Hiss / White / Static noise cancellation on Linux using Pulseaudio and Sox

noise-cancellation.sh

#!/bin/bash

# You'll need to have sox, pavucontrol and alsa-utils installed, and the snd_aloop kernel module loaded. 
# You can configure your system to load it on startup or load it manually with "sudo modprobe snd_aloop"

# Once this is script is running, you need to start recording audio in the application of your
# preference, open pavucontrol, go to the recording tab and change the recording source of that application 
# to "Monitor of Loopback ..."

time=5
workDir='/tmp'
sampleRate=44100

# get pulse audio devices
devices=`pactl list | grep -E -A2 '(Source|Sink) #' | grep 'Name: ' | grep -v monitor | cut -d" " -f2`
if [ `echo "$devices" | grep -c aloop` -lt 1 ]; then
    echo "No loopback device created. Run 'sudo modprobe snd_aloop' first."
    exit
fi
 
input=`echo "$devices" | grep input.*pci`
output=`echo "$devices" | grep output.*aloop`

record()
{
    echo "Recording background noise. Keep quiet for $time seconds."
    sleep 3
    pacat -r -d $input --latency=1msec | sox -b 16 -c 2 -e signed -t raw -r $sampleRate - -b 16 -c 2 -e signed -r $sampleRate -t wav noise.wav &
    PID=$!
    sleep $time
    kill $PID
    aplay noise.wav
}
  
cd $workDir

if [ ! -f "noise.prof" ] || [ "$1" == "--record" ]; then
    # record noise sample and create noise profile
    record
    sox noise.wav -n noiseprof noise.prof
fi

GREEN='\033[0;32m'
WHITE='\033[1;37m'
NC='\033[0m'

echo -e "

${GREEN}Redirecting the filtered output to $output...${NC}

    Start recording in the app of your preference, open pavucontrol, go to the recording tab and change the recoding source to \"Monitor of Loopback ...\".
    ${WHITE}You'll need to repeat this process for every application (chrome, skype, etc...)${NC}. But this is a persistent configuration, only need to be done once.
    
"
pacat -r -d $input --latency=1msec | sox -v 0.8 -b 16 -c 2 -e signed -t raw -r $sampleRate - -C 0.5 -b 16 -c 2 -e signed -r $sampleRate -t raw - noisered noise.prof 0.21 | pacat -p -d $output --latency=1msec