Compared to the WAV and AIFF files (35.3MB), the 320kbps MP3 file throws away more than three-quarters of the audio, and the 128kbps file reduces the audio file to less than 10% of its original, uncompressed size. It''s actually astonishing that MP3s don''t sound worse than they do.
I''m not happy with the mastering on a CD I recorded a few years ago, so I approached a mastering engineer about remastering it. I ripped a 320kbps MP3 from the CD for him to remaster, but he said he preferred to work with WAV files, and asked me to provide him with one. Couldn''t a pro mastering engineer convert an MP3 to WAV himself? Do you think this guy isn''t legit?
Wow . . . there are so many things wrong here, it''s hard to know where to start.
The reason why the engineer asked for a WAV file is because when songs are mixed, they''re usually mixed down to a WAV or AIFF file. Then, if the artist wants an MP3 copy, that mixed file is converted to MP3. However, the conversion process compromises quality compared to the original file. Being able to work with the original means the engineer can master the highest-quality version of the song, and give you the highest-quality master as a result. (Remember the old computer-related maxim, “garbage in, garbage out.”)
But in this case, that''s the least of your problems because you were providing a song that had already been mastered, and in your opinion, badly. This is kind of like giving a chef a steak that''s so well-done it''s burned to a crisp, and asking him to please make it medium rare. That nasty mastering is baked into the cut, and expecting a mastering engineer to be able to undo it is asking a lot. Maybe there can be a slight improvement, but don''t expect much.
Also, there''s a misconception among some people that converting an MP3 file to the WAV or AIFF format will restore the quality lost during the MP3 conversion process. MP3 files supposedly use a “data compression” algorithm, but it''s really a “data omission” algorithm that throws away part of the audio it deems unnecessary. (That''s why the file size is smaller.) Once that audio is deleted, you can never get it back. So while you can convert MP3 to WAV, all you''ll have is a faithful reproduction of the MP3 format file—not the same level of quality as the original.
Find a copy of the original mix, without any added dynamics or EQ processing, and you''ll have a happy mastering engineer—and you''ll be a happier client.