Phono Cartridge Response Measurement Script

[morillon]

How i that 24 vits possible when the noise floor is -60db typically

just that it requires otherwise a lot of effort to target the maximum-peak.. it just helps a little by giving itself "more margin than reason" ;-)

 

[Bob from Florida]

How i that 24 vits possible when the noise floor is -60db typically

Use compression during the recording process to move your minimum signal above the noise floor. Above minus 60 db in your example. Still gives you 36 db dynamic range at 16 bit’s resolution and 84 db dynamic range at 24 bit’s. Plenty of range with either resolution for virtually any recording in existence. Was that what you were asking for?

 

[Balle Clorin]

Typical Groove Noise is -60db , the highest level before mistracking is maybe +18 so peak signal to noise level is 78 say 80db SNR at best. So what is the point of 24 bits 144db range, 16 bits and 96db is more than enough , or what am I misunderstanding?

Adding 20db for RIAA maybe, still 96db/16 bits should be enough, or?

 

[MaxwellsEq]

Typical Groove Noise is -60db , the highest level before mistracking is maybe +18 so peak signal to noise level is 78 say 80db SNR at best. So what is the point of 24 bits 144db range, 16 bits and 96db is more than enough , or what am I misunderstanding?

Adding 20db for RIAA maybe, still 96db/16 bits should be enough, or?

You are absolutely correct. LP does not need more than 16 bits.

When using a fixed bit ADC the worst possible thing you can ever do is overload its input. So given splats, clicks etc. it makes sense to have considerably more headroom, just in case. Once captured, after cleaning worst clicks and then using normalization, downscaling to 16 bits makes good sense.

 

[JP]

Not if the ADC recovers fast. The data is already lost.

 

[JP]

Updated second post to reflect that the script code is now located at https://sjplot.com. Issues that require code changes should also be reported there.

 

[Quando]

.
I don't know if I'll ever figure out how to measure it It's terribly complicated. Maybe
I'm interested, however, in why this method doesn't also cover frequencies below 20 Hz? This is important because in the range up to 20 Hz there is always an amplitude of unwanted resonance. Which, I think, affects some range of the entire 20Hz-20 kHz band.

 

[melloncolliecat]

Well, for one thing, below 20Hz things are highly tonearm, and to some extent, turntable dependant.

 

[JP]

.
I don't know if I'll ever figure out how to measure it It's terribly complicated. Maybe
I'm interested, however, in why this method doesn't also cover frequencies below 20 Hz? This is important because in the range up to 20 Hz there is always an amplitude of unwanted resonance. Which, I think, affects some range of the entire 20Hz-20 kHz band.

As the tool is designed for the measurement of cartridge response, some care was taken to make it as immune to such effects as reasonable. If someone wants to measure fres, they should use an appropriate tool.

 

[Quando]

As the tool is designed for the measurement of cartridge response, some care was taken to make it as immune to such effects as reasonable. If someone wants to measure fres, they should use an appropriate tool.

Does the amplitude level of the resonance affect the result of these measurements, or does it not affect it because it is somehow filtered out?
I simply want to measure how the frequency response of the cartridge, crosstalk, looks like, depending on the amplitude level of the unwanted resonance.

 

[narud]

Does the amplitude level of the resonance affect the result of these measurements, or does it not affect it because it is somehow filtered out?
I simply want to measure how the frequency response of the cartridge, crosstalk, looks like, depending on the amplitude level of the unwanted resonance.

i think @USER measured a cart on both a heavy arm sony and a denon servo arm table and a difference showed up in the low end of the spectum but the highs were the same? or this could be a false memory.

 

[dlaloum]

.
I don't know if I'll ever figure out how to measure it It's terribly complicated. Maybe
I'm interested, however, in why this method doesn't also cover frequencies below 20 Hz? This is important because in the range up to 20 Hz there is always an amplitude of unwanted resonance. Which, I think, affects some range of the entire 20Hz-20 kHz band.

It depends on what you seek to analyse - below 20Hz there will be the tonearm resonance which will dominate... recording the low frequencies is very useful in tuning arm/cartridge mass and damping (if you have adjustable damping on your tonearm) ... but it will tell you very little about the cartridge.

You might need the low frequencies if you were seeking to look into the compliance and damping of the cantilever suspension... which really is the same set of issues as the tonearm one...

 

[Quando]

It depends on what you seek to analyse - below 20Hz there will be the tonearm resonance which will dominate... recording the low frequencies is very useful in tuning arm/cartridge mass and damping (if you have adjustable damping on your tonearm) ... but it will tell you very little about the cartridge.

You might need the low frequencies if you were seeking to look into the compliance and damping of the cantilever suspension... which really is the same set of issues as the tonearm one...

I am interested in the behavior of a given cartridge with a turntable. If I increase or decrease the effective mass, or use a damping system, or do not use a damping system, change the tonearm, or change the entire turntable, what effect will this have on the frequency response of the turntable cartridge.
It is known that the same cartridge on one tonearm, or turntable, plays one way, and on another turntable and tonearm, plays differently.
Analyzing the behavior of the cartridge itself, in isolation, or even deliberately making the measurement result independent of the turntable, is useless.

