K3b supports ripping an audio CD via FLAC.
FLAC is an audio format, data is compressed with no loss of information or quality.
FLAC is a format option for archiving audio collections such as CDs.
Ripping a CD to FLAC allows an exact copy of an audio CD to be created if the original is lost or damaged.
Select: File > New Project > New Audio CD Project > CD > Start Ripping > Settings > Filetype > FLAC (located in drop down menu) > Start Ripping
The FLAC package may need to be installed if it is not available in the drop down menu, check the software repository of your distribution.