MM vs MI vs MC

[dlaloum]

Have you got any evidence of these ultra-low-mass-cantilever carts having a FR that doesn’t vary (much) with signal complexity?

For those who are heavily physics oriented - there are many articles written about scanning force microscopy - which is basically very very similar to Vinyl replay - they use a cantilever with a needle on the end of it to "feel" individual atoms - their problems and the associated maths is pretty much the same as for cartridge styli/cantilevers...

2.1.6 Effective mass and eigenfrequency of the cantilever

www.ntmdt-si.com

Here is the key point about cantilever resonance:
"The cantilever eigenfrequency must be as high as possible, otherwise its natural oscillations will be readily excited due to the probe trace-retrace move during scanning or due to external vibrations influence."

Same deal for vinyl - for best results you need to move the eigenfrequency out, way above the audible frequencies, so its inevitable excitation will not affect what we are listening to.

P.S. I am no physicist... (beyond 1st year Uni physics...) - just a geeky layman.... but this was pointed out to me by a physicist audiophile - and measurements of many cartridges especially some of the very best ones of the 80's - seem to confirm this
Cartridges that achieve both an extended high end, and a flat high end frequency response, tend to be very low effective mass - and measurements seem to indicate resonant frequencies above 30kHz

 

[EJ3]

As was mentioned, running the record at a different speed should expose defects in the pressing. I had been experimenting with that prior, but I have to deal with using a phono preamp that applies RIAA.

Or we could...just listen to some music. I don't know.

Many Technics TT's can have their speeds easily changed:

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They also +-X percent of speed adjustment which can also be modified for more range of adjustment.

 

[levimax]

Thanks, the reason I ask is because I understand that a sweep tone test is too easy and gives an unrealistically good FR. Music is more wideband.

A wideband tone FR will give an FR measurement more representative of complex music with numerous instruments playing together.

Unfortunately they are not all that similar, eg

View attachment 193242
View attachment 193244

The top is the spot frequency FR, which would be much like a sweep tone FR, and the bottom is a wideband tone FR of the same cartridge (Rega Exact).

It would be easy to get cocky about the flat response of cartridges using the sweep tone, when in fact they are not doing so well at all with music.

The really ugly reality, that the discrepancy between the above two graphs tells us, is that the FR of a cartridge is chaotically jumping up and down as the music varies from simpler to more complex. Ugh!

cheers

Isn't the FR discrepancy you are proposing (i.e. FR changes with complex music) just IM distortion which can also be derived from the sweeps Harmonic distortion measurements? I don't see this being unique to LP playback.

I am not a "pink noise" expert but it seems to me that with all the possible harmonic distortion/ IM distortion sources involved with creating a pink noise test record and all the chances for constructive and destructive interference it would be extremely difficult to get it right and it would be very sensitive to different playback set ups.

Hopefully an expert can let me know if I am thinking about this correctly.

 

[JP]

@JP don’t appreciate cryptic comments like that, just say what you mean please.

I’m not saying PN is superior or has no problems of its own, I am saying that cartridge FR varies with simple vs complex test signals. And that is a real problem for music reproduction. A very real measure of how good a cartridge is would be how good it is at not changing FR with signal complexity.

Sometimes the journey is worth more than the destination. It's also unreasonable to ask someone to summarize pages of directly relevant discourse for you. What I linked to was the beginning of some of the most recent and relevant discussion on the matter, though most of the thread is a useful read for those genuinely interested.

The really ugly reality, that the discrepancy between the above two graphs tells us, is that the FR of a cartridge is chaotically jumping up and down as the music varies from simpler to more complex. Ugh!

These two graphs don't tell us anything. On one hand we've spots of unknown frequencies, from an unknown test record, with unknown smoothing. On the other is pink noise from an unknown test record, also with unknown smoothing. From this we can conclude ugly realities, or any reality at all?

 

[Newman]

They tell me something. Like you say, they are not proof due to lack of full knowledge. But the owner of the test lab has noted that the reason for the difference is not related to your queries, but occurs because the PN test signal is so much more difficult for a cart to handle. Until proven otherwise, IMO it's significant that he says so. It seems to be a fact that the FR curve of a cart varies with signal complexity.

PS I am rather destination focused, so cryptic links to huge threads of unknown quality and zero relevance at the point of linked entry are about as unhelpful as you can get. Following my request for clarity with 2c of pop psychology only reinforces the bad impression you are making.

 

[JP]

They tell me something. Like you say, they are not proof due to lack of full knowledge. But the owner of the test lab has noted that the reason for the difference is not related to your queries, but occurs because the PN test signal is so much more difficult for a cart to handle. Until proven otherwise, IMO it's significant that he says so. It seems to be a fact that the FR curve of a cart varies with signal complexity.

Appeal to authority, and until/unless substantiated it’s mere hand waving. This space is riddled with loose logic to explain away inconvenient measurement inconsistencies. Never mind that the plot has the signature of a known poor pink noise track. The concept isn’t without merit, but the ”evidence“ offered thus far is.

PS I am rather destination focused, so cryptic links to huge threads of unknown quality and zero relevance at the point of linked entry are about as unhelpful as you can get. Following my request for clarity with 2c of pop psychology only reinforces the bad impression you are making.

I‘d think a post about the quality of pink noise tracks from one of the foremost minds in analog, mixed-signal, and metrology would set the stage. There was no psychology offered in my response.

 

[dlaloum]

Yes a pink noise spectrum will have overlaid on the pink noise, the IMD and THD... across the entire frequency spectrum - and yes all simultaneous is harder than spot / sweep signals - there will be more distortion and it is harder for the needle to track the groove....

The sweep (or multiple point measurements) - are a more effective way of measuring specific behaviours, as they reduce the other variables impact - less IMD, less THD - and an FR where the reduced distortions result in a more "focused" FR.

