What is you tonearm’s Maximum Distortion?

@lewm 

I am skeptical in using the calculated number for anything other than crude relative comparisons and find the plots to be much more telling of the relationships at hand. Below are the plots for the table @optimize posted above.  From looking at the table the Löf B sure looks appealing but the plots tell a different story if you are at all concerned about the last track on an original Blue Note.

for reference, here are the plots of the "low distortion parameter manipulated" alignment @rauliruegas posted.   When using a similar alignment I have found no point in listening to the last track or two of a side.

I have found that that the traditional 2X weighting factor is not representative of what I hear and that the weighting should be more like 4X. It seems you really need to cheat things to the inner groove closer to Stevenson to get a full side of high quality reproduction.  The last little tidbit is in general the numbers from these charts need to be multiplied by a factor of 5-10 to actually be representative of a real world measurement.

dave

@intactaudio : " If the parameter manipulation is kept hidden then there is another term for it.. "

Well, don’t tell to me but directly to the SAT designer. The OP P2S 225.. was asking for better numbers and the SAT ones gaves it.

" I have found no point in listening to the last track ... "" that's at least untrue because the higher distortion happens only with the LP that has groove modulations  up tp 60mm ( inner groove ) and even that you don't know if could be aware of it due that distortion goes in increment or decreasing groove to groove and ears goes accustom to. Not easy todetct it. Don try to " satanize " it: bad attitude.

Btw, have you an alignment with no trade-offs? and if you don’t have it then maybe it’s the rigth time that you do it because you critic and critic but don’t give nothing in change. Yes, you are free to post whatever you want but could be bette to leaft to critic the standard alignments and show a no trade of alignment that we all can name intactaudio. Show something and stop critic because that critics goes not against me because I did not any alignment I only use it as all audiophiles.

Which tonearm/cartridge alignment are you using?

R.

@rauliruegas 

Well, don’t tell to me but directly to the SAT designer.

I do not have an issue where mark sets his null points and I do not believe he would fudge the inner groove radius to 75mm in the calculations to avoid showing the sharp increase in distortion once you get closer than 75mm.

 The OP P2S 225.. was asking for better numbers and the SAT ones gaves it.

Sure... if you use a little harmless parameter manipulation and substantially shift away from a standard set of inner/outer groove numbers you can get vanishingly low numbers.  

" I have found no point in listening to the last track ... "" that's at least untrue because the higher distortion happens only with the LP that has groove modulations  up tp 60mm ( inner groove )

This is akin to saying that a silent groove has no distortion.   JR @wallytools makes a compelling argument and has collected data to support a trend in newer records and audiophile reissues to basically leaving the last track off each side to avoid the issues with the inner groove.  He offers a protractor with dual alignments to take this into account and makes it very clear what his goal is.  The key here is he gives all of the information and lets the end user select what best fits their listening style.  Taken to the extreme I could even see a second arm being added to a setup to allow for two different alignments to match JR's observations.

Btw, have you an alignment with no trade-offs?

Nobody does.  I actually believe that there are far too many variables that cannot be set accurately enough to get any specific alignment and simply getting two null points on the playable surface is no small task.  I want to be clear that I am not being critical of anyones alignment goal.  Everyone is allowed their own choice of compromise.  My problem is presenting manipulated numbers without disclosing the manipulation to justify someones choice.

dave

While I do hear some inner groove distortion sometimes, I am grateful to the last track for giving me a bit more listening time per side.

As we see here in the graph below 👇

The Löfgren B has lower distortion all over the record surface except in the end just before lead-out starting. But we also know that a 12" LP always start at the same diameter but the 60 mm at the lead-out is something that they recommend that we stop to cut information closer to the label than those 60mm. The issue and problem is to:

1. Find appropriate track to put as the last one. On that A/B side. When the resolution is lowest there.

2. Because of the above we would like to make so that side A and B ends at the same radius. In other words it is not wise to end one side at ~80/90 mm and the other side at 60mm. If we could rearrange the track order so both of the sides end at 70 mm instead. For better fidelity.

3. Many 12" 45 rpm ends further out than 60mm and has a big area lead-out.

4. Do we push the envelope to go closer to the label than 60mm then we get issues with some auto stop or automatic return mechanisms in automatic TT.

So in short lead-in is more or less always at the same place but the same can not been said regarding lead-out, it is far from all 12" discs that end at 60mm when many ends future out for some of the reasons above. With that insight it is less of importance to optimize at just 60mm like Stevenson do in the graph below.

It seams that the consequences and penalty for having that aim is that having the lowest distortion from 60 to 65mm (were Löfgren B crossing Stevenson) is that Stevenson has higher distortion then Löfgren B from 65 mm and more or less the whole way until the start and lead-in of the disc!

That is a high price to pay and is only benefits if you has overture 1812 with canons at the end between 60 to 65mm or bolero and other crescendos in that area in many of your favorite albums may have.

Otherwise Stevenson is in my opinion something nobody should use. And maybe there is a reason why Lofgren calculated and created a second and improved version after his first attempt.

Here we see that this record side is actually close to 60mm:

And as you see it is those 5mm I "sacrifice" with my Löfgren B:

So it is not a huge "sacrifice" if now the lead-out starting at 60mm.

Or in other words someone that prefer those 5 mm to have the LOWEST distortion on the record has actually "sacrificed" and choose a higher distortion from those 65mm and the whole way to the start of track one!