All I can offer today is frustration. Here's a short article about a highly unsuccessful attempt to enable K3b to burn MP3 files to audio CD on CentOS. There. http://www.dedoimedo.com/computers/centos-7-k3b-mp3-audio-cd.html Cheers, Mrk
I think I didn't have these problems with CentOS 6, as you suggested anyway. Scientific Linux 7 and CentOS 7 seem to be big failures...