Fun with vinyl measurements

[Balle Clorin]

Or this,
I have it, extremely useful…for optimizing my belt driver turntable and comparing with others.

shaknspin

Not all turntables are created equal. Find the difference.

shaknspin.wordpress.com

Regarding test records( I have got 10 including B&K, CBS , Ultimate Analog, etc) my Clearaudio Trackability test record
is the best, it has a 15 minute long 3150Hz track!
But for W&Flutter and speed measurments, the Shaknspin is far superior

Shaknspin can also be used to see speed with needle in a groove, se what happens when I lower the cart onto the record ( JJCale music), the speed drops by about 0.05rpm, midway in plot just below. Lower plot is with no needle drop

 

[Balle Clorin]

Sorbothane Sheet under motor, new Leveling, talcum on belt, and change of groove in platter brought my Gyro back to its best performance, very happy..
A small speed adjustment now and it is back in top form.

 

[Taketheflame]

Hey all,

So I almost started a thread, but might (am hoping to) find the answers I seek in here.

I'm looking to measure the frequency response of phono cartridges at home with test records/Audacity. I've read of a few programs that can plot the frequency graph from an audio file, but I've also read that a Python script exists that can do the same thing.

I found a Python script shared earlier in this thread, but it might be more of a script for W&F measurements based on the post and adjacent posts? (I'm not an expert in Python/coding in general, I just know how to load libraries and run some basic commands).

I'm hoping someone here might have the script and be willing to share it? It would be greatly appreciated!

P.S: If anyone knows of a good software method of removing RIAA EQ (one of the test records I will be using is not RIAA encoded), that would also be highly appreciated.

 

[sergeauckland]

Hey all,

So I almost started a thread, but might (am hoping to) find the answers I seek in here.

I'm looking to measure the frequency response of phono cartridges at home with test records/Audacity. I've read of a few programs that can plot the frequency graph from an audio file, but I've also read that a Python script exists that can do the same thing.

I found a Python script shared earlier in this thread, but it might be more of a script for W&F measurements based on the post and adjacent posts? (I'm not an expert in Python/coding in general, I just know how to load libraries and run some basic commands).

I'm hoping someone here might have the script and be willing to share it? It would be greatly appreciated!

P.S: If anyone knows of a good software method of removing RIAA EQ (one of the test records I will be using is not RIAA encoded), that would also be highly appreciated.

Audacity has an RIAA remover, or by inverting it, adding RIAA. I use it remove RIAA from 78s I dub, before adding the correct EQ for the label.

S

 

[USER]

Hey all,

So I almost started a thread, but might (am hoping to) find the answers I seek in here.

I'm looking to measure the frequency response of phono cartridges at home with test records/Audacity. I've read of a few programs that can plot the frequency graph from an audio file, but I've also read that a Python script exists that can do the same thing.

I found a Python script shared earlier in this thread, but it might be more of a script for W&F measurements based on the post and adjacent posts? (I'm not an expert in Python/coding in general, I just know how to load libraries and run some basic commands).

I'm hoping someone here might have the script and be willing to share it? It would be greatly appreciated!

P.S: If anyone knows of a good software method of removing RIAA EQ (one of the test records I will be using is not RIAA encoded), that would also be highly appreciated.

The script is located here: https://www.audiosciencereview.com/forum/index.php?threads/mm-vs-mi-vs-mc.18636/page-60#post-1368728

That thread has all the information you will need.

If you are using the CBS test record or any record that utilizes a non-inverse-RIAA sweep use one of the attached Audacity nyquist prompt filters. The inverse-RIAA filter on Audacity is inaccurate. In fact, the vast majority of the ones found on the web are inaccurate.

Note that a 96kHz sample rate recording will get you the full 2nd harmonic distortion measurement. 192kHz will get you the full 3rd harmonic. 44.1 will be incomplete.

If you are going to share your measurements please provide as much information as possible, including cable capacitance in addition to that of the preamp setting. Otherwise they are not that helpful for the public at large. Having measured many cartridges I have found that channel matching is so unreliable--and often does not meet spec--that it is even useful to provide a channel inductance reading.

Good luck!

