Bolero:why can't my system reproduce snare well?

You need to provide more information for suggestions to be relevant. Have you ever heard "Bolero" live? Are you aware that the snare is supposed to be played as softly as possible and slowly gets louder only as other instruments join in? Often, the snare is situated at the rear of the orchestra so it will, in fact, sound "distant"; even later in the piece when the orchestra is playing fff. Now, you feel that it also sounds "muffled". Do the string pizzicato (plucked) notes have the appropriate snap? Do the upper winds and brass have the appropriate brilliance? If they do, then it's unlikely that the problem is your system. You may be expecting the kind of snare sound that is often heard in pop or jazz recordings where a mic is placed very close to the snare. Most well recorded classical recordings will not provide that kind of sound.

Lowrider makes very good points about the role of the conductor and producer in determining the sound of the orchestra and solo instruments (in the case of a piece like Bolero). Sometimes the end result of a producer's "artistic license" can be a good thing; other times, as in the Dudamel/Vienna Youtube clip, not so good. Yes, the snare is very well defined in that clip, but it is unlike anything one is likely to hear at a performance. The balance between the snare and opening flute solo is totally wrong. The players may be playing a true pianissimo but it doesn't sound that way due to the miking. It is true, as Lowrider points out, that most modern recordings of the piece will be close(r) miked; an unfortunate reality from the standpoint of faithfulness to the score, even if sometimes sounding "better defined". Not even sitting on stage will one hear a snare sound that way when the player is playing a true pianissimo.

In this other performance, notice what the snare drum player has done which is fairly common: he has placed a small towel on the drumhead in order to further mute the sound (he also is situated further upfront within the orchestra); it is possible that is what the OP is hearing as "muffled". This is closer to what one is likely to hear sitting in the audience at a live performance:

http://m.youtube.com/watch?v=A2BYkJS8GE0

Great article, Al; interesting read and thanks for sharing. Would be interesting to see similar graphs showing the effect on high frequency content relative to low frequency content at different distances from the microphone. On a lighter note:

http://m.imgur.com/r/classicalmusic/9cuc2

Elegal, as Mapman says, then you have a good point of reference. Please tell us what recording of Bolero you are listening to; that may be very instructive.

Allowing for the possibility that Elegal is particularly sensitive to and keyed into the sound of the snare, I fail to see how changing the interconnect cable so that the sound he is hearing from the snare ("terrible/muffled") can be transformed to acceptable without creating a slew of problems for the sound of other instruments; IOW, other instruments sounding in the frequency range of the snare which sounded acceptable previously would then be too bright and forward. Power cords and vibration control would clearly be a help across the board; but still....... That is the problem with focusing on the sound of one instrument (or one type of music for that matter) when choosing equipment or tweaking a system, and leads to the typical audiophile chase which "solves" one problem and creates others. Until the OP reports back on how other recordings of Bolero sounded on his system, my money is still on unrealistic expectations for the sound of an ORCHESTRAL snare as the problem.

****Obviously these are not snare-specific suggestions, (and are presented with the usual disclaimers: Imo, ime, ymmv, etc.)****

Exactly; and it remains the key question still unanswered by the OP: why is it only the snare that seems to be affected? How do other instruments sound? More info would be very useful for helping to solve the problem.