User blog comment:Forwhomwelove/NicoSound/@comment-4565782-20140206052107/@comment-25986720-20150207121322

I dont think ACC is better then mp3 at all. acc format is seen mostly in a video information (as audio channel of one video) but rarely be a single file. mp3 still be the best choice for lossy audio format if u wanna just to hear in any player or in ur smartphone (i do not count apple things with their m4a type which surely is not as good as mp3).

The best way to take sounds from NND is: download the video, use converter to rip the audio offline. setting for the export file of almost online converters quite such :/!