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Phono Cartridge Response Measurement Script

ariendj

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I just measured the 1 kHz signal of the Denon record. It looks fine.

L->R: -33.2 dB
R->L: -36.2 dB

Both signals are out-of-phase which makes me think there is very little to do to improve it. It is also close the the Ortofon record of around -35 dB for each channel. So the result is different from the sweep.

View attachment 273433View attachment 273434
Very nice :) What Denon is this? The XG 7001 or the ST 105? What's the cart? MM or MC?

For nice and clean ( =easy to read) graphs I like to bandpass the signal in audacity. Conveniently that also removes all ticks pops and other artifacts.
You could also make a correction signal for your setup from this data, that could probably shave off another 10dB of crosstalk. It's pretty easy to do in audacity.

Whith that you can be sure that you're looking at the cutting head's crosstalk when you play an STR 100 and get, say, a 25dB crosstalk measurement.

I was just looking at Discogs for a few more ST 105 copies. There were two copies available in France. Refreshed the site and they were gone. Seems like we're being watched :D
 

Thomas_A

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Very nice :) What Denon is this? The XG 7001 or the ST 105? What's the cart? MM or MC?

For nice and clean ( =easy to read) graphs I like to bandpass the signal in audacity. Conveniently that also removes all ticks pops and other artifacts.
You could also make a correction signal for your setup from this data, that could probably shave off another 10dB of crosstalk. It's pretty easy to do in audacity.

Whith that you can be shure that you're looking at the cutting head's crosstalk when you play an STR 100 and get, say, a 25dB crosstalk measurement.

I was just looking at Discogs for a few more ST 105 copies. There were two copies available in France. Refreshed the site and they were gone. Seems like we're being watched :D
XG7001, a nice mint condition copy. Shure V15Vx SAS/B

Right now I have RIAA pre -> realtime click repair -> amp when I play music, and I am quite happy with that. But it would be good with an in-all software that could to various real-time corrections.
 
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JP

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Starting point L -24.44dB, R -35.79dB:

Denon DL-1000A 0.8g_110R_TRS-1007 No AZ Adustment.png


My third adjustment was the best I achieved with the Ortofon record, though my target was to optimize on the JVC:
  • Ortofon L -31.28dB, R -30.60dB
  • TRS-1007 L -27.78dB, R -30.49dB
Denon DL-1000A 0.8g_110R_TRS-1007 AZ Adustment #3.png


Final adjustment #6:
  • Ortofon L -34.43dB, R -29.68dB
  • TRS-1007 L -29.68dB, R -29.30dB
  • XG-7001 L -28.23dB, R -24.73dB (EDIT - Pilot tones from sweep tracks)
  • STR-100 L -19.69dB, -19.85dB
  • *EDIT* XG-7001 B Tracks 5 and 6: L -29.95dB, R -29.68dB
Denon DL-1000A 0.8g_110R_TRS-1007 AZ Adustment #6.png

Denon DL-1000A 0.8g_110R_XG-7001 AZ Adustment #6.png

**Note the FR looks strange on XG-7001 as I used RIAA bass emphasis which is not correct for this record.

Denon DL-1000A 0.8g_110R_STR-100 AZ Adustment #6.png
 
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Latest changes:
  • Added equipment info line to describe the capture signal chain.
  • Crosstalk @1kHz outputs on the console line.
  • Adjusted font sizes.

I think this thing is done. There are other things I'd like to add but they'll all take some time and aren't necessarily priorities.
 

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I think this thing is done.
I'm out of this thread for a couple of days and this, lol! Great job, JP! This is one of the great moments in record enthusiast history. Some may say you are little too late, but we all know that given the level of general discourse, you are actually way early! ;)

So what are your thoughts noq on the CBS test record? Does it just need something a 0.5dB bell EQ bump between 5-12kHz? (Above 1kHz.)
 

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Also, is anyone else getting this:
DELETE.png

The file info is in the graph for me. Next time you update it, JP, note the small typo: "normalize = Frequecny in Hz to set as 0dB in the plot"
 

Thomas_A

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Thomas_A

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Starting point L -24.44dB, R -35.79dB:

View attachment 273468

My third adjustment was the best I achieved with the Ortofon record, though my target was to optimize on the JVC:
  • Ortofon L -31.28dB, R -30.60dB
  • TRS-1007 L -27.78dB, R -30.49dB
View attachment 273469

Final adjustment #6:
  • Ortofon L -34.43dB, R -29.68dB
  • TRS-1007 L -29.68dB, R -29.30dB
  • XG-7001 L -28.23dB, R -24.73dB
  • STR-100 L -19.69dB, -19.85dB
View attachment 273472
View attachment 273473
**Note the FR looks strange on XG-7001 as I used RIAA bass emphasis which is not correct for this record.

View attachment 273471

Nice job,

I would say that the difference is quite small except for the STR100. A note in my case is that I use a unipivot arm, so platter/record must be perfectly level. I think 1 ° error would translate to -35.2 dB, which includes record inaccuracies/random variable "errors" along the track and cartridge motor precision.

Also sweeps may suffer from LF pollution, 1 kHz signals can be/are filtered to reduce noise. Despite that, along a 1 kHz signal track, you can get different results when sliced into parts.
 
