Why the sudden popularity of 12 inch arms

The reason is, this Design can be sold. The world has to go round.
That's it.
And lots of Arms - even today- are not perfect, or have problems with bearings, work only well with some cartridges..., or the turntable is not able to show all differences or to bring out the best from every design ... there are various reasons.
When you don't believe it, buy a Phantom Arm and 2 identical Cartridges and the compare it. You will hear differences, but is the 12" (or all) really better?

To shed a little light and (I hope) not too much heat on this debate, I know from experience that Raul notices and values some aspects of audio reproduction while not noticing or valuing others as much. We all have listening biases of course, but some of Raul's may have a direct bearing on the issue being discussed here.

Raul does not much notice or care about two things that happen to matter a great deal to Paul and me: very low level detail and harmonic overtones. This was evident during his visit last year when we compared his preamp with ours. OTOH, Raul is very attuned to strong, tight extended bass and full dynamics, among other things. We each have our listening biases and those, IME, are his.

The reduced tracking angle error possible with a longer arm will be most audible in reduced HF distortion and tighter, more stable imaging. These are areas where Raul's sonic antennae are less sensitive than some others. Not a dig, just an observation.

OTOH, a shorter arm is (all other things being equal) less flexible and should therefore produce stronger dynamics and tighter bass. Raul is highly attuned to these areas, so in a shorter arm may indeed sound more lifelike to him.

Of course the materials and manufacturing advances referred to by Zieman and others may now indeed allow arm manufacturers to provide the best of both worlds. But I thought it might help understand the differing views being expressed if one participant's listening preferences were explained by a third party with no axe to grind in this particular argument.

Thomas, Yes I believe it is. You correctly suggest when employing as close to The Scientific Method as possible, one can A-B for oneself. I give credit to the engineers and designers to have done at least some of that for me. Reduced tracking error is a gimme. Materials and measuring tools, costruction techniques and equipment that were not available or affordable just a few moments ago, allow the theory to be realized in the form of product we can employ for more accurate reproduction. Competition for market share helps us pesky end users more able to afford this new advantage. Plus they look killer, remember? Z

Dear Shane: I can't comment ( for sure ) the why's of those reviewers because first than all its music/sound priorities are different for mines or even yours and second because almost all them are commercial biased and they have " to help " to that manufacturers grow-up.

The Ikeda ( crappy like you named. Obviously your know-how about is none. ) ) and Audiocraft are current tonearms. Shane with all respect to the designer I could say that your VPI is a crappy item against any of those tonearms, how can you name those tonearms in that way? do you already tested/try it two or three of them in your today system? how do you know which are its performance level?, IMHO you are talking only because you " want " but not because you are experienced on it or because you have personal facts where you can prove it and this is not only unfair but almost dis-honest.

Shane, you have to read again my post because I'm not against the 12" tonearms I'm only saying that the 12" tonearms are not better ones than the 9-10" only because are longer, that's all.

Regards and enjoy the music.
Raul.

Automobile "talk" bores me!!..Maybe Tennis talk,or how great the Giants were,beating the invincible Patriots.
The 12 inch subject,though valid,does not "get me going" all that much,mainly because there are some fabulous "shorties" that are absolutely amazing(like my new Phantom).Also,I respect Frank Schroder's opinions here,and he is not wild about the 12 length.
To me,from my own experience,the linear design is "absolutely" superior to any other alternative I've heard,and by a "long shot"!The only problem is the somewhat pain in tush pump/compressor,and periodic maintenance(not really a big deal,if you consider the performance,which is inarguably better,and clearly superior...PERIOD!).
If we want to look at Roy Gregory( a good writer,but has his own set of listening biases,like all of us),the recent interesting report in the last Hi Fi Plus,had a low priced(relatively)linear design "easily" competitive with some BIG TIME pivots.Some really amazing designs,AND the cheapo linear one,seemed to steal the show,from his description!...HMMMM?
Just some thoughts.