i have several cd players, and a transport.
the transport is a ps audio perfect wave dac. my favorite cd player is the audionote cd2. ialso own other cd players.
with respect to cd mats, of which i have several, including the previous marigo mat and millenium mat,
both the ps audio and audionote when used with a mat, sontribute to a degradtion of sound.
so inaddition to an improvement in sound, no difference in sound add a cd mat as detrimental to the sound.
while the latter case seems counter intuitive, you'll have to trust me on my perception because there is no evidence to disconfirm it.
of course i'll admit that one person's idea of an improvement may be another's sense of a worsening of sound.
incidentally, in all of the posts where components are compared and assertions are made as to one sounding better than another, the subjective nature, and the connotating criteria, vary among audiophiles.
such is the reason for being careful when making a serious decision based upon sense perception.
when one can return a component, the cost is only shipping.