If I’ve already downloaded my audacity audiobook files to mp3 but for some reason they are not correct CBR can I go back into mp3 file to edit the format for compatibility of 192 kbps?
You didn’t save the uncompressed original?
Yes you can can re-compress to a higher bitrate but the quality will get worse, even at a higher bitrate-quality setting. It might still be acceptable but it’s “cheating” and you should avoid doing this if possible.
can I go back into mp3 file to edit the format for compatibility of 192 kbps?
No. That’s one of the disadvantages of MP3. Once you make a bad one, that’s the end of the world. It always gets worse from then on.
Open each of your perfect quality WAV Edit Master chapters and burn a new MP3.
Did you miss the Constant Bit Rate setting? I think Audacity defaults to Variable Bit Rate now. Or did you pick the wrong actual rate number? ACX has a special 128 super high quality bit rate number because they are going to do production and processing later before offering the book to the public.
Did you make your Chapter Edit Masters as WAVs or Audacity Projects? That’s highly recommended. Doing production directly in MP3 is dangerous.