Ikeda IT-407 tonearm geometry

@bukanova

 In most of the records crescendo occurs in the very end (at least in classical and jazz) so with cartridges like SPU which are not the best trackers I do feel more safe to have Stevenson as it less possible that it will damage inner grooves of record.

Exactly, i can only remind others that we have not only big "12 inch records, but smaller "10 inch EPs and "7inch singles. On smaller format of vinyl there is nothing located that far from the center hole, because the radious of the record is much smaller. I've posted about it before, on "7 inch records everything located in the field where on "12 inch located only last two songs maximum. Stevenson alignment is not for idiots. 

But anyway, most of us using at least two tonearms and we can compare one to another with different alignment methods. I have 4 tonearms in use, some with Baerwald, some with Stevenson, some with manufacturer's own alignment.  

Perhaps I’m an idiot with tin ears, but in my experience the sonic differences between the various alignment geometries shouldn’t be exaggerated. I use FR 64s and 64fx tonearms with the specified P2S distance of 230mm, which means that the geometry is Stevenson by default. This way I can use my FR7 and SPU cartridges with correct alignment. On my Audiocraft AC-4400, using a variety of cartridges in a variety of headshells (slotted or otherwise) I have experimented with the other geometries, including Audiocraft’s own (which is neither Baerwald, nor Löfgren, nor Stevenson).

The sonic difference between these various geometries was so negligable in my system and to my ears, that I decided to use Stevenson for the Audiocraft as well. This way I can use my cartridges in all three arms, without having to make changes to their position in the headshell each time they go from one arm to the next. Yep, I’m a lazy idiot as well.

In my own defense I should probably add that my Reed 3P tonearm with fixed headshell uses the Baerwald geometry. As much as I’ve tried, I’ve never been able to conclude that this set up sounds superior in any way to the others. If anything, I’d say Stevenson is preferable with classical music, as these composer guys like to go out with a bang. You may have noticed this usually happens at the end of the record side, where inner groove distortion is likely to be most severe.

Dear @sdrsdrsdr @edgewear : Löfgren was and is the gentleman who made the overall research that permits him to develops the formulas to make the critical tonearm/cartridge set up calculations parameters.

What wanted Löfgren to calculate?, two main data/parameters: overhang and offset angle.

He took 3 precise and know input data for the overall calculations: tonearm effective length, inner most and outer most groove distance/radious ( LP. ).

Löfgren main output data/parameters are: overhang, offset angle, both null points and by difference P2S distance.

But Löfgren made two calculations alignments: A and B where the difference in between is only in the overhang distance.

After Löfgren alignments several other gentlemans tryed two make their own kind of alignments but at the end almost all of them finished with exactly the Löfgren A alignment calculation. This was and is the case of Baerwald that is similar to Löfgren A.

From where took Löfgren those input data/radious? from the IEC standard that defined that those LP inner/outer radious are: 60.325mm and 146.3mm.
Exist, at least, other two radious standards: DIN ( Germany. ) and JIS ( Japan. )

Stevenson made two alignments: one similar to Löfgren A calculation and the " stupid " Japanese Stevenson alignment where he took the inner most groove radious as the inside/second null point, he defined that way this null point: coincide with the most inner groove.
This Stevenson alignment is the worst one of any alignment and not opnly because has the higher tracking error/tracking distortion levels in the LP surface recorded grooves but the last/inner 3mms. grooves but because in reality the higher tracking distortion levels are over all the LP surface due that those inner 3mms. are only when a LPhas recorded grooves from around 58mms. inner groove to end of LP.
How many of our LP’s has recorded information at 58mm. inner groove?

In the other side, all input/output Löfgren calculations parameters can be " manipulated " no matters what specs were given by the tonearm manufacturer. We can change it. We can have our self dedicated alignment with different paramenters and different tracking error and tracking distortion levels too ( normally higher. ).

@edgewear, you are not thin ears, in reality exist those differences but not something as " nigth and day " and we need to know what to look for to detect those differences and that our room/system have high or very high resolution.

Why I posted the word stupid to that alignment and people that use it?

Because for me any person that for very low knowledge levels on some specific subject ignores the true behind that subject is ignorant about but if through several years that same person mantained that kind of ignorance then the person is no more ignorant but stupid because has not the capacity to learn on that subject and with all respect Ikeda-san is one of this kind of persons.

I had the opportunity to know the king of stupids in this precise alignment subject and unfortunatelly belongs to this forum and as a fact are two persons that figth in between to achieve that title. The question here: who will win the title?

Btw, I owned the 407 too.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Technics engineers in Japan who designed SL1200G tonearm with alignment method that is very close to Stevenson (almost identical) must be very s****d then.

In my own defense I should probably add that my Reed 3P tonearm with fixed headshell uses the Baerwald geometry. As much as I’ve tried, I’ve never been able to conclude that this set up sounds superior in any way to the others.

@edgewear same here with my Reed 3p "12 with Baerwald and vintage FR and IKEDA with Stevenson

It's THD tonearm war and it have roots from nineties followed by small moving mass marketing campaign.