Phono Cartridge Response Measurement Script

[Thomas_A]

I don't think so, he has a point.

I know @JP records it flat. No strange results there.

Look. If you record flat, bin FFT, find the amplitude of frequency+H2+H3 , multiply all amplitude values with the record-specific EQs what do you get?
If you record with RIAA and perform inverse RIAA filter before the above steps, what do you get?

 

[JP]

I don't think so, he has a point.

I believe he's speaking in the practical sense of what goes in vs. what gets plotted. A lot of the confusion is fostered by a complete misunderstanding of how EQ is handled by the script, which I've answered at SHF. Frankly I'd rather leave the ball of confusion over there than recreate it here.

 

[ray_parkhurst]

I think the question has been answered over there. The problem came about when the "inverse" RIAA was applied manually, and the 10kHz attenuation was used on both its H2 and H3 rather than the correct values from the curve at 20kHz and 30kHz. I plan to use the numbers from the graph rather than any post calculated values, though I may dabble with flat recordings to see if the results are more consistent.

 

[USER]

I think the question has been answered over there. The problem came about when the "inverse" RIAA was applied manually, and the 10kHz attenuation was used on both its H2 and H3 rather than the correct values from the curve at 20kHz and 30kHz. I plan to use the numbers from the graph rather than any post calculated values, though I may dabble with flat recordings to see if the results are more consistent.

As has already been explained to you guys, you aren't going to get much concrete distortion information from the CBS test record. At least nothing that can be taken seriously here. The issue is especially problematic during the beginning stages of wear as distortion information remains hidden due to the limits of the test record. Here you see at least a 5 dB difference in many places. You likely cannot see the early stages of distortion degradation. You will have to be very careful about spreading misinformation.

 

[JP]

They been advised numerous times of the many flaws in the approach @Thomas_A. You’d think things like the once-per-rev eccentric in the distortion amplitudes would be a giant red flag.

 

[ray_parkhurst]

As has already been explained to you guys, you aren't going to get much concrete distortion information from the CBS test record. At least nothing that can be taken seriously here. The issue is especially problematic during the beginning stages of wear as distortion information remains hidden due to the limits of the test record. Here you see at least a 5 dB difference in many places. You likely cannot see the early stages of distortion degradation. You will have to be very careful about spreading misinformation.

Yes, I do see a lot of variation. But I don't remember any better suggestions. Perhaps some can be suggested for the next study. It's too late for this study to make any changes. Interestingly, the ML stylus is wearing very quickly, so there will be opportunity soon as I do plan to follow this study up with additional ones.

I initially had decided to use the STR-130 and do realtime capture of the sweeps and distortion, but ended up being convinced to use the STR100.

Edited to add: I am wondering why, if the STR100 is so useless, make the script available to analyze its data at all. There is even a plug on the portal asking folks to consider sharing their results on this forum. You say "nothing that can be taken seriously here" but this seems a big disconnect. If I go to the cartridge measurement database, how many of the cartridges are measured using the STR100?

 

[ray_parkhurst]

As has already been explained to you guys, you aren't going to get much concrete distortion information from the CBS test record. At least nothing that can be taken seriously here. The issue is especially problematic during the beginning stages of wear as distortion information remains hidden due to the limits of the test record. Here you see at least a 5 dB difference in many places. You likely cannot see the early stages of distortion degradation. You will have to be very careful about spreading misinformation.

You posted some plots as recently as Oct 31 in the "Phono Cartridge Measurement Library" that were generated from the STR100, including H2 and H3 results. This seems somewhat hypocritical, no?

I really do want to get good data on these experiments, but would like consistent and constructive input. As I remember I faced contradictions and such back in the original thread announcing SWS2, and gave up trying to get anything useful at that time from this forum, but I have an open mind and am willing to try again.

What test LP do you guys suggest?

 

[JP]

Not in this thread. Take it elsewhere.

 

[ray_parkhurst]

Isn't this the thread where the script is discussed to analyze data taken with the various test records?

 

[JP]

Not fundamentally flawed analysis, no.

 

[USER]

You posted some plots as recently as Oct 31 in the "Phono Cartridge Measurement Library" that were generated from the STR100, including H2 and H3 results. This seems somewhat hypocritical, no?

I really do want to get good data on these experiments, but would like consistent and constructive input. As I remember I faced contradictions and such back in the original thread announcing SWS2, and gave up trying to get anything useful at that time from this forum, but I have an open mind and am willing to try again.

What test LP do you guys suggest?

