo audio.
* If the device supports stereo audio but does not work properly, contact the device manufacturer for repair or change it to a device that works properly.
* If the device supports stereo audio and works properly, [submit a ticket](https://agora-ticket.agora.io/) to contact Agora customer support for further exploration of the issue.

<CalloutContainer type="info">
  <CalloutDescription>
    If you use a Bluetooth device to play audio, note the Bluetooth profile. The two common profiles are as follows:

    * **Advanced Audio Distribution Profile (A2DP):** The unidirectional transmission of high-quality audio data, usually for stereo music playback. A2DP does not support capturing audio through the Bluetooth device, so you need to use other devices to capture audio.
    * **Hands-Free Profile (HFP):** The bidirectional transmission of audio data, usually for audio calls. HFP commonly uses Synchronous Connection Oriented link (SCO) to carry a mono audio channel, so a Bluetooth device cannot play stereo audio using HFP.
  </CalloutDescription>
</CalloutContainer>