Improving audio playback quality
From MEPIS Documentation Wiki
To maintain a greater level of compatibility with sound cards, the Mepis Live-CD uses an 8-bit sampling rate, but most sound cards since 1997 have been capable of 16-bit sampling or sometimes even higher.
You can change the sampling rate of your sound card from 8-bit to 16-bit and dramatically improve the audio quality of almost everything you play through Mepis very easily.
Open Konqueror File Manager (or your home folder) and type "settings:/Sound/" without the quotes into the address bar and press return.
To change the audio sampling rate, click on "Sound System", then the Hardware tab, then change the audio quality from "8 Bits (low)" to "16 Bits (high)", click the apply button and your sound system will be restarted with the 16-Bit settings.
To hear the difference between 8 and 16-bit, before you make the change, instead of clicking on "Sound System", click on "System Notifications" choose "KDE is starting up" in the top half of the window, then under Actions, click the play button to play the selected sound file and listen carefully to the audio output, listening for background hissing and overall clarity. Repeat this step after making the change and compare the difference, you should hear a much nicer sound.