 

[Balle Clorin]

I have descibed my method earlier in this thread i think. Classic test record for frequency sweep - TRS1007- Are NOT RIAA but have bass eq but no eq above 1000hz. Luckily my Parks Audio Puffin has a selectable EQ that fits. You may record in REW and make / use a calibration file to linearise the plot. I have not tried Audacity for this


The Elipson test record has a full RIAA white noise track the gives the cart+preamp frequency response directly

 

[Taketheflame]

The script is located here: https://www.audiosciencereview.com/forum/index.php?threads/mm-vs-mi-vs-mc.18636/page-60#post-1368728

That thread has all the information you will need.

If you are using the CBS test record or any record that utilizes a non-inverse-RIAA sweep use one of the attached Audacity nyquist prompt filters. The inverse-RIAA filter on Audacity is inaccurate. In fact, the vast majority of the ones found on the web are inaccurate.

Note that a 96kHz sample rate recording will get you the full 2nd harmonic distortion measurement. 192kHz will get you the full 3rd harmonic. 44.1 will be incomplete.

If you are going to share your measurements please provide as much information as possible, including cable capacitance in addition to that of the preamp setting. Otherwise they are not that helpful for the public at large. Having measured many cartridges I have found that channel matching is so unreliable--and often does not meet spec--that it is even useful to provide a channel inductance reading.

Good luck!

Thank you so much! I'll spend some time reading through more of that thread soon.

Couple of quick questions for now if I may?

1. You mention using 24/96 or 24/192 sampling rates for capturing harmonic distortion, but I notice the script calls for 16-bit .wav files to work. Do you mean the native recording must be 24/96 or 24/192, but that the harmonic distortion information is actually retained when exported as a .wav file?

2. I have a CBS STR-100 on the way to me, but I already have copies of the Ultimate Analogue Test LP and the HiFi News Test LP here as well. Are those RIAA encoded? And I've read of some people saying the HiFiNews tracks aren't the most accurate with the sweeps or pink noise tracks - any comment on that?

 

[levimax]

Thank you so much! I'll spend some time reading through more of that thread soon.

Couple of quick questions for now if I may?

1. You mention using 24/96 or 24/192 sampling rates for capturing harmonic distortion, but I notice the script calls for 16-bit .wav files to work. Do you mean the native recording must be 24/96 or 24/192, but that the harmonic distortion information is actually retained when exported as a .wav file?

2. I have a CBS STR-100 on the way to me, but I already have copies of the Ultimate Analogue Test LP and the HiFi News Test LP here as well. Are those RIAA encoded? And I've read of some people saying the HiFiNews tracks aren't the most accurate with the sweeps or pink noise tracks - any comment on that?

1. The FR response is independent of bit depth but dependent on sampling rate so when you save the .wav file you reduce the bit depth to 16 bit but keep the sampling at 96 or 192.

2. The STR-100 is kind of the "standard" on the other thread because of the large number being sold cheap on ebay. You can read on that thread and other threads about the various test records and their issues. I have a terrible "Ultimate Analogue Test LP" which is off center. The good thing about STR-100 is that there is enough information to help separate the defects on the records from reality.

 

[Balle Clorin]

A borrowed from the net a new filter method used for my ShaknSpin RPM checker(. Excel data import). Showing turntable speed variation data

But for the orange plot above :should the Butterworth filter be by power(squared) magnitude (H^2) or just magnitude response (H)? I see people use both, but what is correct for speed variation data

 

[JP]

1. You mention using 24/96 or 24/192 sampling rates for capturing harmonic distortion, but I notice the script calls for 16-bit .wav files to work. Do you mean the native recording must be 24/96 or 24/192, but that the harmonic distortion information is actually retained when exported as a .wav file?

It's an old note and there must have been a library update as I've been using 24 bit files for a year or so. Not that 24bit is required, it's just what my setup captures in by default.

2nd harmonic of 20kHz is 40kHz and the 3rd harmonic is 60kHz. If you want to capture 60kHz you need a sample rate that's at least twice that.

 

[USER]

Thank you so much! I'll spend some time reading through more of that thread soon.

Couple of quick questions for now if I may?

1. You mention using 24/96 or 24/192 sampling rates for capturing harmonic distortion, but I notice the script calls for 16-bit .wav files to work. Do you mean the native recording must be 24/96 or 24/192, but that the harmonic distortion information is actually retained when exported as a .wav file?

