How much difference if the tonearm is mounted 5mm

Dear Dangcaonguyen:  """  I mounted the arm 5mm shorter than manufactor reccomedation. The result was terific.  """

IMHO what it's terrific down there are only " terrible " and high distortions not real music information.

Many years ago Löfgren makes a huge research and found out what after him was the flagship of a tonearm alingment ( you can search google for those white papers to understand the meaning/foundations of the theory. ) where vintage and today tonearms has each one tonearm specific alignment parameters.

What define those critic parameters ( overhang and offset angle ) is the tonearm pivot/bearing to spindle distance where for each PTS distance exist one and only one offset angle and overhang. Each time that STP distance change these two parameters change to aling correctly the cartridge in the tonearm.

Look, the difference between the Löfgren and Baerwald alignments with the same PTS distance is less than 0.6mm in the overhang where the offset angle stay the same in both alignments proposals. In this example the whole tracking error ( pivot tonearms. ) is different all over the LP recorded surface.

Here you are talking of 5mm!!  with out changing the offset angle!!!, so the tracking error goes up in exponential way"""" and that's what you are hearing.

Those gentlemans that gave you the advise to change the cartridge position through slots do not understand yet from where come those parameters values ( equations on the white papers. ) on overhang and offset angle.

Now, here you can read all referent to mount VPI different tonearms an you have to mount any cartridge on them through the VPI dedicated protractor and if you are in doubt then contact directly to VPI:

http://www.vinylengine.com/vpi-tonearm-geometry.shtml

and here you can read about calculators when you need a different PTS distance, overhang or offset angle:

http://www.vinylengine.com/tonearm_alignment_calculator_pro.php


or you can downland this calculator that gives you all you need to know about and know how distortions goes with changes in any tonearm/alignment parameter or alignment kind:


http://www.enjoythemusic.com/freestuff/BaerwaldLofgren88.xls


Regards and enjoy the music,
R.

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Dear Dang: So, you are saying that PTS distance is 207. Nothing wrong with that if the offset angle and overhang belongs to that PTS distance. You can see it here:

http://www.vinylengine.com/tonearm_alignment_calculator_pro.php?arm1=Arm+1&l1=ps&a1lv=207&am...

as you can read on that chart the arm1 almost follow the Löfgren alignment so it's right, no problem at all. Now, looks like the cartridge overhang is correct because even your protractor points and only you have to be sure that the cartridge offset angle has the same value in that calculator chart to have the levels of traking error/distortions for that geometry alignment. 

The distortion levels beteween a tonearm mounted at 207 or 212 mm from the pivot are almost negligible if in both cases the overhang and offset angle are in the right position. 

Don't worry what the tonearm manufacturer put on his tonearm specs because we can change the effective lenght of that tonearm if and only if we are sure thet the overhang and offset angle is right on for that geometry alignment choosed.

Now, if you are sure of all those critical parameters then your " terrifc " sound posted is just true musical information with distortions at minimum for that geometry alignment.

Regards and enjoy the music,
R.

Dear Griffit: "  I listen to records and know what I 'hear'! ", yes but what you don't know is the distortion levels generated for your choosed alignment till you use " white papers "/calculator of those white papers equations. 
Tonearm/cartridge alignment is just geometry not rocket science but even that you need to work with " numbers " where " subjectivity " is not enough.

Of course that if you don't care  about distortions levels then you can do whatever you want.

Regards and enjoy the music,
R.

Dear Dangcao: Sure that Lewm ( Hola! ) will give you a precise answer about your protractor.

In the mindtime you have to know that the Stevenson geometry alignment is the worst one of the 3 you mentioned because is the one that gives you the higher distortions/errors all over the LP recorded area but the last few indide mm. and I'm sure that other 

You can read it and see it through the link I posted and gave to you. I hope this time you really read it, is very important to understand the why's on this critical alignment issue.

http://www.vinylengine.com/tonearm_alignment_calculator_pro.php?arm1=Arm+1&l1=ps&a1lv=207&am... 


Regards and enjoy the music,
R.

Dear Griffit: "  He wasn't asking for a schooling in arm design theory but just a simple answer to what he discovered "

I totally agree but thing's are that I always post trying that in any audio subject where I have experiences not only say: " yes or no " but trying to learn more on that subject and that other people can do it.

We all will improve our audio knowledge level if we all understand where everything comes down, where is " generated ".

I'm sure that some of the gentlemans here and viewers of the thread already learned " something " on each single post in the thread and this ( for me ) is the right target in any audio forum.

In my case your contributions here do not gave any new " light " but through this thread I learned that the Dangcao protractor is for at least 3 different geometry alignments where the Lewm one ( same manufacturer. ) is only for Baerwald.

With all respect my sugestion for you is that instead to " blame " my posts will be better if you ignore it. How about?, sounds good: right?

Regards and enjoy the music,
R.

Dear Calvin: "  I have learned a lot from all of you since the thread initiated. "


Good!, that's all about.

Regards and enjoy the music,
R.

Dear Dangcao: Japanese " loves " that S geometry with foundation in that the climax , normally in classical music, happens at the end of a LP side and those clemaxes are recorded at higher velocity and at the end/inside part of the LP the forces are harder for the stylus/cartridge to track it.
So, the S  geometry " helps " for the " normal " distortions ( other than the geometry alignment ) be at " minimum in that part of the recorded area but we have to pay for it because only in that inside part ( few mm. ) distortions are lower but in all the LP area just from the begin the distortions are way higher tahn in other kind of geometry alignments.

Several of the vintage topnearm designs came from Japan.

At the " end of the day " in almost any tonearm you can make the tonearm/cartridge set up with the alignment of your choice. I don't know yet one tonearm that accept one and only one geometry alignment kind.

Regards and enjoy the music,
R.

Dear Stringreen: Some tonearms comes ready for the offset angle if you mount it according the manufacturer advise but if you want to change it then sometimes you need to twuist the cartridge to have the right offset angle.
MANY TIMES YOU HAVE TO DO IT BECAUSE YOU NEED THAT THE CARTRIDGE CANTILEVER BE STRAIGHT TO THE PROTRACTOR LINES WHERE SEVERAL TIMES THE CARTRIDGE CANTILEVER IS A LITTLE OFF POSITION WHEN BUILDED BY THE CARTRIDGE MANUFACTURER.

The tonearm/cartridge set up is a extremly critical set up where there is no " land " to even minimum errors/mistakes because fraction of mm. change for the worst the distortions levels and where those distortions happen.

I posted here that for the same cartridge/tonearm set up the difference between Löfgren and Baerwald alignment is less tha0.5mm on overhang staying the offset angle almost the same and if you go to the links I posted you will see in the charts how changes the distortions for both aslignments.

This kind set up permits CERO tolerances if we want minimum distortions. CERO tolerances is almost imposible to achieve  so we have to have extremly care to make this kind of set up everywhere in the " circuit of the set up ".

Regards and enjoy the music,
R.

Dear EBM: You can read some information of what I posted.

Now, if in that tonearm set up: overhang, offset angle and pivot to TT center spindle distance belongs exactly to a determinated geometry alignment like Löfgren, Baerwald or whatever then that " crappy " sound will not appears.

In one of my links ( VE calculator. ) I made a comparison between different PTS distance in specific for those 5 mm. The calculator gave us the values for those 3 parameters I name it  ( in both cases. ) and gave us the diagram where we can see the differences in distortion levels and if I remember when all those 3 mparameters are right the distoriton levels are almost the same. So, IMHO no crappy sound.

Regards and enjoy the music,
R.