Music Editing Software Suggestion

I hope this is the proper place to be posting. I am a big fan of Live music (recording's of concerts), and have quite a few that are 55 minute 1-track albums. I was wondering if anyone knew a software that enables the user to break up a song into 3-5 minute segments, ideally, (nearly) keeping the same sound quality. Most of my files are in .mp3 or .mp4a format.

Thanks in advance!