Thank you George. However, only the 1st 10 of those links work and I've tried a number of ways.......
If the links are down, would you please re-up them ?
thx
LD
Thanks Ricardo. This is what I wanted to know.
Now, here is the flat playback of the full range frequency sweep track (Side 2 Band 7) from the HFN002 Test LP.
24bit/96KHz recording, 18s 577.021ms, 1783394 samples
With Stanton MKVB5
https://www.dropbox.com/s/05tc4u2qbkvkf5p/HFN%20S2%20B7-Stanton_MKVD5%20flat.wav?dl=0
With Shure_M97xE
https://www.dropbox.com/s/26bw991oo31a1yp/HFN%20S2%20B7-Shure_M97%20flat.wav?dl=0
The same Shure_M97xE recording but manually declicked
https://www.dropbox.com/s/m0ska9lqnjaqu93/HFN%20S2%20B7-Shure_M97%20flat-declicked.wav?dl=0
Cartridge on tonearm of Kenwood KD-3100
L coil connected in parallel to 47KOhm to the - input of the flat AD620 preamplifier (in single mod, x53 gain). Output to L Input of MAudio card.
Work your way to see the wave envelope and do the FFT as you see best. Please inform me of what you get
George
Yes. Thanks. Something went wrong.
I put down the old 11 to 18 files and uploaded them again.
I checked and they work .
11th 7.5minutes
https://www.dropbox.com/s/yqcdksu1o8x4rob/11th%207-5minutes.wav?dl=0
12th 15minutes
https://www.dropbox.com/s/nj0ee28q9c6ha89/12th%2015minutes.wav?dl=0
13th 30minutes
https://www.dropbox.com/s/t63mwb4qtyiidv3/13th%2030minutes.wav?dl=0
14th 1hour
https://www.dropbox.com/s/2l5eo9r77u3qid0/14th%201hour.wav?dl=0
15th 2hours
https://www.dropbox.com/s/7y8yyniui705xci/15th%202hours.wav?dl=0
16th 4hours
https://www.dropbox.com/s/zty9zgcaimvqayn/16th%204hours.wav?dl=0
17th 8hours
https://www.dropbox.com/s/pn2s0sgpntheco2/17th%208hours.wav?dl=0
18th 16hours
https://www.dropbox.com/s/sicagga5k091rkv/18th%2016hours.wav?dl=0
For two days 🙂
George
George I'm doing some ground lamb kebabs with tzatziki tomorrow (local farm lamb), I find recipes that are mild and some loaded with middle eastern spices what is the most common in Greece?
It depends on where one lives.
If the place has inherited the tradition of Asia Minor brought by the population that lived there and was forced to move the years after 1922, then there the kebab is loaded with a lot of oriental spices (Smyrna style kebab)
For a first try, this one is quite balanced
Adana Kebabs (Ground Lamb Kebabs) Recipe | Serious Eats
Enjoy the experience with a good company (the plain brutal version of ars longa, vita brevis 😀)
George
If the place has inherited the tradition of Asia Minor brought by the population that lived there and was forced to move the years after 1922, then there the kebab is loaded with a lot of oriental spices (Smyrna style kebab)
For a first try, this one is quite balanced
Adana Kebabs (Ground Lamb Kebabs) Recipe | Serious Eats
Enjoy the experience with a good company (the plain brutal version of ars longa, vita brevis 😀)
George
Enjoy the experience with a good company (the plain brutal version of ars longa, vita brevis 😀)
George
Thanks that's most important, my daughters spice collection got lost in our move, the Urfa pepper and sumac will have to have a substitute but the mix resting in the fridge smells very fine.
Lucky, on my reading Happ’s paper covers off quite a few matters with which you appear to take issue.
The Happ-Shure model shows the interplay of all the elements. Cantilever flex is there and suspension flex and vinyl flex and all are necessary to explain the observed behaviour of the cartridge. The boundary conditions do merely modify the resonance – they are the essential conditions required to determine the modelled and observed flexure and resonances.
The first step in building any model like the Happ-Shure model is to see how closely its output matches the lumped parameter model – what you characterise as the rigid body and spring model. As my supervisor Professor Traill-Nash put it 1981, “If your more sophisticated FORTRAN model of damped beam flexure doesn’t give a first resonant frequency within about 20% of both the measured figure and the estimate of the second-order Bernoulli-Euler lumped parameter model, then it’s wrong and you’re back to the drawing board!”
While Happ doesn’t provide values, he provides a good deal of information about boundary conditions from the introductory paragraphs onward:
On pages 4 to 6, Happ shows the development of a simple model without damping. His conclusion was:
He goes on to include translational and rotational damping in the more sophisticated model that produced the charts:
Actually, the model shown in Figure 8 of Happ's paper (the same as Figure 5 in the Shure online technical seminar) allows both ends to translate and to rotate. And Happ clearly provides for elasticity and damping to be included for every translating and rotating element - see the quote above.
