Not bad for boosting 5.1 movie volume, which is never mixed to stereo properly by any media player or television I've used (always have to turn up the volume to even remotely hear the speaking parts, then frantically dig around for the remote once the swell of music or explosions start):
sox -S .\audio.wav audio-amp.wav remix -m 1,3,4,5 2,3,4,6 gain -n


