> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Audio

The IQ-9075 audio subsystem is powered by Low Power AI (LPAI) and delivers advanced voice UI and audio experiences via PipeWire.

## Key Features

* **Low Power AI (LPAI)** subsystem for efficient audio processing
* **PipeWire** multimedia server for low-latency audio routing
* **Hardware-accelerated** encoding/decoding
* **Fluence ECNS** — advanced echo cancellation and noise suppression
* **Multiple audio interfaces** — I2S, TDM, SoundWire

## Hardware Configuration

<img src="https://mintcdn.com/qualcomm-prod/Bh7DlgudKfjY_3Wf/Linux/images/peripheral-interfaces/audio-components.png?fit=max&auto=format&n=Bh7DlgudKfjY_3Wf&q=85&s=cc3bab53dac8725d501529ef0460c482" width="1208" height="526" data-path="Linux/images/peripheral-interfaces/audio-components.png" />

* **Speakers:** Onboard speakers with MAX98357 I2S-amps; HS0\_MI2S shared between left and right for stereo
* **Microphone:** Single onboard microphone (MMICT5848) on HS2\_MI2S, configured to left channel by default

**Speaker connection:**

<img src="https://mintcdn.com/qualcomm-prod/Bh7DlgudKfjY_3Wf/Linux/images/peripheral-interfaces/IQ9075_Audio_speakers_connection.png?fit=max&auto=format&n=Bh7DlgudKfjY_3Wf&q=85&s=08b0a52f7ef7efb065e5e375024974cf" width="1078" height="412" data-path="Linux/images/peripheral-interfaces/IQ9075_Audio_speakers_connection.png" />

## Architecture

<img src="https://mintcdn.com/qualcomm-prod/T1k4QQ7G3l_dE-rX/Linux/images/peripheral-interfaces/Audio_architecture.png?fit=max&auto=format&n=T1k4QQ7G3l_dE-rX&q=85&s=d26635d92ec937149c2a715bf6637894" width="1376" height="899" data-path="Linux/images/peripheral-interfaces/Audio_architecture.png" />

| Component       | Description                                                                       |
| --------------- | --------------------------------------------------------------------------------- |
| **PipeWire**    | Multimedia server; replaces PulseAudio; low-latency, flexible media handling      |
| **WirePlumber** | Session/policy manager; handles default sink/source, auto-connect rules           |
| **PAL**         | Platform Abstraction Layer; provides audio-specific APIs and DSP graph operations |
| **AGM**         | Audio Graph Manager; ALSA-based mixer controls and PCM/compressed plug-ins        |
| **ARGS/GSL**    | AudioReach Graph Service; handles initialization and creation of audio graphs     |
| **SPF**         | Signal Processing Framework; modular framework on LPAI DSP                        |

## Configuration Files

| Component                  | Location                  |
| -------------------------- | ------------------------- |
| ALSA card registration     | `/proc/asound/cards`      |
| WirePlumber rules & config | `/usr/share/wireplumber/` |

### Verify Audio Stack

```bash theme={null}
# Confirm ALSA card and devices
cat /proc/asound/cards
aplay -l
arecord -l

# Confirm PipeWire + WirePlumber services
systemctl  status pipewire wireplumber --no-pager

# Validate default sink/source
wpctl status

# Monitor graph
pw-top
pw-cli ls Node
```

## Audio Playback and Capture

### PipeWire Playback

<Steps>
  <Step title="Push audio file to device">
    ```bash theme={null}
    scp test.wav root@<ip-addr>:/opt/
    ```
  </Step>

  <Step title="Set default sink and volume">
    ```bash theme={null}
    wpctl status   # Find sink node marked with *
    wpctl set-default <sink-node>   # If not already set
    wpctl set-volume @DEFAULT_AUDIO_SINK@ 1.0
    ```
  </Step>

  <Step title="Play audio">
    ```bash theme={null}
    pw-play /opt/test.wav -v
    ```

    The command shell should resemble the following:

    <img src="https://mintcdn.com/qualcomm-prod/Bh7DlgudKfjY_3Wf/Linux/images/peripheral-interfaces/pipewire_playback.png?fit=max&auto=format&n=Bh7DlgudKfjY_3Wf&q=85&s=ba11900ed8e51cd65d1490fb85efa6aa" width="566" height="332" data-path="Linux/images/peripheral-interfaces/pipewire_playback.png" />

    Press `Ctrl+C` to stop.
  </Step>
</Steps>

### PipeWire Record

<Steps>
  <Step title="Set default source and volume">
    ```bash theme={null}
    wpctl status   # Find mic node marked with *
    wpctl set-default <mic-node>   # If not already set
    wpctl set-volume @DEFAULT_AUDIO_SOURCE@ 1.0
    ```
  </Step>

