linux-voice-assistant/docs/enabling_aec.md

Enabling Acoustic Echo Cancellation

Acoustic Echo Cancellation (AEC) is a type of sound processing used to cancel out the noise coming out of your speaker and going into your mic. In LVA this functionality can be useful to allow LVA to listen to wake words even when audio is playing, particularly when a timer is playing. PulseAudio and PipeWire already provide built-in modules for AEC.

Enabling AEC

PulseAudio

pactl load-module module-echo-cancel source_name=aec_mic aec_method=webrtc

To make permanent, add to /etc/pulse/default.pa:

load-module module-echo-cancel source_name=aec_mic aec_method=webrtc

PipeWire

pw-cli load-module libpipewire-module-echo-cancel '{ aec.method=webrtc source.props={ node.name=aec_mic } }'

To make permanent, add the following to the context.modules section of /etc/pipewire/pipewire.conf:

{ name = libpipewire-module-echo-cancel
    args = {
      aec.method = webrtc
      source.props = { node.name = aec_mic }
    }
}

Or if you are using a standard PipeWire installation without a custom pipewire.conf, create a new file inside pipewire.conf.d/:

context.modules = [
  { name = libpipewire-module-echo-cancel
    args = {
      aec.method = webrtc
      source.props = { node.name = aec_mic }
    }
  }
]

Using the AEC Input

In the .env file:

AUDIO_INPUT_DEVICE="aec_mic"

Changing Source and Sink for AEC

PulseAudio

pactl load-module module-echo-cancel source_name=aec_mic aec_method=webrtc source_master=<mic-source> sink_master=<sink>

PipeWire

pw-cli load-module libpipewire-module-echo-cancel '{ aec.method=webrtc source.props={ node.name=aec_mic node.description="Echo Cancelled Mic" } sink.props={ node.name=aec_sink } capture.props={ node.name=<your-mic-node-name> } playback.props={ node.name=<your-speaker-node-name> } }'

To make permanent, add to context.modules in /etc/pipewire/pipewire.conf or a file in pipewire.conf.d/:

{ name = libpipewire-module-echo-cancel
    args = {
      aec.method = webrtc
      source.props = {
        node.name = aec_mic
        node.description = "Echo Cancelled Mic"
      }
      sink.props = {
        node.name = aec_sink
      }
      capture.props = {
        node.name = <your-mic-node-name>
      }
      playback.props = {
        node.name = <your-speaker-node-name>
      }
    }
}