surely if DACs on CD players did some sound shaping they'd all have to do the same thing, otherwise CDs would sound different from player to player.

As I understand it, that's exactly the case: CDs do sound different from player to player because of different DAC implementations.

From a logic POV, it just doesn't make sense for the DACs to do any shaping themselves.

Well, actually, the DACs have to shape the sound to a certain extent. A 16-bit 44.1khz wave sample is just an approximation of a real wave. How the DACs fill in the "gaps" between the sample points is at the root of the question.

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Tony Fabris