  <Step title="Start recording">
    ```bash theme={null}
    pw-record /opt/record.wav -v
    ```

    The command shell should resemble the following:

    <img src="https://mintcdn.com/qualcomm-prod/Bh7DlgudKfjY_3Wf/Linux/images/peripheral-interfaces/pipewire_record.png?fit=max&auto=format&n=Bh7DlgudKfjY_3Wf&q=85&s=e2c51a157a8f92060ee4a5aec7e0d874" width="566" height="229" data-path="Linux/images/peripheral-interfaces/pipewire_record.png" />

    Press `Ctrl+C` to stop.
  </Step>
</Steps>

<Note>
  A value of `1.0` represents 100% volume.
</Note>

### GStreamer Audio

<Tabs>
  <Tab title="Capture">
    ```bash theme={null}
    # PCM capture
    gst-launch-1.0 -v pulsesrc volume=10 ! audioconvert ! wavenc ! \
      filesink location=/opt/audio.wav

    # FLAC capture
    gst-launch-1.0 -v pulsesrc volume=10 ! audioconvert ! flacenc ! \
      filesink location=/opt/audio.flac
    ```
  </Tab>

  <Tab title="Playback">
    ```bash theme={null}
    # WAV playback
    gst-launch-1.0 -e filesrc location=/opt/audio.wav ! \
      wavparse ! audioconvert ! pulsesink volume=10

    # MP3 playback
    gst-launch-1.0 -e filesrc location=/opt/audio.mp3 ! \
      mpegaudioparse ! mpg123audiodec ! pulsesink volume=10

    # FLAC playback
    gst-launch-1.0 -e filesrc location=/opt/audio.flac ! \
      flacparse ! flacdec ! pulsesink volume=10
    ```
  </Tab>
</Tabs>

## Log Capture

```bash theme={null}
# PipeWire logs
journalctl -u pipewire
journalctl  -u wireplumber

# Live debugging
journalctl -u pipewire -f

# Kernel audio driver logs
sudo dmesg
```

## Troubleshooting

<AccordionGroup>
  <Accordion title="No Audio Output During Playback">
    ```bash theme={null}
    wpctl status
    wpctl set-volume @DEFAULT_AUDIO_SINK@ 1.0
    systemctl restart pipewire pipewire-pulse wireplumber



    pw-play /opt/test.wav -v


    # Check services
    systemctl status pipewire pipewire-pulse wireplumber
    ```
  </Accordion>

  <Accordion title="Audio Playback Stuttering or Crackling">
    ```bash theme={null}
    # Check CPU load
    top

    # Check PAL media config (expect rate=48000, ch=2, fmt=2)
    grep "setDeviceMediaConfig" /var/log/syslog

    # Check for underruns
    dmesg | grep -i -e underrun -e xrun -e lpass -e audio

    # Check PipeWire quantum
    pw-metadata -n settings

    # Monitor real-time
    pw-top
    ```

    **Fix — increase PipeWire buffer:**

    ```bash theme={null}
    mkdir -p ~/.config/pipewire/pipewire.conf.d
    cat > ~/.config/pipewire/pipewire.conf.d/99-custom-buffer.conf << 'EOF'
    context.properties = {
        default.clock.quantum = 1024
        default.clock.min-quantum = 1024
    }
    EOF
    systemctl restart pipewire wireplumber
    ```

    **Fix — convert audio to 48 kHz 16-bit stereo:**

    ```bash theme={null}
    ffmpeg -i input.wav -ar 48000 -ac 2 -sample_fmt s16 output.wav
    ```
  </Accordion>

  <Accordion title="PipeWire Service Not Starting">
    ```bash theme={null}
    systemctl status pipewire pipewire-pulse wireplumber
    journalctl -u pipewire -u wireplumber -b

    # Reset configuration
    rm -rf ~/.config/pipewire ~/.config/wireplumber
    systemctl  daemon-reload
    systemctl  restart pipewire pipewire-pulse wireplumber

    # Reinstall if needed
    sudo apt install --reinstall pipewire wireplumber pipewire-pulse
    ```
  </Accordion>
</AccordionGroup>

## Advanced Features

### Echo Cancellation (ECNS) for VoIP

```bash theme={null}
# VoIP record
pw-record /opt//record_voip.wav -v --target=voip-tx0

# VoIP playback
pw-play /opt/record_voip.wav -v --target=voip-rx0
```

Features: adaptive echo cancellation, stationary and non-stationary noise suppression, acoustic echo path cancellation.

## Resources

* [PipeWire Documentation](https://docs.pipewire.org/)
* [AudioReach GitHub](https://github.com/audioreach)
* [AudioReach Documentation](https://audioreach.github.io/)