Fun with vinyl measurements

[morillon]

I see now that my writing was not clearly. I had 2 pots to adjust. To make 2 voltages/sinus on the scope to X volt. Both interacts on the result, so I adjusted a tiny amount on one and then the other, alternating. If I tried to correct one sinus curve/voltage fully , and then the other, I never got both values right. This was a Hall motor on the Sony PS212

I find this useful for quick unweighted WF check while adjusting.
View attachment 395024
View attachment 395027
The NAK T-100 software is also useful for online measurements during adjustment, if test record can be used.

0.04...
what standard? 2sigma? etc ;-)

android
"turntable speed" ( snakerule)
(ps: as a precaution, desinstall and reinstall if an old version ;-) )


It's good that there are solutions valid for Apple or Android... good help for adjustments and optimizations...

;-)

 

[Balle Clorin]

0.04 peak deviation , kind of close to 2S which is 95% if samples less than 2S value

 

[morillon]

0.04 peak deviation , kind of close to 2S which is 95% if samples less than 2S value

(Is this one of your dd ?)

 

[Balle Clorin]

Finally I found a figure that illustrates why/when crosstalk shifts from being In-phase with main signal, to out-of phase.
The figure shows a situation where the Azimuth is at an angle that gives In-phase crosstalk. Imagine the angles tilted more anti-clock wise, ( Azimuth adjustment) then the arrow for the crosstalk will change direction , and therefore the crosstalk will mecome out-of phase.

Optimal Azimuth occurs when cross talk switches from in phase to out of phase. At that point the crosstalk should be at minimum and colaen to equal.

 

[Balle Clorin]

(Is this one of your dd ?)

My Michell Gyro SE belt drive, on a good day. it takes some effort with the set up to achieve this..

 

[morillon]

My Michell Gyro SE belt drive, on a good day. it takes some effect with the set up to achieve this..

(I also have at best 0.04% 2sigma and 0.03 rms which passes.. but not significant....old vpi AC no reg)

 

[USER]

I'm optimistic this Sony PS-X60 will be an improvement over my PS-X50 after it is refurbished. (Well, not an audible one, but at least a nerdy numbers one.) Hoping too that the squarish shape is pointing to either minor electrical adjustments or capacitor replacement. It's always a good thing to run a quick check-up when a used turntable arrives and before you open it up!

 

[Balle Clorin]

Cannot recall test record name,,horrible wow and uncentered, can it be HifiNews?
Edit: yes it must be. .but this one

HFNRR Test record

The famous HiFi News and Record Reviews test disc: how to properly install and tune in your analog turntable, test on TNT-Audio - Internet HiFi magazine

www.tnt-audio.com

Track two and three are sweeps from 25-5 Hz along with a 1 kHz tone. Track two is in phase so gives a horizontal movemant at the stylus, track three is out of phase so the movement is vertical. It sounds complicated but what happens is this... You'll hear a tone and a voice counting down the frequency. At some point the tone will "warble" and the cartridge wobble visibly. This is the resonance frequency of the arm/cartridge.
If the resonance is too low - say 6 Hz as with a very compliant cartridge and a high mass arm the result is a cartridge very sensitive to footfalls and a sod to cue. On the other hand if the resonance is to high - say 20 Hz as with a low compliance MC cartridge and an ultra low mass arm the resonance will be audible and will colour the sound. Though this test does tend to spot when you've bought the wrong equipment it can also show the effects of changes in damping.

 

[morillon]

It's better to put a frequency meter in parallel because the voice/frequency setting is hardly relevant..offset
;-)

 

[narud]

big thanks to @Thomas_A for guiding me through looking at distortion of single tones over at the hoffman forum. i used my shure era v test record with trackability tests that use a combined signal of 200hz, 2.1k and 17k, filtered out each frequency and then looked at the distortion of each. comparing my v15vmr which has about 600 hours on it to a vm95ml with under 100, the distortion was similar at 200hz and 2.1k but there was a big difference between the two at 17k. i would have never thought to look at that before.