To get to realistic results, spring-like elastic deformation IS included in the both the simple Happ-Shure model and the more complex model that produced the lovely charts. And there are good reasons to do so:
1). Vinyl esters exhibit elastic deformation – this is known and is easily accounted for, whether we are deciding how deep to bury a PVC stormwater pipe under a road, or modelling a stylus in a groove.
2). Beyond a certain stress, the deformation becomes plastic: we know that the pipe bends and doesn’t spring back; we have seen photo-micrographs of smeared scars on the groove. We want to design to avoid both and we have the data to do so.
3). Skating, surfing, skin effects and all manner of things may ALSO occur, though I’ve not seen a description or measurement of these phenomena for vinyl esters.
The Happ-Shure model shows the interplay of all the elements. Cantilever flex is there and suspension flex and vinyl flex and all are necessary to explain the observed behaviour of the cartridge. The boundary conditions do merely modify the resonance – they are the essential conditions required to determine the modelled and observed flexure and resonances.
The first step in building any model like the Happ-Shure model is to see how closely its output matches the lumped parameter model – what you characterise as the rigid body and spring model. As my supervisor Professor Traill-Nash put it 1981, “If your more sophisticated FORTRAN model of damped beam flexure doesn’t give a first resonant frequency within about 20% of both the measured figure and the estimate of the second-order Bernoulli-Euler lumped parameter model, then it’s wrong and you’re back to the drawing board!”
While Happ doesn’t provide values, he provides a good deal of information about boundary conditions from the introductory paragraphs onward:
The boundary conditions for this analysis were progressively improved to obtain a realistic generalized model. Initially the tip end of the shank was represented by a mass and a spring used to represent the interaction with the record material. A transducer element with elastic bearing represented the other end. The present model includes damping in conjunction with each boundary condition and allows for changes in compliance and damping at each frequency. (page 3)
On pages 4 to 6, Happ shows the development of a simple model without damping. His conclusion was:
The results of the first system modeled were encouraging but revealed the weakness of not including damping in the model. The frequency response showed several resonances in frequency ranges which seemed reasonable; however, the shape of the curve was unrealistic due to the infinite Q of each resonance. (page 6)
He goes on to include translational and rotational damping in the more sophisticated model that produced the charts:
It is assumed that internal damping in the stylus shank is negligible and that the entire damping which occurs is due to the elastic bearing and record. It was found that both rotational and translational damping was required to realistically represent the stylus mechanical system. Thus dampers were paralleled with each spring element in the system. (page 6)
Actually, the model shown in Figure 8 of Happ's paper (the same as Figure 5 in the Shure online technical seminar) allows both ends to translate and to rotate. And Happ clearly provides for elasticity and damping to be included for every translating and rotating element - see the quote above.
To get to realistic results, spring-like elastic deformation IS included in the both the simple Happ-Shure model and the more complex model that produced the lovely charts. And there are good reasons to do so:
1). Vinyl esters exhibit elastic deformation – this is known and is easily accounted for, whether we are deciding how deep to bury a PVC stormwater pipe under a road, or modelling a stylus in a groove.
2). Beyond a certain stress, the deformation becomes plastic: we know that the pipe bends and doesn’t spring back; we have seen photo-micrographs of smeared scars on the groove. We want to design to avoid both and we have the data to do so.
3). Skating, surfing, skin effects and all manner of things may ALSO occur, though I’ve not seen a description or measurement of these phenomena for vinyl esters.
Thank you for an interesting post, Bondini.
I more take issue with the matter of careful interpretation of exactly what the author said, and parameters necessary to make the model work, which aren't disclosed. Just because the model supports nominal elastic/damping deformation of vinyl, doesn't mean the parameters are significant in the scheme of things, ie that it happens to any meaningful extent.
Yes. But strictly we don't know the boundary conditions used to obtain realistic results, because the author didn't disclose them. So can't know the relative contributions and importance. For all we know, the vinyl end mostly contributes rotational damping: we can't say. However, we might say from the narrative and discussion that the primary vibrating element involves cantilever flex modes, modified by boundary conditions, and we might suppose that all were necessary.
Well, I disagree: IMO the author tells us very little about boundary conditions, other than implying that a spring/mass model is inappropriate for the tip end, that damping is necessary, and that frequency dependant compliance is necessary. But not at which end, and what narrative there is concerns itself with properties of the suspension bung end, but is silent about the vinyl tip end. I think it's reasonable that the bung end has the influence, IMO, in the sense it probably provides most damping and scope for translational yield.
