Quellformat beibehalten - nach Speichervorgang

Well, it's MP3 you are talking about and Audition doesn't handle those directly anyway - they have to be decoded. What this means is that your original MP3 remains intact, regardless. Your options at that point are to save the file as opened - which is inherently a wav file, because that's Audition's internal format, or to use Save As, which will let you encode it to any format you like. The important thing to note is that every time you save an MP3 file that you've opened as another MP3 it will degrade, because it's a lossy format - it's the re-encoding that causes the problem, and that's inevitable.

Ultimately what it comes down to is that MP3 files were originally only really intended to be distribution files, and not meant to be worked on, as such. using them for any other purpose involving editing will always have this issue, regardless of what you edit them on. There are a couple of editors that will work directly on MP3 files in their encoded state, but the range of operations is limited to straight cuts, and small changes in the file level - anything else requires a decode.