2. I have a CBS STR-100 on the way to me, but I already have copies of the Ultimate Analogue Test LP and the HiFi News Test LP here as well. Are those RIAA encoded? And I've read of some people saying the HiFiNews tracks aren't the most accurate with the sweeps or pink noise tracks - any comment on that?

Basically what Levimax said. I use 32-bit files, but it doesn't matter.

As far as the CBS record goes, basically at this point it seems that it and the impossible to get JVC test record are the best test records available for 1-20kHz. My own suspicion is that the CBS record is the best test record available if one ignores the built-in errors at 5kHz and between 10-20kHz. The latter is test record specific and it takes some work to find a good-enough copy. Luckily they are cheap and you can try out a few of them. (See the thread for more info.) But, as of now, *I* like it better than the JVC test record *IF* one can get a good copy.

JP actually has one of my cartridges and is testing it out on his JVC record for a direct comparison. I think he will also try out the CBS records again at some point. In my opinion he may soon have the best data set to have a sort of "final word" on these test records.

 

[Balle Clorin]

A borrowed from the net a new filter method used for my ShaknSpin RPM checker(. Excel data import). Showing turntable speed variation data
View attachment 250178

But for the orange plot above :should the Butterworth filter be by power(squared) magnitude (H^2) or just magnitude response (H)? I see people use both, but what is correct for speed variation data
View attachment 250185

View attachment 250187

Have to reply to myself here

 

[Taketheflame]

Well - it looks like I'm having some trouble with getting the RIAA-removal plug-ins shared by USER to work.

After extracting the files to the Audacity plugin folder and opening Audacity, I get a message showing the new files but saying they are an incompatible file type. Trying to go into both plugin manager and the Nyquist plugin installer to enable them yielded the same results/error messages. In the case of going to the main plugin manager, I get a message saying "Failed to register - Ill Informed Nyquist plugin header".

I'm using version 3.2.2., and using Windows 10. I've tried uninstalling and reinstalling Audacity in both 32-bit and 64-bit versions with no luck.

I get the feeling I'm doing something wrong, but am curious if there's some kind of workaround, or if maybe these Nyquist files will only work with older versions of Audacity or other operating systems?

 

[USER]

No need to put them in the plug in folder. You simply highlight/select the audio, go to Tools, Nyquist Prompt, Load (respective file), and click Apply.

 

[Balle Clorin]

The belt matters

Luckily Malvern do not sell these belts anymore

 

[Balle Clorin]

How does a really cheap MM cartridge perform, Thorens TPU 257=AudioTechnica AT-3600= close to Rega Carbon

Thorens TAS 257 - Muziker

Thorens TAS 257 ✓ Best Price Guarantee ✓ Fast shipping ✓ Return policy up to 30 days ✓ Professional customer service ✓ 25 years on the market

www.muziker.co.uk

The only problem with this cartridge is the high tracking force at 3g, that will wear the records

Clearaudio TRS-1007 test record

Channel balance and separation is much better then the specs

 

[JP]

Can I get the file for that OC9II?

 

[Balle Clorin]

@JP , Use the calibration file to make horizontal spectrum plot. The zip file uploads, but disappears?
Error message too large

Instead import the wav file as"import audio data" and apply the attached calibration file to linearize the spectrum plot.
That failed too,,
what am I doing wrong?

 

[JP]

Just the audio of the sweep - one channel is fine at 16/44.1. If too large you'll need to use a file sharing service/google drive/one drive/dropbox, etc.

 

[atmasphere]

How does a really cheap MM cartridge perform, Thorens TPU 257=AudioTechnica AT-3600= close to Rega Carbon

Thorens TAS 257 - Muziker

Thorens TAS 257 ✓ Best Price Guarantee ✓ Fast shipping ✓ Return policy up to 30 days ✓ Professional customer service ✓ 25 years on the market

www.muziker.co.uk

The only problem with this cartridge is the high tracking force at 3g, that will wear the records

Clearaudio TRS-1007 test record
View attachment 251716


Channel balance and separation is much better then the specs
View attachment 251717

The peak at high frequencies is caused by the electrical resonance created by the inductance of the cartridge in parallel with the tonearm cable capacitance (and whatever capacitance is present at the input). You can flatten this out by proper loading.