I have been contemplating this very topic,because I have noticed my turntable front-end, both acquiring and losing these very qualities with some aspects of fine-tuning and set-up.
My turntable is the Yamaha GT 2000,the cartridge is the Soundsmith 'The Voice(ebony)',the phono stage is the Simaudio Moon LP 5.3.
My June 2011 purchase of the Audeze LCD-2(rev2) headphones and Violectric HPA V200 headphone amp,have provided me with a first class expose of my front-end.I have been utilising the combination's qualities of musical naturalness and musical insight to fine tune some aspects of my turntable set-up.
One of the repeated effects I have become aware of,is the importance of bearing spindle perpendicularity.In other words; Does your spindle lean in any way or is it 'plumb'?
I repeatedly notice that my turntable sounds better when I take the time to ensure that the platter is leveled.I speculate that if the bearing spindle is rubbing against the bearing sleeve,noise is generated which is not detectable to the ear,as noise,but subjectively is noticeable as a loss of 'musical' integrity.
Another aspect of my turntable fine-tuning that effects the same musical quality is the isolation of the turntable.I use 14 Clearaudio Magix underneath my turntable.These mag-lev footers are incredibly difficult to optimise.They are no respecters of components whose Center of Gravity is not also the the dimensional center.Thus there is the problem that some of the Magix are more compressed than the others.I speculate that this results in each of the footers isolating at a different frequency,which could not be the ideal effect.Compound this with the observation that the Magix sound different depending upon how much they are loaded down,and you have a irritatingly difficult task of optimising those three aspects(equal loading on each footer,along with finding the optimal load of the totality that they support,whilst maintaining perpendicularity of the spindle).
I'm explaining this in a round about way,because my observations are that each of these parameters,has an effect upon the sound quality.The most noticeable to my ears is the quality of syncopation and emotional connection to the music.The other hi-fi aspects of the sound(bass,dynamics,detail) suffer and improve also,as one either moves closer to,or moves away from optimising the three parameters I mentioned above.
This was an unexpected finding for me,though I had noticed effects along these lines when attempting to optimise another mag-lev platform(the SAP Relaxa 3+).
These are my observations only,and by no means an attempt to put forward a scientific explanation.I offer them here,only because the observations surprised me and they are relevant to the topic under discussion.
Take my observations with a grain of salt if you wish.I have no desire to be quoted or regarded as an an audio-maven.