need to clean up audio noise using sox

Question

What I am doing right now is recording audio from my mic using arecord and piping the raw output to VLC like so:

arecord -r 8000 - | vlc -vvv - 

It works great, except the audio that is coming out has a lot of noise. I know it is possible to clean up background noise using sox, but I can't seem to figure out the right commands. When I use "play" just to test output (without even attempting noise removal), the output sounds horrible using:

play -t raw -b 16 -c 1 -e signed -r 8000 -

Are there any other solutions other than sox/play? If I can do this via VLC itself, that would be ideal. I also need to amplify the sound as well, which is why I use VLC. If I can get sox to clean up the audio and the pipe the output back to VLC again, that would be amazing. How could I accomplish this, I am sure it's possible.

My goals are to (1) clean all the background noise and (2) amplify the audio as much as possible.

Answer 1

Here is a bash script to fix up vocal audio with sox:

#!/bin/sh

# This script shows using several
# effects in combination to normalise and trim voice recordings that
# may have been recorded using different microphones, with differing
# background noise etc.

SOX=/usr/bin/sox

if [ $# -lt 2 ]; then
  echo "Usage: $0 infile outfile"
  exit 1
fi

$SOX "/tmp/tmp_audio_leveled.wav" -n trim 0 0.5  noiseprof newprofile
$SOX "/tmp/tmp_audio_leveled.wav" "$2" noisered newprofile

$SOX "$1" "/tmp/tmp_audio_leveled.wav" \
    remix - \
    highpass 100 \
    norm \
    compand 0.05,0.2 6:-54,-90,-36,-36,-24,-24,0,-12 0 -90 0.1 \
    vad -T 0.6 -p 0.2 -t 5 \
    fade 0.1 \
    reverse \
    vad -T 0.6 -p 0.2 -t 5 \
    fade 0.1 \
    reverse \
    norm -0.5