I believe the HiFi World tests are done by Miller Research. They usually do a good and thorough job. You can go to Miller research for more detailed information if you register there. The info by Shure is likely reliable as it was written by their cartridge designers. They do specify an SME 3009 II arm for some tests. You think the average audiophile sets up for playback better than these guys did for their testing? The other two links would appear to be less thorough, but all share showing that with higher level signals distortion is into the several percent range. Some show the various harmonic levels though you wouldn't trust them I suppose.
Not to put too fine a point on it but the 3009 arm is pretty antiquated. So yes, I would expect that
some audiophiles are going to have a better setup with less distortion. Not the least of which they might choose something a little nicer than the lowly Shures... see my point about loading just below!
I'd be far more trusting of the numbers if they provided the slightest clue about how they were obtained. I've yet to meet anyone that's perfect... leaving out the methodology is bad science. Its not even a point worthy of debate. At this point all we can say is that cartridges likely have some distortion but we don't know how much.
FWIW, all MM cartridges ring at audio frequencies and should be critically damped (loaded) for best performance. The odd thing is you rarely see audiophiles doing or talking about this (all Shures are MM BTW, and unloaded are going to ring (distort); 47K is *not* loaded!). LOMC OTOH does not ring at AF; instead resonants with the tone arm interconnect cable at RF frequencies. The loading you see so many audiophiles talking about has 100% to do with how sensitive their preamp is to RFI, and nothing to do with how the LOMC loads at audio frequencies. The loading resistor is detuning the RF circuit. Spend some time ringing cartridges with a squarewave generator and observing the results on a 'scope and this will be made abundantly clear!
Right now I am wondering how many people that think analog is not hifi have actually heard an analog system that is properly set up? For example did you know that surface noise is often a function of the equalizer rather than the LP itself?
Lower level distortion doesn't merely effect tone though it does this. It also effects perceived loudness. Of course the higher the level and more extended the harmonics the more audible the effect will be.
And contrast these tests with digital. Clip it and you get plenty of distortion. Anything short of clipping no real significant distortion to speak of at any time.
One of these formats is clean and transparent with high fidelity. Another is less than clean, less transparent and of moderately good fidelity.
Bold: We need to be clear about what is meant here as this statement can be easily misinterpreted. If by 'low level distortion' you mean lower ordered harmonics, you are incorrect. If you mean low level distortion that contains higher level harmonics or IM you would be spot on.
Italics: I guess it depends on what is meant by fidelity, likely a subject for a different thread. I don't see digital as hifi as it lacks bandwidth (I was taught that hifi was at least 20Hz to 20KHz). Not to say that isn't improving. Unfortunately digital clipping is more common than many would care to admit. With analog you get some fudge factor at overload that happens to play well with human hearing rules. So which is really hifi?? The one that more closely works with human hearing rules or the one that doesn't? Since after 30 years of digital recording its pretty obvious that clipping is here for the duration, we have to allow for it, assuming that we will never do that is placing your head well below your feet where there's plenty of granulated rock. This is an excellent example of a point I made earlier that we won't really be making advances in the art until we embrace what we understand about human perceptual rules rather than unrelated specs from our current testing regime.
