Spindle-To-Pivot Distance

If you are looking  for a answer to your question  you probably  came to the wrong forum.   Some engineers  way  back in time came up with the two null point system and the various percentage of distortion  from there.  There  seems to be 2 to 3  popular  null point systems.  So if  you go by there  methods you have 2 null point with everything  is supposedly  perfect and the rest  goes into various  degrees of distortion.   Love to meet the guy ,without seeing the  record, who could pin point the null points with his ears.

Now you are talking 10mm which is  a pretty good distance.   If you have  reasonable math/ engineering  skills you can go to vinyl  engine and use there calculator  to see if you can get 2 null points and where they would be  using the 240 and  250 mm  mounting  distance.   Then maybe take  a record that  did cost 100.00  and try it  at 240 mm.  

I do not know how  involved  you wanted to get  but  thought  I would give you the option  to be able to understand  a little bit  of what is going on.  There are  guys on other forums  who will do the math for you or  run the calculators for you.

Enjoy the ride 
Tom

Lewm you brought up the question  that 1st popped  in my head.   Could you move it  10mm  and still have 2 null point.  With the calculator  on vinyl  engine  you should be able  to solve with the variables  he knows.  He could also go to vinyl  asylum  and ask John Elinson (sp)  he has his own spread    sheets.  He could figure this out quickly  and will recommend  to play by the rules.  

As a side note I have been playing around with 2 of my 14 inch arms  with no offset  and 1 null point.  Seems to be a little more dynamic.   If the average distortion is higher  it  is not apparent.   Need to really  sit  down and listen and go back and  forth.   Took up  Kayaking last year  so haven't  been building and listening much.

Enjoy the ride
Tom

PS.  I like the looks  of a cartridge  all the way forward in the head shell.  Although  I  don't remember  the OP  asking  about  this issue.

Lewm  the arms are my own.  The ones with the zero offset  are Brazillian  rosewood with a straight  aluminum headshell.  I use a spacer block of aluminum  or wood for now, between the cartridge  and headshell,  so any angle is available including  zero.   Better check the blood pressure  at the rigid camp.  In fact if you showed them your  RS tone arm you would have to take them to the emergency  room after they see the headshell can move.  Need we forget it wobbles  with no silicone  and  the  pivot is  no where near where it should be.   

The 2 arms are  the same table.  One is rigid on plinth  the other on a massive pod.  Oh dear  the rigid camp is going to lose it.  Now  something that make a real sonic difference  is I can run my tables  either  belt/tape or  idler.  Can change back on forth  around 5 minutes.   Even the  density  and thickness  of the o'rings can change the sound.  Go Figure!!!

Well I went a little  off topic but I hope  the OP gets  what you brought up  about  Did the so called Masters of the old days, using mono,  know  what sounds the best or just like whatever the machine told them.

Enjoy the ride
Tom

Rauliruegas if you read through the posts carefully  you will see  both lewm  and myself  are questioning  the null point concept.   I  am not sure about  about  how important  the whole thing is.  You might want to listen to a RS tonearm and  see it breaks all of the status quo rules yet still sounds spectacular.  

Maybe  have a person  get a album you are not  familiar  with then have him play it  choosing different  spots , with you not looking.  Then  tell him where the  null points are on it .  Then you will know first hand  if you can  or if it matters.  Another  test would be have your friend  change the offset on the cart then play album.  Have them change the offset around  including the right spots.  Write down you hearing findings then compare  notes with  his placements. 

When I did  the test the two arms where attached  to the same table and if you noticed  I  said I really did not do enough testing to give you a  any  real findings.  But I can say I  have not  heard any wild distortion  issues  with underhang and 1 null point.  

I realize  humanity  wants absolute  answers to all their questions  but music reproduction  has far to many variables  to  be able to do the the  math run the test equipment  and have great sounding gear.

So back to the OP  all the stuff was brought  up  give him some ideas different  than the status quo.  Weather they are better or worst  is up in the air.  You already know they move the null points around  so where are the perfect spots.  

Enjoy the ride
Tom

Rauliruegas  it is simple  do the test I wrote  about.  The rest is possible  hypothesis.   Also  , while your at it , let's know at what level of distortion  you hear  things going to hell in a hand basket.  Remember  the 2 null spot are just that.  So only twice in a very brief  period  of time do we have the distortion  free  music.

Enjoy the ride
Tom