My CD player is unique in that it has 2 analog filters to choose from. One the manual describes as having a very linear frequency response. This one makes the instruments sound like everything is shoulder to shoulder in a line across the sound stage. This is a similar trait my Krell players had. The benefit to this is sometimes subtle details are easier to hear because of the evenness, another, a more controlled bass sound. The second one has a less linear frequency response and I forget exactly how they describe it in the manual. When switching to this your hear the sound stage almost relax, a depth is perceived, instruments have more of a 3D image and more ambient information. I personally like the 2nd better. I'm sure not everyone after listening to the two would agree but it got me wondering if this difference could all be just frequency response and as we all talk about difference in gear, or lack there of, I really find it interesting that this type of difference can be made with just a filter. To me, this shows one account of how difference, can, be made. If you had two players of the same quality using the typical one filter application, brand A uses a linear filter, brand B uses one not so linear, then how can you deny a difference in sound? The two players may even look virtually identical on paper.

Thinking of synergy, how would a linear CDP effect a system not so linear? There could be varying preferences but I think most would find that synergy would happen best when a player has the same character as the system it's placed in.

Anyway I have been fascinated by this filter thing and thought I'd throw it out to inform and insight