"Splashy" treble to me is a combination of things. Lacking of detail, focus, attack & decay, harmonic overtones, air and the seperation of notes, etc... It can be "close to sibilant" in many cases.
As an example, a cymbal that is cleanly and quickly struck with the tip of a drum stick near the center will produce a very definite rise and fall of sound with natural bell-like overtones. You can pick out the harmonics as the note quickly rises and then slowly shimmers into decay. Think of a good jazz drummer and you'll know the sound that i'm talking about.
On the other hand, a cymbal that is struck with the "meat" or "side" of the stick by a "ham fisted rock drummer" will sound much flatter, lack any specific tonality or overtones and will not have near as pronounced beginning or end. I.E. it is "smeared", "splashy" or "blurred" since it lacks detail, definition, harmonic structure, etc... It is more of a "crash & splash" smearing of notes rather than a "strike & shimmering decay" of notes. Know what i mean ???
As to the bass on Chris' 27 pair CAT 5 design, it has the greatest amount of bottom end and overall "weight" that i have experienced from a cable of that type. If you had speakers that could be biwired and sounded slightly lean and lacked extension, using this cable for the woofers could easily fill things out. If i remember correctly, it is equivalent to about a 10 gauge i.e. Goertz MI-2 or Kimber 8TC but with WAY more "oomph" in the bottom octave. Sean