Ray, this is a frequency response measurement script and not a stylus wear distortion measurement script. Please don't deliberately play coy. We have a strong understanding of the limitations of all the test records. The CBS test record 1. gets us close to what is important for our needs in a known way and 2. is one of the only test records available to people. Anyone that has put a little bit of effort in reading simply the first page of the library thread will understand this.

And, again, as you have been told, your experiment is problematic because you are removing the cartridge to take pictures. As your old measurements show you guys never put the cartridge back the same way and your crosstalk and distortion results are inconsistent because of this. Do one and then the other --at least at the beginning-- so you can get reliable data with which to build on. But you guys seem to want to take as many shorcuts as possible, especially when it comes to understanding what the script does.

You may want to continue dialogue, but my previous engagement (a lot of time, effort, and patience) left such a bad taste in my mouth that *I* am no longer interested in your project. Let it be clear: I do appreciate the photograph portion of you project (what you yourself have contributed) very much. That is extremely well done to my eye.

 

[JP]

Not this thread. Please.

 

[ray_parkhurst]

And, again, as you have been told, your experiment is problematic because you are removing the cartridge to take pictures. As your old measurements show

As a final note (don't worry JP, I'll go away) I am only removing the stylus from the cartridge, not the cartridge or the headshell. I'm fairly sure the stylus goes back to a consistent reference position each time, so should be repeatable.

 

[DrCWO]

Hi @JP,
this morning I successfully used SJPlot with the MS Edge browser to adjust the azimuth of my tonearm.
Worked great, thank you very much for your work

 

[GuidoK]

As a final note (don't worry JP, I'll go away) I am only removing the stylus from the cartridge, not the cartridge or the headshell. I'm fairly sure the stylus goes back to a consistent reference position each time, so should be repeatable.

I think if you want to see how (harmonic) distortion is affected by stylus wear, you first have to find the measuring source that gives the least amount of distortion from itself, and that could become pretty important very quickly.
For example: Jico states that a stylus is worn out at 3% thd at 15khz. So without knowing what type of numbers to expect that'll actually happen in your study, that's -30dBV
If you look at the plots from @USER not even the ca trs 1007 record can measure that, in fact it sits 10dB above that so adding that 3%THD probably won't even show realistically (let alone to calculate how much it is), and that's for a fully worn stylus (according to Jico). I have no idea how Jico measures that figure, but as you're probably gonna run your experiment only once, getting a method to measure harmonic distortion with as much resolution as possible will probably be very important for the outcome of your experiment.
For that last one you could look at the tacet vinyl check record. It doesn't have a sweep but it has multiple tonebands and imho they measure quite low in distortion.
But in the end the amount of distortion is I think quite a rabbithole, as a louder test signal is more difficult to track at the same frequency than a quiteter one (so probably gives more harmonic distortion), but it's delta with the noise floor of the record etc is also greater so that noise floor has less of an impact on the measured distortion.

Also I think you should consider the question whether or not you should be looking at harmonic distortion to asses wear.
If wear results in mistracking, and if I listen at the Tacet IGD tracking test, harmonic distortion is not what in the first place comes to my mind (I wonder if I could actually hear harmonics of the S and F sibilants and fricatives frequency wise).
That test is imho for a lot of stylus shapes quite useful to asses wear btw. However it's not a numerical test, it's a listening test.

 

[JP]

Jico states that a stylus is worn out at 3% thd at 15khz.

So you've seen this statement directly from Jico? Where?

 

[JP]

Hi @JP,
this morning I successfully used SJPlot with the MS Edge browser to adjust the azimuth of my tonearm.
Worked great, thank you very much for your work

Yesterday there were four sessions with analyze_audio_click events but no plot_image_display events, all associated with script errors and all from a single user.

The plan at some point is to make a light analytics dashboard that anyone can view, GA and GitHub Pages having the right hooks to easily integrate it.

 

[levimax]

So you've seen this statement directly from Jico? Where?

yes https://www.jico-stylus.com/change-stylus/

 

[JP]

yes https://www.jico-stylus.com/change-stylus/

Searching the page for 3% and 15kHz yields zero results. You'll need to be a bit more specific.

 

[levimax]

Searching the page for 3% and 15kHz yields zero results. You'll need to be a bit more specific.

Sorry I was searching for the "hours" recommendation as in the past I know I saw the hours and method on the same web page. In the past JICO had another page that spelled out the "hours of life" for the different tip configurations and on that page they mentioned 3% distortion at what I remember to be 10 Khz .... could have been 15 Khz but not what I remember. It appears this page is not longer available but the "hours" recommendations still remain. I guess I could try "go back" to find the old page but not right now.