ffmpeg.exe -i "input.mp4" -vn -t 2:05 -q:a 2 "output.mp3"

-vn removes the video stream,
-t cuts to whichever time you wish, here set to 2min and 5s,
-q:a scales the quality bitrate (I previously had it at 128 kbit/s, with -q:a 2 it resulted into 148.6 kbit/s)

-ss would be to start at said time,

If you're using Windows, you can download ffmpeg here https://ffmpeg.zeranoe.com/builds/ , ffmepg.exe is available in the bin/ directory.

Thank to my dear friend Ramiro, the lord and master of ffmpeg for his greatful help.

EDIT: Glue/concatenate/put together several files together:

ffmpeg -i "concat:input1.mp3|input2.mp3|input3.mp3" -c copy output.mp3
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