Cartridge Loading and Compliance Laws

All this together would seem to indicate that the stated VDH 35 Micron/mN compliance is the same as saying 35 x 10-6 cm/dyn only in different terms. If testing was done @ 100Hz. I think...

Its kinda like saying .5" is the same as 1/2" Right?

My math could be flawed though, so if that is the case anyone please feel free to correct these statements above.

There is no formula to convert static compliance to dynamic. In fact dynamic cu can be different laterally than vertically. For resonance estimates vertical is normally used. Most specs are dynamic cu. For example, most Benz carts are 15cu (dynamic). VDH only gives static, but tells you eff mass range of arms for the cartridge.

The only examples of both static and dynamic I could find listed is AT. The 33EV has a static cu of 40. Dynamic is 10 @100Hz. That's equivalent to approx 17, 18 @10Hz. There is no reliable formula to convert 100Hz to 10Hz.
www.lpgear.com/product/AT33EV.html

IMO it's better to find out what makes a good match from other users. Resonance estimates are often wrong and great sounding combos can be outside of the recommended range. If you want to find out exactly what res freq is, get a test record. You're more likely to get bad results with a low cu cart on a light arm. When res is near the audible band it can impact on the music.
Regards,

Not that I disagree because to be honest I am not absolutely certain but maybe someone can check with a mfg. like VDH or Lyra about that conversion. There are others who believe those numbers can be compared with accuracy.

What on earth would make someone like VDH put a number like that for compliance spec if nobady can understand it?

I hear you though, maybe trial and error means everything but not all of us have the luxury of rolling dozens of arms and carts just to find out which ones work well together. Thats why specs are important to me imo so that I can try to put something together which I think might be close to being right combo the first time. Maybe thats why some people get sick and frustrated of analog before they get a taste of what it can really do. just my 2 cents here and thanks for the knowledgeable people (like Fleib) kind enough to provide their input.

Jeremy,
I think what Fleib is saying is to read what others post here as workable combinations.
This will save you the task of testing dozens of cartridges yourself.
What Fleib is also saying (and I agree wholeheartedly).....is that there is enough doubt and inaccuracies in theory and printed data as to render them dubious in accurately providing correct indications?

Jeremy,
Halcro said it more succinctly than I. That's what I mean. Resonance calculators are just an estimate. I've calculated combinations that should resonate at 8Hz, and they tested at 10Hz. Effective mass is will change with things like the distance of the counterweight from the pivot (moment of inertia). Cartridges might vary somewhat or age. If you're really interested in the math I suggest that you go to Vinyl Engine and do a search or ask in the forum.

Re: 100Hz conversion. There doesn't seem to be an exact formula for conversion. Carts in the 10cu range (100Hz) have 10Hz cu approx 1.75 x that. The AT-150MLX, 33EV (10cu @100)have cu = 18 approx. An AT-95 or Clearaudio MM has 6.5cu @100Hz and approx 15cu at 10Hz. The DL-103 has 5cu at 100, and seems much stiffer. An old Pioneer PC-401MC has static cu of 16 and 100Hz dynamic of 12cu. VTF range (1.7 - 2.3) would indicate a stiff suspension. None of this makes much sense for arm matching. 100Hz cu seems more like a measure of tracking ability at 100Hz (bass), than cu around res freq which is near 10Hz. The only correlation I can come up with is a sliding scale. Low 100Hz cu is more than doubled for conversion. Med - 10cu is x 1.75. Higher, around 12 to 16 @100 is closer to to that number.

There are other things to consider as well. Certain combinations will work better, in some cases, than others, even though compliance/mass would seem OK. That's why it's really more effective to ask or read what the best matches are.
Regards,