Hi @dover , yes, no doubt this its true. I have experienced it with tonearms like the Tri-planar VII u2 that have counterweights of different sizes, allowing one to locate the weight near the pivot or farther from it to achieve the same VTF. But what I’ve observed with my Grahams is different.
In the two scenarios--emphasized treble, de-emphasized treble--the position of the counterweight relative to the pivot is identical and the VTF is exactly the same, down to the 1/100th of a gram. The difference is whether the counterweight arrives at that position by screwing or unscrewing the furled knob at the end of the rod. Screwing=emphasized; unscrewing=de-emphasized treble.Weird but true, at least with both my Phantoms. And I want to underscore that the effect is subtle. The arm sounds good in either case, but different, at least to my ears. In fact, once the desired VTF is obtained, I can slightly "lean" on the furled knob--just barely pressure it--to slightly shift the tonal balance without actually changing the VTF, again, down to the 100th of a gram. This is what makes me conclude that the cause is the tension, in one direction or the other, of the threaded rod within the carriage structure, and how it affects the resonance of the bearing housing and overall tonearm.
Once again, subtle stuff. But isn’t analog set-up all about subtle stuff and wrangling resonances? I offer it as a way to get the best out of these excellent arms.