I have found that BIAB is not very good at converting to MP3.
In my opinion Audacity (which is free) does a better job and offers some simple quick edit features you can do to your .WAV file just prior to converting to MP3. Ex; Amplify, Compressor, edit length of start and end, fade out, etc...
http://www.audacityteam.org/download/This might seam like a long process but so is tying your shoes if you were to write out each step. Once you get it you will do it without thinking.
You can Download and install Audacity.
Once Audacity is open-
* Edit
*Preferences
*Libraries
*Download LAME MP3 Library
That should take you to: How do I download and install the LAME MP3 encoder? on Audacity's website.
Follow those simple instructions.
After that is done I think you will need to close and re-open Audacity and the first time you attempt to convert to MP3 it may find the LAME codec or may ask you if you want to locate it. If so, you would go back to Libraries and use the LOCATE box.
Use BIAB to save your song to .WAV.
Open Audacity.
File
Import
Audio
Navigate to your .WAV file
Open
It should load into Audacity.
Practice a Export Audio process to make sure you get it correct. You can change the name with a 1, 2, 3 at the end so you know when you got it figured out when you can play back the file in your media player
Now you can open your original .WAV file in Audacity again and use some of the Effects and the Tools all the way on the left side. Namely Selection Tool and Zoom Tool. Also handy is Delete - Undo and Edit - Remove Special - Silence Audio.
Hope this helps.
I also have Reaper DAW that works great and a dedicated DbPowerAmp Music Converter. But I mostly use Audacity for converting songs I created in BIAB and RB.