 

[Balle Clorin]

What I do this :
For cartridge response and effect of resonanc /compliance effective mass tonearm compatibility 20-20kz.
- Run CA TRS-1007 and the frequency script.
- run a WOW and flutter or 1khz , analyse file FFT in CoolEditPro or REW and look for for side bands irregularities.
- look at the wav file vs time and hope for even plot, bumps of wavy plot mean resonances . One problem is that test records have inherent irregularities and sidebands too, so you need to try several records on several records to find the best , if my memory serves me right the best single tone record for this is Japanese test vintage records, ala Denon, Toshiba, wow flutter and resonance shows up as side bands around the tone, if the TT speed stability is not very good the side bands will be blurred and obscured.

ARM/CART resonance
- Run Denon 4-100hz test record sweep.
- Run test record with moth vertical and lateral resonance tracks ( old Ortofon test record or B&K QR test record have that )
Plot in appropriate program , REW or other anything but Audacity which I thinkbplot horrible. I cannot figure it out .
-There is one other program that I do not recall the name of , the one Archimagio site use in his measurements , it gives high resolution plots for low frequency.EDIT: Rightmark is the program.

 

[Quando]

EDIT: Rightmark is the program.

This program is so old that I forgot about it (2005)

Yes, everything is more visible here.

From what I can see here, increasing the effective mass reduced the amplitude level of the unwanted resonance, but it has no effect impact on the 20Hz-20kHz band, in this range the graph seems to be the same

I have to play with other test signals.....

 

[Quando]

10kHz-20kHz

 

[Balle Clorin]

Not sure what you are comparing ?. Is L and R different mass? Which test record?

If you import the files til REW you can subtract one from the other to show the difference only. Trace arithmetic and take magnitude A/B

 

[Quando]

Hi Fi News Record Side B track 7, sweep 20Hz-20kHz
Ortofon Concorde 20 (first version), different effective mass, other parameters the same.
I can't show the difference between measurements in REV.
How do I do it?

Concorde_20_przeciwwaga_Technics.wav

drive.google.com

Concorde_20_przeciwwaga_Ortofon.wav

drive.google.com

 

[dlaloum]

I am interested in the behavior of a given cartridge with a turntable. If I increase or decrease the effective mass, or use a damping system, or do not use a damping system, change the tonearm, or change the entire turntable, what effect will this have on the frequency response of the turntable cartridge.
It is known that the same cartridge on one tonearm, or turntable, plays one way, and on another turntable and tonearm, plays differently.
Analyzing the behavior of the cartridge itself, in isolation, or even deliberately making the measurement result independent of the turntable, is useless.

Sure - but it is best done as a seperate measurement...

You can use a wideband measurement for multiple purposes - but normally this is avoided, as tracking misbehaviour can be triggered by a misadjusted arm/cartridge combo - as the low frequency trigers large movements, that then cause the needle to mistrack the high frequencies.... making the whole measurement a mess!

Best to do the low frequency test seperately from the frequency response.

This is also why most recordings on LP's tend to be frequency limited even above 20Hz... keeping away from the danger zone.... often starting to get signal up at 30 or 40Hz...

If you have a cartridge / arm setup properly dialed in, the resonance should be down around 10Hz, and damped ... which minimises unwanted motion of the arm, and the harmonics of the resonance frequency...

I love the electro damped arms from JVC, Denon and Sony... also the Magnetically damped Dynavector, or the many arms with various oil damping schemes... (including the KAB trough for Technics Sl1200mk2 and near relatives...) - but the electro damped models allow for very easy and quick experimentation and adjustment with no mess...

 

[Quando]

Sure - but it is best done as a seperate measurement...

You can use a wideband measurement for multiple purposes - but normally this is avoided, as tracking misbehaviour can be triggered by a misadjusted arm/cartridge combo - as the low frequency trigers large movements, that then cause the needle to mistrack the high frequencies.... making the whole measurement a mess!

Best to do the low frequency test seperately from the frequency response.

This is also why most recordings on LP's tend to be frequency limited even above 20Hz... keeping away from the danger zone.... often starting to get signal up at 30 or 40Hz...

If you have a cartridge / arm setup properly dialed in, the resonance should be down around 10Hz, and damped ... which minimises unwanted motion of the arm, and the harmonics of the resonance frequency...

I love the electro damped arms from JVC, Denon and Sony... also the Magnetically damped Dynavector, or the many arms with various oil damping schemes... (including the KAB trough for Technics Sl1200mk2 and near relatives...) - but the electro damped models allow for very easy and quick experimentation and adjustment with no mess...

This is what I want to measure: if I shift the resonance peak from a frequency of 10 Hz to 7 Hz, because I increase the effective mass of the arm by about 15 grams, or shift the peak from 7 Hz to 10 Hz, because I decrease or reduce the effective mass (different arms), how will the frequency response of the turntable cartridge change, or maybe it will not change?