Help me understand compliance!

Actually bill, non compliance manifests itself as feedback, poor tracking and the stylus hopping right out of the groove.

Skip, lewm and chakster have it right. Chakster's suggestion about the HI FI News Analog Test LP is very important. You have a light medium arm.
It will match up well with the more compliant moving magnet cartridges like anything from Audio Technica, Clear Audio or Goldring. The Goldring 1042 is a favorite of mine. 

Compliance is a measure of the stiffness of the cantilever's suspension. It is analogous to an automotive suspension. Lets use a pickup truck as an example. Empty pickups (no load) have a choppy ride but if you load one up with a ton of brick the truck now wallows and bounces at a low frequency. That is it's resonance frequency. Add weight the resonance frequency drops, take off weight and the resonance frequency rises. The test record will tell you where your resonance frequency is. If it is too high you add a little weight to the head shell. If the cartridge is too heavy or the compliance to high the resonance frequency will be too low and you would have to remove weight (mass) which can be hard to do. So, it is better to start with a cartridge that might be on the stiff side as you can always add weight. But, any of the above moving magnet cartridges will be just fine. If you tell me how much you want to spend and I'll tell you which models to look at.

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.