unity exports mp3 2x larger than mp3 original size.

I found a terrible problem. For example my mp3 file in assets is 3MB and 128kbps. I set the same Unity export compression parameter 128 kbps, no 3D and get 6MB size(!) I use Audacity and lame encoder. Is it possible to fix my problem? It is importent for my Android app.

 

If the Audacity Project is entirely mono, then the exported MP3 will automatically be mono without you needing to do anything. search for import settings in unity.... ogg is better anyway, smaller and more options in unity.http://stackoverflow.com/questions/8859321/smallest-audio-file-mp3-ogg-or-wav