Yes. But that does not tell us the relative contribution to damping from each of the suspension bung and tip ends.......
But that doesn't mean that both the pivot bearings need to translate to any significant extent to make the model work, though obviously the bung end must in practice. It comes back to specific parameters, which strictly we don't know........
In the model yes, but we don't know the parameters so can't say whether deformation occurs in the model to any meaningful extent.
I agree with what you say about static elastic deformation of vinyl, with good reason. Though for equally good dynamic reasons, IMO, it's unlikely to apply in vinyl playback to any meaningful extent.
Historically, I think the Happ paper was properly read as embracing all the elements of cantilever, suspension bung, and vinyl tip behaviour. Which it does. But I also think the paper can be interpreted as 'all things to all men', in the sense that it has been taken to endorse whatever common knowledge might prevail as to dominant effects. The absence of values for parameters has fuelled this, IMO. Careful scrutiny means that the paper doesn't help quantify the matter of vinyl deformation, for example. However one might read it as indicating, even if small or near zero, a boundary condition modifier of cantilever flex.
LD
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I would not totally discount the stiffness and damping loss at the groove-tip interface. Wouldn't the relative importance of stylus groove springiness and cantilever flexure depend on specific engineering design? As more delicate pickup designs evolve to lower tracking force the relative importance of the former decreases and that of the latter increases.
In formulating my FORTRAN model I applied the experimental results of James V. White in his paper "An Experimental Study of Groove Deformation in Phonograph Records" (J.AES 18,5, Oct 1970, pp.497-506) which was based on his Ph.D. dissertation at Harvard University.
Abstract: "Groove deformation has been analyzed in the literature primarily in terms of classical elasticity theory, which is based on assumptions that are not appropriate for stylus-groove contact. To determine the actual deformation-force relations, complex groove impedances have been measured as a function of tracking force, groove speed, etc. The results obtained are contrasted with classical predictions."
White used custom vinyl pressings to determine the complex mechanical groove impedance presented to the playback stylus as a function of tracking force, groove speed, etc.
A few of White's conclusions that are perhaps pertinent to the current discussion are: (1) "Hertzian theory incorrectly describes the groove deformation even when tracking force is small enough to preclude macroscopic plastic deformation. The grooves were softer at small tracking forces, and harder at high tracking forces than Hertz's theory predicts." White cites numerous reasons explaining why Hertz's theory does not apply to phonographs. (2) "Experimental results ... at 6.32 kHz with a 0.7 mil stylus showed that losses were small at audio frequencies and that the resistance function was inversely proportional to the groove velocity in the range from 0.30 to 0.45 m/s. The hardness function, on the other hand, was independent of the groove velocity."
In formulating my FORTRAN model I applied the experimental results of James V. White in his paper "An Experimental Study of Groove Deformation in Phonograph Records" (J.AES 18,5, Oct 1970, pp.497-506) which was based on his Ph.D. dissertation at Harvard University.
Abstract: "Groove deformation has been analyzed in the literature primarily in terms of classical elasticity theory, which is based on assumptions that are not appropriate for stylus-groove contact. To determine the actual deformation-force relations, complex groove impedances have been measured as a function of tracking force, groove speed, etc. The results obtained are contrasted with classical predictions."
White used custom vinyl pressings to determine the complex mechanical groove impedance presented to the playback stylus as a function of tracking force, groove speed, etc.
A few of White's conclusions that are perhaps pertinent to the current discussion are: (1) "Hertzian theory incorrectly describes the groove deformation even when tracking force is small enough to preclude macroscopic plastic deformation. The grooves were softer at small tracking forces, and harder at high tracking forces than Hertz's theory predicts." White cites numerous reasons explaining why Hertz's theory does not apply to phonographs. (2) "Experimental results ... at 6.32 kHz with a 0.7 mil stylus showed that losses were small at audio frequencies and that the resistance function was inversely proportional to the groove velocity in the range from 0.30 to 0.45 m/s. The hardness function, on the other hand, was independent of the groove velocity."
lucky, I note your continual vehement denial of vinyl compliance even in the face of Happ's most careful study of the complete problem.
It's not productive to try to change your fundamentalist mindset without further evidence in the 21st century so I will work on that ... as this evidence is useful for other practical stuff like digital EQ for cartridges.
But I DO want to know if your mythical model includes details of da rubber bung.
If it doesn't, it is seriously flawed. The evidence for this isn't just in Happ but is something I've tried for real and relatively easy for any one this Millenium with eg an Ortofon or ADC MM cartridge.
