I do not mean to disagree, maybe we are seeing this differently...
I multiply compliance numbers given at 100Hz by 1.5, as suggested by resfreq.com. That may be the difference in the numbers we each see. That factor could be higher up to 2.0.
Take Opus-1 for example:
8×10-6Cm/Dyne at 100Hz X 1.5 yields dynamic compliance of 12
12.5g weight + 0.5 gram for bolts is 13g.
At Vinyl Engine, for 18g Effective Mass, compliance of 12 for 13g gives 9Hz, well within their 8-11Hz green range. But even your 10.189Hz would be in that range.
At resfreq.com:
Tonearm EF 18 + Cart+Bolts 12.5 (30.5) yields 8.319Hz.
Atlas at 12 x 10-6cm/dyne at 100Hz X 1.5 gives 18 compliance
11.6g weight + .5g bolts is 12.1g.
VE shows 7Hz dynamic compliance - probably okay ?
At resfreq.com
Toneam EF 18 + Cart+Bolts 12.1 (30.1) with 18cu gives 6.838Hz
Thanks for your MS effective mass, 10-16g.. If it was me I would have distributor tell vdH I'd like adjustment to support 18g EF - which is what I had to do. But the process is very tedious and vdH does as the does.
Yes, you are right, I thought the numbers were given in 10hz and not 100hz.
I actually have written a letter and enclose it with the cartridge going to VdH and also told my dealer what has to be done. What I wanted was the cartridge tuned to my 18gr 4 point. I was told whatever I asked for is done.
Maybe I am missing something but what else can be the reason for mistracking/distortion. I have quadruple checked the alignment, vtf and tried various antiskate and vta settings. I am not talking about treble being forward or sibilance, I am talking about distortion like a white noise/swoosh kind of thing on loud hi hats, or similar sounds that goes on in the treble region and are loud.