# Configure mixer settings for audio capture

Source: [https://docs.qualcomm.com/doc/80-88500-3/topic/25_Configure_mixer_settings_for_audio_capture.html](https://docs.qualcomm.com/doc/80-88500-3/topic/25_Configure_mixer_settings_for_audio_capture.html)

Configuration of audio volume and channel numbers is the prerequisite to enable the audio capture
      or playback. These settings are set through `controlC0` under
        /dev/snd. The `controlC0` node is called ALSA mixer
      control, and the settings are called Mixer settings.

Set the mixer parameters in the third digital MIC (DMIC) on the QRB5165 board according to the
      requirement. A sample setting is shown in the following table:

| Features | Commands | Values |
| --- | --- | --- |
| Channel number | `amixer cset name='TX_CDC_DMA_TX_3 Channels' 'One'` | Set DMA channels as 1 |
| Volume | `amixer cset name='TX_DEC2 Volume' 84` | Set volume as 84 |
| Audio path | `amixer cset name='Tx DEC2 MUX' 'MSM_DMIC'` | Select decimator 2's source from DMIC |
| Audio path | `amixer cset name='Tx DMIC MUX2' 'DMIC2'` | Select second DMIC as audio source |
| Audio path | `amixer cset name='TX_CDC_DMA_TX_3 SampleRate' 'KHZ_48'` | Set sample rate as 48 kHz |
| Audio path | `amixer cset name='TX_CDC_DMA_TX_3 Format' 'S16_LE'` | Set audio sample format as signed 16 bit and little endian data |
| Audio path | `amixer cset name='TX_AIF1_CAP Mixer DEC2' 1` | Select audio interface 1's source from decimator 2 |
| Audio path | `amixer cset name='MultiMedia1 Mixer TX_CDC_DMA_TX_3' 1` | Select audio DAI source from TX\_CDC\_DMA\_TX\_3 |
|  |  |  |
|  |  |  |
|  |  |  |
|  |  |  |
|  |  |  |

See the mixer\_paths\_iot.xml file on the QRB5165 device in the
        /etc directory for details on how to choose the right settings. After
      setting up mixer settings, access the correct audio device node to start streaming.

**Parent Topic:** [Configure audio settings](https://docs.qualcomm.com/doc/80-88500-3/topic/18_Configure_audio_settings.html)

Last Published: Sep 26, 2023

[Previous Topic
Configure device node in ALSA interface](https://docs.qualcomm.com/bundle/publicresource/80-88500-3/topics/24_Configure_device_node_in_ALSA_interface.md) [Next Topic
Convert audio HAL use cases into ALSA mixer controls](https://docs.qualcomm.com/bundle/publicresource/80-88500-3/topics/27_Convert_audio_HAL_use_cases_into_ALSA_mixer_controls.md)