Help me understand compliance!

As one engineer to another we can communicate with each other in technical terms and understand each other.  The great beauty of science. In layman's terms my explanation of the matter has left you with an inability to track my thought process.  We need to increase your compliance to see this philosophically.  :-)  Not everybody as the scientific method at their fingertips.

Korf Audio have an interesting take on it, there ae 4 blog posts and a handy calculator.
http://korfaudio.com/blog67

Using the Ortofon calculations my 18g Schröder with an SPU Royal N should resonate at around 10Hz, on a HFN test record it actually throws a wobble at 7Hz lateral but nothing at 6 or 8Hz vertically, nor at any other frequency for that matter.

As above, use a Rega cartridge with a Rega arm and you won’t go wrong, they’re made for each other.

I just posted by experience on another thread, but it fits here too

When the second of my B&O RX2 turntables gave it up, after a fair amount of research, I ordered a Mofi Studiodeck because I knew I would need complete adjustability to mount the Soundsmith SMMC1 B&O cartridge on another turntable. In that price range, the Studiodeck seemed to fit the bill. Only after the turntable shipped did I learn about potential compliance issues, and that the total 1.5 grams of my Soundsmith high compliance cartridge and adapter were an impending catastrophic mismatch for the heavy arm on the Mofi Studiodeck. Certainly just waiting to happen in some horrible sonic way. I read forum threads I did not understand about resonant frequencies, analogies to car suspensions on trucks, or vice versa, and debates about physics and engineering formulas, without figuring out how the mismatch was supposed to manifest in the sound I would hear.

I closely followed the cartridge alignment instructions on the Soundsmith website, paying particular attention to anti-skate (had to remove some of the weight from the thread) and azimuth, and tinkered with VTA with some albums suggested on these forums so that the highs were not sibilant and base not flabby.  I have yet to hear any ill effects of the guaranteed mismatch. In fact, I would not have believed that a change in turntables could have made such a difference, particularly in surface noise. I am listening to albums I had pretty much given up on.

There might be sonic gremlins that my system is not resolving enough to uncover. If that's the case, fine. Meanwhile, I'll let the Ohm Walsh 4's and REL subs kick some Talking Heads throughout the house.

Steve

@yeti42, good for you. Measuring is the only way to go. There is enough variability in cartridges and tonearms that the predicted resonance frequency can be a good deal different than the measured one as you noticed. You are not seeing the vertical resonance because it is being well dampened. 8 Hz is perfect, what I shoot for. You can see the vertical resonance if you use a more sensitive measurement device like an oscilloscope. You can put a seismometer app on your phone and place it on your speaker or subwoofer and you might be able to see it. I have not tried it yet but I will once I get my system set up again. 

I find the Korf Audio blog post linked above to be very interesting and am surprised nobody makes note of the fact that he seems to call out the "way everyone does it" as flawed.  I have tried to back out the actual compliance from other know parameters and found like korf that something else dominates this equation.  Below are his conclusions from post IV

http://korfaudio.com/blog70http://

1 Carlson's formula of a low frequency resonance does not describe the measured low frequency behaviour of the cartridge/tonearm interaction

2 Modern cartridges (meaning all those built in the last 60 years or so) have too much suspension damping and non-linearity for the resonances to dominate

3 The frequency of the observed motion is determined largely by the frequency of the excitation

4 The cartridge/tonearm system acts as a lowpass filter for vibrations picked up by the stylus

5 Too low an effective mass for a given compliance (or too low a compliance for a given effective mass) results in low frequency attenuation and excessive tonearm motion.6Too high an effective mass for a given compliance (or too high a compliance for a given effective mass) results in "ringing"—a small resonant peak—that is largely benign
and barely registers in the measurements

Oddly enough he also provides a compliance calculator that gives results that are in direct contrast to his measured experiments.

dave