i have always notice a huge difference in the quality from wav files to mp3 files i think it has to do with the lame file…if i want to keep the crisp sound i usually export from audacity in wav format and use a third party converter to conserve quality
MP3 encoding is always lossy (whatever converter you use) and WAV PCM encoding is always lossless (unless going down to a lower sample rate or bit depth than the original file).
LAME is usually regarded as one of the best (if not the best) MP3 encoder.
Note that the default Audacity MP3 export bit rate is 128 kbps. You can click Options… when you export MP3 to choose a higher bit rate (for higher quality and greater file size) or to choose variable bit rate encoding (which varies the bit rate around a target level to maintain the same degree of quality throughout the file).
Topic split and given a relevant title as this post has nothing to do with problem that was being discussed.
Audacity uses Lame to encode MP3 files. Lame is one of the best MP3 encoders available, and the only one that is still actively developed, however the nature of MP3 and other “lossy” formats is that there is a trade-off between sound quality and file size. High compression setting will produce smaller files but with lower sound quality. Lower compression settings will produce larger files (though still very much smaller than WAV files) at higher quality. 128 kbps is the minimum that should be used for reasonable quality stereo music. 256 kbps VBR gives excellent sound quality that is virtually indistinguishable from the original.
If you are getting poor quality MP3 when you export from high quality projects, check the MP3 options. See here for more information: http://manual.audacityteam.org/o/man/file_export_dialog.html