Depends upon your mp3 softw! Some can add bass & fx for playback but this is not necessarily saved when burning to a cd if that's your intention. Again, it depends on your particular softw. If it's a full audio cd yu want to end up with. Use an audio editor to add fx that u desire. A very good one that's free is Audacity (click on link) & yes u can add bass fx & also use vst plug-ins if u have any. Audacity can open, save & convert between mp3's & wav/aiff & there's a version for windows & another for mac. Hope this helps.