Script for intermodulation distortion testing of vinyl playback, setting VTA ,Zenith etc by test record

[calle_jr]

Thanks.
I have the STR-112, it has duotones with 4kHz and 400Hz lateral and vertical, and 200 Hz lateral and vertical, all with different levels of the intermodulation.
I think the results from such a test can only be compared to tests with the same record.
Anyway, the vertical intermodulations would be interesting to optimize VTA/SRA.

 

[Balle Clorin]

using the script...IMD results from the DIN 45 452 VTA test record, f1+f2=1000hz track mat maximum VTA...with mat.
Quite close to the specified 23degree

 

[Balle Clorin]

Tacet test record Antiskating/tracking test, script attached ,rename .txt to .py and edit file to match your recording

and with the analogmagik tracking track

And Ortofon 50-60-70-80-90-100um track

L-R phase difference for fun

note recording levels may not be exactly the same, these are old files I had, but all is with the same MC cartridge and TT /arm

 

[Balle Clorin]

using, a IMD vs time script... on CBS STR-112 test record, Sadly none of the track fit the 120mm null point. The numbers seem high, maybe because i recorded without RIAA
e

The vertical IMD track reacts with higher distortion when rising the tonearm base 2.5mm

 

[Balle Clorin]

Here is the time series script.

If you have a intermodulation test record with vertical modulation it can be used to set VTA for minimum distortion, or more..
The problem when doing this in REW is that wow and flutter cause the calculation to miss the peaks and calculation becomes incorrect..
This script has configurable frequencies to fit several records and are tolerant to some w&F...
Does calculate main IMD components, but not higher orders above 2nd and 3rd

Try it on your CBS STR-112 for example

PS : script is made using AI, after 26 revisions I decided to end with this version

Record is LB202 from East-Germany
View attachment 481214

A digital test track comparing script and REW
View attachment 481215

Spoiler: Another record

View attachment 481227

View attachment 481228
CBS STR-112 same cartridge &TT as above
View attachment 481230

another script for time series phase difference and distortion, rename to py

Fun with vinyl measurements

Horizontal Trackng Angle, or Zenith , the thing that protractors help with Thank you... I'm not used to this abbreviation... (What are the current zero points—the compromise points of your tonearm—at what distances?)

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