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ariendj

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Latest changes:
  • Added equipment info line to describe the capture signal chain.
  • Crosstalk @1kHz outputs on the console line.
  • Adjusted font sizes.

I think this thing is done. There are other things I'd like to add but they'll all take some time and aren't necessarily priorities.
Great work! I have one small request, though. Could you add a hint on which graph is left and which is right? I know that I can get the info from the source code, but if I look at the graph in five years time, I'll probably have forgotten about that.
 
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Nice job,

I would say that the difference is quite small except for the STR100. A note in my case is that I use a unipivot arm, so platter/record must be perfectly level. I think 1 ° error would translate to -35.2 dB, which includes record inaccuracies/random variable "errors" along the track and cartridge motor precision.

Also sweeps may suffer from LF pollution, 1 kHz signals can be/are filtered to reduce noise. Despite that, along a 1 kHz signal track, you can get different results when sliced into parts.

XG-7001 Side 2 Track 5 and 6: L -29.95dB, R - 29.68dB. Interesting that track 6 had a consistent warble once per revolution. I'll have to check out my other copies.

They're all going to have erroneous signal, though as I'm measuring with FFT we can look at the frequency of interest and not be concerned about that. Filtering is needed when you're measuring VRMS or VPeak.

I found it interesting that FR between 7kHz and 20kHz improved as AZ was optimized on TRS-1007. I'll have to experiment with that more.

EDIT - I think it's trivial to hack together a time domain plot so that it's easier for people to look at the performance of the single tone tracks.
 
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Also, is anyone else getting this:
View attachment 273487
The file info is in the graph for me. Next time you update it, JP, note the small typo: "normalize = Frequecny in Hz to set as 0dB in the plot"

File info is supposed to be in the graph, but you've something going on that's shifting things around so that it's placed a bit low. Same issue you had with the legend when its location was hard coded.

Version 16.1 Beta Example 3.png


EDIT - I'm considering adding crosstalk to the distortion plot. The original purpose of this layout was a zoomed-in view of the amplitude plot.
 
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Great work! I have one small request, though. Could you add a hint on which graph is left and which is right? I know that I can get the info from the source code, but if I look at the graph in five years time, I'll probably have forgotten about that.

Nowhere aesthetically pleasing to put it. Also, it's pretty much a default with spectrum plots that blue = channel 1 and red = channel 2, and also rather standard that channel 1 = L and channel 2 = R.

Or, just remember red/rot = right/rechte.
 

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Think I nailed crosstalk with the Clearaudio test record. Exactly at spec. 270pF. No special gadgets, I just learned that if I put a thin plastic ring between the headshell and the cartridge to lower the left side, it evens out for most of my cartridges. I was able to confirm this with a Parks Puffin and Tacet test record a while back. Note that my other VN5MR styli behave a little different and don't dip at the end. I'll post the most common result as my official measurement.
VN5MR - CA-TRS-1007¹.png

VN5MR - CA-TRS-1007¹.png


Now I have to re-measure everything that I can with this record. Shit.
 
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Starting point L -24.44dB, R -35.79dB:

View attachment 273468

My third adjustment was the best I achieved with the Ortofon record, though my target was to optimize on the JVC:
  • Ortofon L -31.28dB, R -30.60dB
  • TRS-1007 L -27.78dB, R -30.49dB
View attachment 273469

Final adjustment #6:
  • Ortofon L -34.43dB, R -29.68dB
  • TRS-1007 L -29.68dB, R -29.30dB
  • XG-7001 L -28.23dB, R -24.73dB (EDIT - Pilot tones from sweep tracks)
  • STR-100 L -19.69dB, -19.85dB
  • *EDIT* XG-7001 B Tracks 5 and 6: L -29.95dB, R -29.68dB
View attachment 273472
View attachment 273473
**Note the FR looks strange on XG-7001 as I used RIAA bass emphasis which is not correct for this record.

View attachment 273471
Looking at your first attempt and attempt #6, do you think this accounts for some of the difference between our measurements?
 
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I can't say that there's causation there, and if there is, to what degree it may impact FR.
 

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prefilterfreq = 1
prefilterorder = 15

Cleaned up the high end for me. Nice.
ezgif-3-be74ce3f10.gif

VN5MR - CA-TRS-1007¹.png
 
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WAY too low. If that filter touches the high end response you've serious issues. It's best to not use it at all, but if you do 10 seems to be optimal - doesn't affect 20Hz response and no other ill effects that I've seen.
 

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Fascinating. Perhaps it has something to do with the servo tone arm. My 20Hz measurement is pretty much at around zero. I'll measure the cartridge on the non-servo Denon to compare.
 

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Fascination continues. The filter has no effect on the CBS test record output.

Shure V15 V-MR⁴ - Denon DP-35F - CBS⁸ - 1.png
Shure V15 V-MR⁴ - Denon DP-35F - CBS⁸ - 2.png
Shure V15 V-MR⁴ - Denon DP-35F - CBS⁸ - 3.png

Shure V15 V-MR (270pF) TEST RECORD COMPARISON.png
 
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