.Is there anyway, I can compress my 90 minute audio file (I know I will probably lose quality) so that it will fit on the CD?
If you convert to mp3-file, you loose quality.Use FLAC. Then you can get a smaller file, without loosing quality.
Converting the file to mp3 will make the file smaller, but it won't make it any shorter. It will still be 90 minutes, meaning the length is still too long.