Arp:
More info is needed. Does this happens at the same SPL?
A system component listing can provide a better base to comment on.
Does it happen when there is also bass present in the music played?
Your phrase "It sounds clear below a certain level with no hint of distortion" makes me think it is not inherent to the CD source.
Does the same happens while playing other sources like radio from your tuner (if any)?
What is the volume setting in your preamp when this happens?
More info is needed. Does this happens at the same SPL?
A system component listing can provide a better base to comment on.
Does it happen when there is also bass present in the music played?
Your phrase "It sounds clear below a certain level with no hint of distortion" makes me think it is not inherent to the CD source.
Does the same happens while playing other sources like radio from your tuner (if any)?
What is the volume setting in your preamp when this happens?