It can however be argued, that a PN FR provides a more accurate reflection of what the cartridge will "sound like" when playing actual music... because music is complex and multi frequency - and does have the various forms of distortion overlaid...

You could potentially subtract the measured 2D & 3D distortions measured by a sweep, from the results of a PN test.... IMD would still be there of course - but the FR chart would be slightly more correct.... not sure how much of an impact it would have though.

 

[levimax]

Yes a pink noise spectrum will have overlaid on the pink noise, the IMD and THD... across the entire frequency spectrum - and yes all simultaneous is harder than spot / sweep signals - there will be more distortion and it is harder for the needle to track the groove....

The sweep (or multiple point measurements) - are a more effective way of measuring specific behaviours, as they reduce the other variables impact - less IMD, less THD - and an FR where the reduced distortions result in a more "focused" FR.

It can however be argued, that a PN FR provides a more accurate reflection of what the cartridge will "sound like" when playing actual music... because music is complex and multi frequency - and does have the various forms of distortion overlaid...

You could potentially subtract the measured 2D & 3D distortions measured by a sweep, from the results of a PN test.... IMD would still be there of course - but the FR chart would be slightly more correct.... not sure how much of an impact it would have though.

I wasn't just thinking about playback but also of actually trying to "record" PN to a record. It seems like the cutting head and it's interaction with the acetate would have distortion products that would make it difficult to cut a PN track accurately.

 

[dlaloum]

I wasn't just thinking about playback but also of actually trying to "record" PN to a record. It seems like the cutting head and it's interaction with the acetate would have distortion products that would make it difficult to cut a PN track accurately.

Ideally you would want to master it on the lathe at half speed - but I don't think any of the half speed lathes have survived... (weren't they the ones made by Ortofon?)

Given the amount of research that went into Vinyl in the 60's & 70's - I would be very surprised if this had not been tackled....

On the other hand, finding those documents, can be a challenge.

 

[Holmz]

…- the Dynavector cartridges with the ultra short cantilevers - under 3mm (some models under 2mm).
…

At any given displacement l/r or up and down, then they would seem like they would have more angular motion.
Whether that affects distortion or not, who knows.

 

[JP]

Ideally you would want to master it on the lathe at half speed - but I don't think any of the half speed lathes have survived... (weren't they the ones made by Ortofon?)

Given the amount of research that went into Vinyl in the 60's & 70's - I would be very surprised if this had not been tackled....

On the other hand, finding those documents, can be a challenge.

There are a good number of Neumanns with SP-02 motors that can turn the platter at half speed. The required EQ changes are a different matter.

The Adjust+ LP was reported to have accurate pink noise to 2k and Fieckert reported there were several cutting attempts to do that. The only one that didn’t show material errors to 20k was CH Precision.

 

[USER]

As I don't have a mythical, perfect pink noise test LP and only the working class CBS record, this will have to do: Stanton 681EEE MKIII. Obviously, tracking ability doesn't show up here so use your better judgement with regards to known stylus type and quality. Hey, at least you can compare these results to each other!

I'm a bit surprised by this result. Could stylus wear be the culprit and would high frequency drop-off be this smooth?

Audio Technica AT7V coming next week!

 

[JP]

Seems to jibe: https://worldradiohistory.com/hd2/I.../HiFi-Stereo-Review-1975-05-OCR-Page-0044.pdf

 

[Digital1955]

Is the Clearaudio CA-TR-1007 as good as the original JVC TR-1007? Anybody have a comparison of the CA-TR-1007 to the JVC TR-1007 and/or CBS STR-100? @JP ? You seem to have the penchant for test records.

 

[Holmz]

Is there a test record with a groove but with no music in that groove?
Like for evaluation of external vibration control, etc?

 

[levimax]

Is there a test record with a groove but with no music in that groove?
Like for evaluation of external vibration control, etc?

I have the Ultimate Test LP which has a silent track... there are probably others...not sure I can recomend this record though...no sweeps, just spot tones and mine is off center and warped since new

 

[dlaloum]

Depends on the vibrations you are looking to control - if they are external to the TT - ie: footfalls, music/sounds in the room etc...

Then you can on many TT's, simply keep the TT turned off, and gently place the needle on the platter matt - use the cartridge to "read" the vibrations in the platter - without the platter turning.

The fly in the ointment, is that many automatics and semi-automatics isolate the signal path when the TT is off, or the needle isn't on the record (which avoids pops as you cue up the record) - Manuals typically don't have this problem.

On the other hand, you can use a Smartphone as an accelerometer/sensor, rather than using the cartridge....

 

[JP]

Is the Clearaudio CA-TR-1007 as good as the original JVC TR-1007? Anybody have a comparison of the CA-TR-1007 to the JVC TR-1007 and/or CBS STR-100? @JP ? You seem to have the penchant for test records.

That one I don’t have.

 

[Holmz]

Depends on the vibrations you are looking to control - if they are external to the TT - ie: footfalls, music/sounds in the room etc...

Then you can on many TT's, simply keep the TT turned off, and gently place the needle on the platter matt - use the cartridge to "read" the vibrations in the platter - without the platter turning.

The fly in the ointment, is that many automatics and semi-automatics isolate the signal path when the TT is off, or the needle isn't on the record (which avoids pops as you cue up the record) - Manuals typically don't have this problem.

On the other hand, you can use a Smartphone as an accelerometer/sensor, rather than using the cartridge....

Yeah the example I gave was… an example.
I really want to evaluate noise in the track before and after cleaning the LP.

But your approach is nice to know for vibration… Well done there!

 

[Digital1955]

That one I don’t have.

Ok, I found out it's currently available. I was trying to determine if its worth 80$