Pivot to Spindle distance

elliottbnewcombjr"Why aren't all overhangs the same you might ask?"

Why aren't all tonearms 23cm long why aren't all tires the same profile?

@markpao , don't bother Mark. As long as you have the right offset and overhang with the cartridge you are using you are in business. If the cantilever is parallel to both sets of lines then all of the above is true. The P2S distance is just to get you in the ballpark. You have already found your seat. Stay there. You just risk damaging something playing around.

Longer arms are not a panacea. They have a greater polar moment of inertia which causes much more distortion than any improvement in tracking error can resolve. This is why many of us prefer shorter arms and why many tonearm manufacturer's scratch their heads in response to this market demand. There are very few modern cartridges that require tonearms that heavy. 

fsonicsmith, I admit to being overly inquisitive at times, in my search for clarity, but on this thread, all I asked for was the OP to explain the very vague term he used to indicate he was satisfied with his alignment despite the known 5mm error in P2S ("pretty good"). I am an alignment nihilist, almost like MC, but I do make the effort to get it right, once. After that, I just listen. Like the OP, I have had the experience of accidentally discovering after the fact (and after listening to LPs for hours and hours) that I made an error in P2S distance. On that occasion, I fixed the problem and thereafter could hear no increase in my already high level of listening pleasure, compared to the hours I had spent with the misalignment. But I felt better.

To MC’s point, how many posts do we see where some guy describes a mysterious problem with his phono SQ? Those posts are almost invariably followed by suggestions that he check his alignment parameters. This is evidence that most of us are true believers. Conversely, when said complainant goes off stage and "fixes" his alignment, he almost invariably comes back to us to say how wonderful his LPs now sound, thanks to his having tweaked his alignment. I don’t know whether this is evidence for or against MC’s hypothesis. As you know, I am a big believer in subconscious bias that affects our listening.

Normal people usually set up PS first and then align a cartridge in the headshell slots using chosen cartridge alignment method (Baerwald, Lofgren, Stevenson or whatever it is).

Some people do that other way around? 

If your PS is wrong and tonearm already screwed to the mounting hole (and you can’t move it), then your chance to reach desired null points by moving your cartridge into headshell slots forward or backward is very little, sometimes it’s simply impossible! Or it’s possible just with 1 aligning methods of many (and probably not the one you wish to use).

Headshell lots are different size, depends on the headshell model.

Some headshells have fixed screw holes (you can't twist a cartridge in such shell changing alignment method).

Tonearms without removable headshell will give you even less possibilities, sometimes the slots are very small.

So the BEST method is to start from correct PS (always) !

clearthink1,179 posts02-10-2021 11:50amelliottbnewcombjr"Why aren’t all overhangs the same you might ask?"

Why aren’t all tonearms 23cm long why aren’t all tires the same profile?
...............................

Why can’t all people think clearly?

Joking aside, I am curious: different arms, same P to S, will have different overhang specs. What’s the process/science that leads the designers/engineers to those differences?

I thought by asking: dazzle em with brilliance or baffle em with bullshite would occur.

I thought some interesting links might be posted.