 

[melloncolliecat]

For 0-20 Hz @Quando - just check the lead in groove before the 1 kHz test tone, or otherwise the silence between the 1st and 2nd sweep. Zoom in on the lower freqs and you'll very likely see a peak somewhere in the 6-12 Hz ball park.

 

[Thomas_A]

Cannot recall test record name,,horrible wow and uncentered, can it be HifiNews?
Edit: yes it must be. .but this one

HFNRR Test record

The famous HiFi News and Record Reviews test disc: how to properly install and tune in your analog turntable, test on TNT-Audio - Internet HiFi magazine

www.tnt-audio.com

Track two and three are sweeps from 25-5 Hz along with a 1 kHz tone. Track two is in phase so gives a horizontal movemant at the stylus, track three is out of phase so the movement is vertical. It sounds complicated but what happens is this... You'll hear a tone and a voice counting down the frequency. At some point the tone will "warble" and the cartridge wobble visibly. This is the resonance frequency of the arm/cartridge.
If the resonance is too low - say 6 Hz as with a very compliant cartridge and a high mass arm the result is a cartridge very sensitive to footfalls and a sod to cue. On the other hand if the resonance is to high - say 20 Hz as with a low compliance MC cartridge and an ultra low mass arm the resonance will be audible and will colour the sound. Though this test does tend to spot when you've bought the wrong equipment it can also show the effects of changes in damping.

Yes, this is what LF resonance do to the main signal. You get stylus scrubbing when the cartridge stylus/cartridge swings at resonance. So for higher frequency tones you get speed stability problems/FM flutter, and if severe, audible warbling. This FM flutter around resonance could in theory also cause smearing of transients, higher noise and lower dynamics.

 

[Thomas_A]

big thanks to @Thomas_A for guiding me through looking at distortion of single tones over at the hoffman forum. i used my shure era v test record with trackability tests that use a combined signal of 200hz, 2.1k and 17k, filtered out each frequency and then looked at the distortion of each. comparing my v15vmr which has about 600 hours on it to a vm95ml with under 100, the distortion was similar at 200hz and 2.1k but there was a big difference between the two at 17k. i would have never thought to look at that before.

Thanks, a bit unaware which thread this was, but yes, complex signals can be more revealing for distortion.

 

[Quando]

Dla 0-20 Hz @Quando - po prostu sprawdź lead in groove przed tonem testowym 1 kHz lub ciszę między 1. a 2. przesunięciem. Przybliż niższe częstotliwości, a bardzo prawdopodobne jest, że zobaczysz szczyt gdzieś w okolicach 6-12 Hz.

A few questions
1. Will the peak amplitude of the unwanted resonance be better at 8 Hz, or at 12 Hz, or maybe at 6 Hz or at 18 Hz?
In which case will the amplitude be smaller? After all, the point is to keep the amplitude as small as possible.
2. How to measure this amplitude?

With a 1 kHz test signal, pink noise, white noise, or maybe a sweep of the entire band, or maybe some other signal, or maybe many test signals. Which measurement will give us a reliable result?
- What program should I use for the measurement?
- How to relate the level of the measured amplitude, to what level, so that it can be easily compared with another measurement?

You can also try to calculate, but there are so many unknowns here that such calculations are rather doomed to failure. Or maybe I'm wrong?

 

[morillon]

A few questions
1. Will the peak amplitude of the unwanted resonance be better at 8 Hz, or at 12 Hz, or maybe at 6 Hz or at 18 Hz?
In which case will the amplitude be smaller? After all, the point is to keep the amplitude as small as possible.
2. How to measure this amplitude?

With a 1 kHz test signal, pink noise, white noise, or maybe a sweep of the entire band, or maybe some other signal, or maybe many test signals. Which measurement will give us a reliable result?
- What program should I use for the measurement?
- How to relate the level of the measured amplitude, to what level, so that it can be easily compared with another measurement?

