For best sound quality, use HDD play music. CD rom player is much inferior to HDD due to:
1. Reading errors
2. Mechanical vibrations.
You need to have a "Perfect CR rom " to match the quality of HDD.
In addition, if you are concerned about sound quality or rate sound quality as an important factor, don't use MP3. Please record those CD using WAV files copy. Use good ripping software such as EAC.