Download and install Audacity. Open the program.
Drag the MP3 file that you want to convert to the Audacity window. This will automatically copy the file over to the program so you can edit it.
Click the main Audacity menu. Select "Preferences" in the drop-down menu. A new dialog box will appear called "Audacity Preferences."
Click the "Quality" option. You will see a list of options to choose from. In the "Default Sample Format," change to 8-bit. Press "OK."
Select "File." Click "Menu" in the drop-down box locate. Name your file. Click "Save." This will save your file in the new audio format.