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Objective measurements of phono cartridges

jhaider

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Carlo Lo Raso and Dr. David Rich have recently collaborated to develop protocols to measure phono cartridges. They're injecting the measurement signals from NOS test records, and analyzing the measurements using modern equipment.

They published their first review last month, of a Shure M97xE:
http://hometheaterhifi.com/reviews/vinyl/turntable-accessories/shure-m97xe-phono-cartridge-review/

Given the bent of this forum I thought this review and subsequent ones would be of interest here. This review is the first phono cartridge review I have seen that attempts to objectively characterize the cartridge's performance.

Disclosure: I sporadically write for SECRETS. Posted with moderator approval.
 

RayDunzl

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Is there such a device as this?

A little plate, with a dimple simulating the groove to accept the stylus, which vibrates on demand in two (maybe three if needed) axes with a range of frequencies to exercise a cartridge without using a vinyl test record?

Something like laying the stylus on the tip of an inverted cutting lathe head.
 

Cosmik

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Fascinating to see the lid lifted on the horrors, compromises and myriad decisions that have to be made in order to play vinyl!
 

Thomas savage

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Carlo Lo Raso and Dr. David Rich have recently collaborated to develop protocols to measure phono cartridges. They're injecting the measurement signals from NOS test records, and analyzing the measurements using modern equipment.

They published their first review last month, of a Shure M97xE:
http://hometheaterhifi.com/reviews/vinyl/turntable-accessories/shure-m97xe-phono-cartridge-review/

Given the bent of this forum I thought this review and subsequent ones would be of interest here. This review is the first phono cartridge review I have seen that attempts to objectively characterize the cartridge's performance.

Disclosure: I sporadically write for SECRETS. Posted with moderator approval.
Thanks for posting this :)
 

dallasjustice

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How many phono cartridge manufacturers measure their product/designs to this extent?

I think the high frequency roll off would sound pleasing to many folks. To me, LPs fall apart at low frequency.
 

Jakob1863

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Is there such a device as this?

A little plate, with a dimple simulating the groove to accept the stylus, which vibrates on demand in two (maybe three if needed) axes with a range of frequencies to exercise a cartridge without using a vinyl test record?

Something like laying the stylus on the tip of an inverted cutting lathe head.

Bruel & Kjaer did something like that back in the old days, using sort of a small "shaker" to vibrate the phono cartridge and measuring the output.
It worked - a big advantage was the exclusion of test record influence - but of course didn´t include the real world effects of a cartridge coupled to a rotating vinyl surface.
If there is interest i´ll look in our archive (fast search wasn´t successful).....
 

Frank Dernie

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This is interesting to me historically.
When I worked for Garrard in the mid 70s we always used the cartridge output (after RIAA correction) to evaluate the effectiveness of a record player design, our own and competitor's models, on the basis that was the combination of everything coming together and was the important bit - a bit like the analogue output of a DAC is the important thing to look at.
Record players are very interactive with their environment and their various components.
Cartridges are pretty poor in general and there are compromises to make them fairly universal.
They are seismic type transducers and the correct place for damping in such a transducer is between its mass (the body and arm) and the vibration source (the record surface) so the Shure with its damped brush is the only cartridge I know of which is technically "correct". Damping the cantilever suspension is a poor compromise for practicality.
Here is a list of things off the top of my head which may effect the analogue output.
Arm resonance.
Top plate resonance, and where the arm and bearing are mounted relative to it.
Bearing noise.
Motor noise.
Speed fluctuation.
Where and how the TT is supported.
Getting best performance is not necessarily expensive at the manufacturing stage, but is at the R&D stage. I remember the solution to a chassis resonant peak being seen in the output was to punch a ½" hole in the top plate, this cost pennies but the analysis and instrumentation required to find the solution was very, very expensive back then, relatively easy nowadays.

In the article there is reference to better cartridges on test. Is there any link to such tests? My experience is just the tests done by HiFi News which seems to be the only english language magazine testing cartridges.
 
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jhaider

jhaider

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In the article there is reference to better cartridges on test. Is there any link to such tests?

Those tests haven't been published yet. I don't have any information on their progress or publication date either, sorry.
 