You can also try to calculate, but there are so many unknowns here that such calculations are rather doomed to failure. Or maybe I'm wrong?

you are well on your way to exploring this subject...
we will await with interest your feedback when you have "gone around" it....
(moreover, balle clorin has already pointed out a well-known test for a first "basic" approach , or less (two dedicated proposals..).. but you don't seem interested)
thank you

 

[melloncolliecat]

A few questions
1. Will the peak amplitude of the unwanted resonance be better at 8 Hz, or at 12 Hz, or maybe at 6 Hz or at 18 Hz?
In which case will the amplitude be smaller? After all, the point is to keep the amplitude as small as possible.
2. How to measure this amplitude?

With a 1 kHz test signal, pink noise, white noise, or maybe a sweep of the entire band, or maybe some other signal, or maybe many test signals. Which measurement will give us a reliable result?
- What program should I use for the measurement?
- How to relate the level of the measured amplitude, to what level, so that it can be easily compared with another measurement?

You can also try to calculate, but there are so many unknowns here that such calculations are rather doomed to failure. Or maybe I'm wrong?

1. You'll have to read up on it. But 9-11 Hz should be optimal. Down at 6, or even 7, the cartridge won't track as well. I haven't experienced anything higher than 11 or 12, so not sure what happens beyond that...
2. I answered this already. Just record a few seconds of silent groove, nothing more. You can include the 1Khz test signal if you want to "relate the level of the measured amplitude" to something. Anyway, then zoom in on maybe 0-25 Hz to get a good view, in whatever program you're using. You will see the peak. I find Audacity works fine for this, but the one you posted images from should work too, provided you can zoom in a bit.

If you want to see how the resonant peak changes, add maybe 5g of blu-tak on the headshell - and of course make sure to re-balance the arm and check the VTF again. Record some silent groove again. The resonant peak will have moved, but not by much.

 

[Quando]

1. You'll have to read up on it. But 9-11 Hz should be optimal. Down at 6, or even 7, the cartridge won't track as well. I haven't experienced anything higher than 11 or 12, so not sure what happens beyond that...

Currently, Audi Technica advertises such a set on its website. Let's assume that this is a set with the popular Technics 1200GR turntable, quick calculations in my head, suggest that the resonance peak here will be around 6 Hz.
After the end of the golden age of vinyl, Shure manufactured turntable cartridges that had a resonance peak of 14 Hz on the SME III tonearm. They believed that this was right.
Technics designed turntables so that the resonance peak was at 12 Hz.
You can read on the Internet, an article by an engineer from a company... I don't remember the name now, which performed measurements of turntable cartridges in the 70s and whose name appears on the measurement results attached to the cartridges.
Which engineer proved that the most desirable frequency of the resonance amplitude is around 15-18 Hz, and not as is commonly believed today, 8Hz-12 Hz
Shure Ortofon also had a lot to say on this subject. Denon etc. etc.
The creator of the program for measuring the frequency response of a phonograph cartridge claims that it doesn't matter anyway, because it has a small impact on the frequency response of the phonograph cartridge, it's hard to disagree with him.

What the fuck is going on here?

 

[Thomas_A]

There is lot written regarding the LF resonance. On a record the lateral inducer starts at 0.55 Hz and its overtones 1.1, 1.65. 2.2…. So lateral fundamental resonance can be quite low e.g. 6 Hz without giving too much problems. For the vertical inducer you have signals that are based on warp frequency; a record can be warped in many shapes, but the main peaks are usually said to be around 4-6 Hz. So the vertical fundamental resonance can and should be much higher, e.g. 20 Hz without problems. This is because LP music content is only laterally cut below 100-150 Hz.

In practice I have found that damped resonance gives the lowest risk for FM flutter around 4-20 Hz where our hearing is most sensitive to flutter. Flattening records is a way to address the problem at the source.

 

[Quando]

Can we agree that the amplitude of unwanted resonance in the range of 0-20 Hz should be as small as possible, regardless of the frequency at which this amplitude peaks?

 

[Thomas_A]

Can we agree that the amplitude of unwanted resonance in the range of 0-20 Hz should be as small as possible, regardless of the frequency at which this amplitude peaks?

It is generally beneficial yes. But frequency is also important to avoid the triggering LF frequencies of LPs.