I've asked you this a couple of times without a response. Perhaps you are re-creating your mythical model ... which would certainly be appreciated by those of us pontificating on these arcane arts 🙂
It's not productive to try to change your fundamentalist mindset without further evidence in the 21st century so I will work on that ... as this evidence is useful for other practical stuff like digital EQ for cartridges.
But I DO want to know if your mythical model includes details of da rubber bung.
If it doesn't, it is seriously flawed. The evidence for this isn't just in Happ but is something I've tried for real and relatively easy for any one this Millenium with eg an Ortofon or ADC MM cartridge.
I've asked you this a couple of times without a response. Perhaps you are re-creating your mythical model ... which would certainly be appreciated by those of us pontificating on these arcane arts 🙂
Thanks for this George. I do want to do this but you will have to be patient.
In case it isn't obvious, I'm a real beach bum. I live in a shed and my speaker measuring space is also my bed & bedroom. (I sleep on the floor)
OK Ricardo. Take your time, I am not in a hurry 🙂
Only please, download these files now. Tomorrow will be late.
George
Only please, download these files now. Tomorrow will be late.
George
A shed! You're lucky. </monty Python>
Back on bungs, as they are causing me concern, not least as I'm going to start swapping them. I've started researching MM/MI construction techniques as I've not considered them much until recently and also it's fascinating to look at the trade offs. So far I have divided them into 'front wiggle' and 'rear wiggle' to group them according to where the bit that messes with the coils is. Grado and AT are both front wigglers. Ortofon is a rear wiggler and has 2 rubber donuts, one as the pivot and one as the damper. Now what I can't decide is if this is a genius bit of design, or just something optimised for pumping them off the production line. Or maybe both. Looking at AT who have a steel suspension wire and a teeny 'compliance adjustment screw' that can't be as easy to make?
Also some (slow) progress made and the experimentation turntable is serviced and ready for action. Haven't yet dared tell the wife it's older than her 🙂
Back on bungs, as they are causing me concern, not least as I'm going to start swapping them. I've started researching MM/MI construction techniques as I've not considered them much until recently and also it's fascinating to look at the trade offs. So far I have divided them into 'front wiggle' and 'rear wiggle' to group them according to where the bit that messes with the coils is. Grado and AT are both front wigglers. Ortofon is a rear wiggler and has 2 rubber donuts, one as the pivot and one as the damper. Now what I can't decide is if this is a genius bit of design, or just something optimised for pumping them off the production line. Or maybe both. Looking at AT who have a steel suspension wire and a teeny 'compliance adjustment screw' that can't be as easy to make?
Also some (slow) progress made and the experimentation turntable is serviced and ready for action. Haven't yet dared tell the wife it's older than her 🙂
Attachments
There's also the B&O MMC system which is a 'front' wiggler.
Front wiggle allows the tie wire to help set a 'precise' pivot location eg the AT compliance adjuster.
I'd like to know if the other big rear wiggles like Stanton, Empire, Goldring use a tie wire like SHURE?
Anyone seen a good explanation of the pros & cons .. or even marketing BS 🙂
Thanks George. I downloaded them as soon as they appeared and they are stored with the #853 & #864 WAVs.
I've found nothing on the pros and cons. Patent search is the next step. I had hoped one of you who had lived through it might now as I am (just) too young.
@George: In my dissection of an A&R C77 I realised that your superglue experiments were absolutely on the right track as the plastic surround is a key stiffener in what is otherwise a wobbly metal box!
@George: In my dissection of an A&R C77 I realised that your superglue experiments were absolutely on the right track as the plastic surround is a key stiffener in what is otherwise a wobbly metal box!
Thanks, Charlie - I will find and read it.
Right - for that 0.7 mil stylus at 6.32kHz, hardness (typically correlates to elasticity) is reported to stay constant with groove velocity, while resistance (typically correlates to damping) decreases with increasing groove velocity. Ya gotta love the contact mechanics of viscoelastic polymers ...
It's understandable that Happ, Groh et al decided to measure the stylus/groove response for their stylii to inform the Shure models and I find myself more and more drawn to the experimental approach. Does anyone out there have a linear variable differential transformer probe with micro-metre resolution? Then we could calibrate one of those fancy piezos that Scott found, feed it a wide-band sine sweep to stimulate a real cart bearing a real tracking force while attached to a real tonearm so that we can record the output, resonances and all. Any capacity or interest?
We have somewhere a small linear stage with 9 digits of resolution but I don't know of any LVDT's with useful sub micron resolution. We spend 1000's at Thor labs maybe I could get a sample or two and just see trusting to the first order that they are flat, considering the 400kHz self resonance this should be generally true. We don't need any absolute amplitude cal just flatness of the excitation.
A small output transformer run backwards should do for the 100V drive, this can be put in a feedback loop to keep it flat with frequency.