A webpage to help document a good mic noise reduction setup. It needs to be adapted to your voice. We want to filter noise as much as possible, while maintaining a clear, loud and pleasant voice for our listeners.

Regardless of the OS that you use, test your results and disable all processing of voice from the application that you use. For example, disable automatic volume adjustments and disable noise reduction from application settings

We want our plugins to do noise and volume processing, because they do it better and with our personalized settings!

Inspired from https://gist.github.com/MateusRodCosta/a10225eb132cdcb97d7c458526f93085 and https://fedoramagazine.org/tune-up-your-sound-with-pulseeffects-microphones/

Pipewire + Carla will be used. Configure pipewire for your distro, test it. Follow distro documentation.

Echo cancellation to prevent echo when using speakers and mic Latency must be a multiple of 480. Increasing latency will prevent Xruns in Carla. Autoconnect to your mic. (Use target.object)

~/.config/pipewire/pipewire.conf.d $ cat 20-echo-cancel.conf

 context.modules = [
  {   name = libpipewire-module-echo-cancel
      args = {
          library.name  = aec/libspa-aec-webrtc
          node.latency = 960/48000
          aec.args = {
            webrtc.noise_suppression = false
            webrtc.high_pass_filter = false
            webrtc.gain_control = false
            webrtc.voice_detection = false
          }
          source.props = {
             node.exclusive = true
             node.name = "Echo Cancellation Source"
             target.object = "alsa_input.pci-0000_00_1b.0.analog-stereo"
             #node.latency = 512/48000
          }
          sink.props = {
             node.name = "Echo Cancellation Sink"
             #node.latency = 512/48000
             # node.autoconnect = false
             # target.object = "upmix51capture"
          }
      }
  }
]

Some conferencing applications do not support jack input, thus we need a dummy duplex device to connect carla and those applications

~/.config/pipewire/pipewire.conf.d $ cat 30-virtualmic.conf
context.modules = [
    {   name = libpipewire-module-loopback
        args = {
            audio.position = [ FL FR ]
            capture.props = {
                media.class = Audio/Sink
                node.name = my_sink
                node.description = "my-sink"
                #node.latency = 1024/48000
                audio.rate = 48000
                audio.channels = 2
                audio.position = [ FL FR ]
                node.autoconnect = false
                #target.object = "my-default-sink"
            }
            playback.props = {
                media.class = Audio/Source
                node.name = my_source
                node.description = "my-source"
                #node.latency = 1024/48000
                audio.rate = 48000
                audio.channels = 2
                audio.position = [ FL FR ]
                node.autoconnect = false
                #target.object = "my-default-source"
            }
        }
    }
]

Restart pipewire.

Start carla like this:

pw-jack -p 960 carla

If Carla's buffer size is not 960, restart carla until it is.

Make engine settings as below and restart Carla

Using qpwgraph, you can connect Carla to echo-cancel source and Sink. Thus, you should hear your voice when you test. I suggest to test your voice with headphones to prevent echo. Test when you say a whole phrase/sentence, not only individual words. Make sure that the mic is not peaking. All plugins in Carla must not touch the red areas in the volume bar of each plugin. If the mic is peaking reduce the sensitivity/capture volume of it, through Alsa or Pulseaudio mixer.

Use masterme graph to adjust the gate and check how loud your voice is made.

After you are happy with the settings of all plugins, store the carla plugin chain in a Carla project file. (For example voice.carxp)

1. Equalizer (lv2 plugin) https://lsp-plug.in/?page=manuals&section=graph_equalizer_x16_stereo
2. Master me (lv2 plugin) https://github.com/trummerschlunk/master_me It acts like gate + compressor + limiter
3. Calf Desser (lv2 plugin) https://calf-studio-gear.org/doc/Deesser.html
4. Noise reduction plugin (vst2 plugin) https://github.com/werman/noise-suppression-for-voice

You can use FFT analysis to see how your voice is heard. Remove very low frequencies and try to make your voice sound less muffled. Maybe decrease central frequencies and increase high ones.

From easy view select 'speech general' preset. Then switch to expert and activate gate. You need to select the threshold of the gate based on what is heard when no or low sound is made. Use 3 ms as attack and 500ms hold and 50ms as release. You can play with hold value if you hear that your voice is chopped. This plugin will insure that your voice is heard loud and clear.

Due to compression you might emit 'sh' or 'ch' sounds that make your voice very unpleasant to listen. Desser can fix that. With the help of equilizer and fft analysis test phrases that have many 'sh'/'ch' sounds for the language that you speak. Use also the listen button to hear what it filters out. (It shouldn't destroy vowels)

This plugin should remove unwanted sounds, like keyboard keys, cars, fans etc. Use the below settings.

After saving the project, you can automate startup like this:

#!/bin/bash

pw-jack -p 960 carla ~/voice.carxp &
sleep 5
pw-link -d alsa_input.pci-0000_00_1b.0.analog-stereo:capture_FL Carla:audio-in1
pw-link -d alsa_input.pci-0000_00_1b.0.analog-stereo:capture_FR Carla:audio-in2
pw-link -d Carla:audio-out2 alsa_output.pci-0000_00_1b.0.analog-surround-51:playback_FR
pw-link -d Carla:audio-out1 alsa_output.pci-0000_00_1b.0.analog-surround-51:playback_FL
pw-link Carla:audio-out2 "my_sink:playback_FR"
pw-link Carla:audio-out1 "my_sink:playback_FL"
pw-link "Echo Cancellation Source:capture_FL" Carla:audio-in1
pw-link "Echo Cancellation Source:capture_FR" Carla:audio-in2

This is how carla and applications look connected

Follow this guide to use equalizer APO:

https://medium.com/@bssankaran/free-and-open-source-software-noise-cancelling-for-working-from-home-edb1b4e9764e

Master Me plugin is also available for Windows. So you can use it before noise reduction. Any suggestion for free VST eq plugin and deesser?