neutral and warmth are mot the same. thus, if a stereo system is considered "neutral" it is not considered "warm". if a stereo system is considered "warm" it is not considered "neutral". thus if neutral is a term denoting no coloration and warm is not neutral, it follows that warm is a coloration.
warm is used to indicate an emphasis upon a certain aspect of frequency response. if a cd is warm it doesn't mean the stereo system is warm. not all cds are warm, so that if the stereo system is warm all the times, it is a coloration.
if one cd is warm and another is not , the one that is not will probably sound more resolving of musical information.