Why the sudden popularity of 12 inch arms

Raul, Please read my response again. Slowly. I changed one component. The only proper way to evaluate a new addition. I could hear the geometry change with my other arm. If you have your Lustre set up properly, you will hear it too. This 312 is light years ahead of our beloved 801. In addition to the geometry, it is quieter, faster, and more detailed. I suppose you could say the 312 matches my cart better, I am not using a 25 year old cart with my 25 year old arm! Z.

Zieman, it's not my place to walk Raul's dog for him so I'll offer a comment for all to consider.

You may have changed only one component but you changed multiple parameters. Not only degrees of tracing error but also mass, stiffness, bearing design and quality, resonant frequency, and wire (considerations just off the top of my head). I hope no one would disagree that you heard improved sound. But so many factors are involved that it is not fair to attribute that improvement solely to a longer arm.

From reading Raul's post slowly, that is MY conclusion.

Pryso, The original question was why the 12s are back. I thought I answered fairly well in my first response. Perhaps only five years ago a 12 inch arm would NOT have shown this dramatic an improvement. Again, (slowly) I think that many former disadvantages to the 12 have been eliminated. Materials research and manufacturing capabilities have not stood still. As far as I know the laws of physics have. Z.

Well, I think, there are some reasons why the 12's are back.
Mainly based on marketing reasons, because they can be sold.
That's it.
The technical reasons, well, most manufacturers are not stupid, they know how to build a good arm, some offer both, sell both and honestly, who cares. Some of them say, no one needs a 12 Arm, some reviewers write, they can not live without one....
In a way, it is like Raul wrote, when you have the perfect match, no one cares. Some time ago I listened to such a match and honestly, I simply couldn't believe it. It was a old FR64 Arm with a Koetsu on a real super Turntable.
When I closed my eyes ( a "Blind test" ) I really thought " I'm listening to an Air Tracking Arm". But, the Table was really a good one.
Some Arms can compensate Errors from the Turntable/Cartridge more or less, but at the end of day I think, the 12s look cool.

Zieman, I have no problem with your answer to the OP. The point I was attempting to make was the caution that a 12" arm will not automatically be an improvement compared to a shorter arm. Some might infer that from your post, particularly with your emphasis that only the arm was changed.

There are many design/construction differences between your 312 and your Lustre and I believe that was one of your points. That supports the position Raul has stated many times - many elements come into play in matching a cartridge with different arms. For whatever combination of reasons, your cartridge sounds better in your 312. One should not assume it was just because your SME is 12".

I believe you understand this so I was trying to offer a clarification to readers with perhaps less experience. Peace.