After having been to the dark side this weekend and spending my first real time listening to mp3 files some may find my comments surprising. I have enjoyed my time listening to them and some of the Compaxx files from streams.
I have been using from NCH Swift Sound their Switch file conversion program after trying others that I have had here with my other recording software and found Switch to sound excellent to me. I have heard differences in truncation programs going from High Bit Rate files back to Red Book and would agree with JA's assessment that doing synchronous conversion does sound best...to me. I really like going from 88.2 to RedBook.
I have found excellent RedBook files I have compared to the MP3 reduced file and find the differences in reduced air, detail, and 3D(if you will) very similar to the differences we all hear in different speakers, amps, CD players, and even ADCs and DACs.
If any of you know of a great sounding file conversion program I would love to hear of it. For now NCH Swift Sound Switch is it for me. Switch is a $20 download.
I will also say the Mini Disc recordings for comparison seem to loose another level of detail, but if all I had to listen to was that I could live with it. Knowing that DSD is out there makes it harder, but when you reconsider the file size...yes, size DOES matter here. I will not take that any further.
I am currently going over some new Compaxx files Tuvia sent me and am trying to discern their differences and come up with some discriptive info that can be of some help to him. Just as Dolby helped the cassette reach hifi status and then the improvement with Dolby C and S, and for the recording industry Dolby A, anything that can help the enjoyment of musis I am for. If it isn't, then I will say so and put my 1 1/2 cent in. I have plenty of music here at the house in LP and CD format that does not sound as good as the excellent RedBook files that I converted to MP3 for this audition. Even my wife agreed and she has no axe to grind about this. She thinks we take this audio stuff to the extreme anyway, but it does keep me out of bars and chasing wild women.
Once you start processing audio files care must be taken as it is easy at reduced file and digital content size to add a "graininess" to the sound that on cheap computer speakers can make the sound almost unbearable. I will tell you that in reality if I play back the MP3 file on my Jolida JD 100 Cd player and the RedBook in my cheaper Sony 755 CD/DVD/SACD player and switching back and forth the MP3 shortcomings sound less so.
There is no doubt to me that any digital file on a lousy system will be just that, and it is the level of gear that members of this forum own and use that can make any file tpye sound as good as it can. I would bet that any MP3 file, converted well, would sound pretty magical on JA's He-Man Rig system and would even trump mine system playing back the RedBook verion.