Frank Dernie

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Really? I thought it was all rather well-known and obvious to people who play a decent amount of vinyl (e.g. me).
I tend to agree.
What I listen to is infinitely more influenced by whether I like it than whether the recordong quality is good.
Also, IME, the mastering quality and, probably, the recording engineer's expertise in chosing and positioning microphones has a bigger influence on the sound than the medium chosen to distribute it on, whether LP, CD or file based.
I have fabulous sounding and disappointing sounding recordings on any of these media which leads me to this conclusion.
Sure the whole LP process is riddled with compromise and innaccuracy, and it has amazed me since the mid 70s when I became aware of these shortcomings working in the business, that LPs sound as good as they do.
Once I found I could make a perfect copy of my LPs digitally I had a go at doing so but gave up after the first disc, far too tedious life is too short, so if the music I want to listen to is on an LP, I play it.
After all Bach over my phone sounds better than most pop music on the best system possible to my brain.
 

Cosmik

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Really? I thought it was all rather well-known and obvious to people who play a decent amount of vinyl (e.g. me).
The Shure M97xE’s measured frequency response shows that the upper end starts to gradually roll off from 4kHz on up. Left and right traces track fairly closely until about 10kHz....
...In 1998, when Shure moved phono cartridge production to a new smaller factory, the typical laminated cores used in good phono cartridges were replaced by a solid core....
...Note the imbalance above in the graph above 3000 Hz which may be a quality control issue...
...it is not just amplitude but also phase that changes with frequency in the crosstalk measurement.
...the large amount of pleasing 2nd harmonic distortion
...Spurs at 120Hz and 360Hz are from power line hum getting into the cartridge.
...A few claim that this pink noise floor may contribute to the LP – CD debate. The added noise is conjectured somehow to be perceived as subjectively pleasing
...his graph shows measured channel separation at 5kHz to be 19 dB. Note the noise floor on the right (silent side) is lower than the modulated left channel.
...With the stabilizer brush up, the resonance is at 7.5Hz. The Q is calculated from the amplitude at resonance and the two frequencies -3dB down on the sides of the resonance. The higher the Q the more energy storage in the system. With the brush up, the resonance is at 7.5Hz and the Q was calculated to have a value of 4. The Q is likely higher than this and the FFT is limiting the resolution. More on Q calculation in an upcoming article, “How We Test Cartridges”, coming soon to the website.
With the brush down the amplitude of the resonance drops by 18dB. The Q has reduced to 1.4 indicating much less energy storage in the arm / stylus mechanical system.
High compliance is important for distortion performance when stylus displacements are high, especially at low tracking forces, but the trade is a low resonance frequency and high energy storage Q. The Shure brush solves this tradeoff.
...In general, it appears mis-tracking is defined to be audible distortion. On single tones that is around 5%. As will be seen below these numbers appear to be optimistic especially the 10kHz number.
...This graph shows the Shure M97xE having a THD of 1.5% at 1kHz.
...Stylus shape and tip mass play an important role in distortion tests. The Shure 0.2 x 0.7 mil stylus is thinner than others at this price range. The Shure has bonded stylus, common at this price point, which adds mass relative to nude mounting found in cartridges a little under twice this price.
...Those types of cartridges have a Micro Ridge stylus and low mass cantilevers made with materials such as beryllium or boron. The Shure V15 5MR and a long line of Audio Technica cartridges from the 80s to today had these ingredients along with high compliance. Audio Technica had no brush and the cartridges they produced had low frequency resonances with huge energy storage. You needed an external damping device added to the arm. Audio Technica has lowered the compliance in the latest cartridges which giveth and taketh away.
etc. etc. etc.
And you can tell all that just by listening. I'm impressed! :)
 

watchnerd

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And you can tell all that just by listening. I'm impressed! :)

Oh I didn't say I could tell by listening.

But if one reads articles on cartridge design, or interviews with some of the cart manufacturers who are honest about their engineering challengers (Soundsmith, Nagaoka), it's all been documented and discussed before.

Lastly, if you due a truly instrumented cart install using a Fosgometer or oscilloscope, this stuff shows up, too.
 

svart-hvitt

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Cosmik

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Simply amazing! From 1976. Over 40 years old. The quality of the charts, the design and layout of the article before modern digital time.

It seems like modern day man is hardly able to exploit all of today’s fancy tools.
Although there is the small matter of modern man inventing digital audio in order to comprehensively fix any and all the technical issues mentioned in the paper! It is only hobbyists and eccentrics who would need to read that document at all :)
 

Frank Dernie

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watchnerd

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Although there is the small matter of modern man inventing digital audio in order to comprehensively fix any and all the technical issues mentioned in the paper! It is only hobbyists and eccentrics who would need to read that document at all :)

We need a fancy name for the hobbyists / eccentrics.

In the watch collecting world, the collectors of mechanical timepieces like to refer to themselves as 'horologists'.
 
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