I assume it is computed from the Young's modulus of vinyl and the dimensions at the scale of an actual LP. My question is does this scale to a 100' thick LP and a giant stylus with 100's of tons of tracking force. These problems have variables that scale as dimension, dimension squared, and dimension cubed, and you have to keep them straight.
I read an analogy years ago that stuck with me. Imagine the record scaled up to the size where you could sit on the land and dangle your feet over the edge of a groove 3 feet deep. The smallest stylus made (then, probably still) would be 20 feet tall and mounted on a cantilever the length of (an American) football field.
The interesting bit to me is that these things *don't* scale. Our imaginations fail us, to some extent - not Bybee extent, but some. Vinyl records grew pretty much ad hoc, like living things, and you wonder if they had started from a clean sheet of paper would anybody have actually tried? - it seems so improbable. Fun though.
Much thanks, as always,
Chris
The interesting bit to me is that these things *don't* scale. Our imaginations fail us, to some extent - not Bybee extent, but some. Vinyl records grew pretty much ad hoc, like living things, and you wonder if they had started from a clean sheet of paper would anybody have actually tried? - it seems so improbable. Fun though.
Much thanks, as always,
Chris
I agree on one thing, losing DF96 has made me rethink the whole point of this.
Be of good cheer. And, he was not a quitter, he was a fighter for truth. Stay the fight. You're needed.
Chris
Chris
At 5cm/S of recording velocity with a 33&1/3 RPM record the grove velocity in the middle or so would be 50cm/S. This would give a pressue angle of less than 6 degrees. So one would should not be surprised to see the attendant reduction in side force.
The should be even more as we normally don't record square waves. Also the effect of mixing horizontal and vertical modulation should reduce the equivalent force per unit area even more.
The should be even more as we normally don't record square waves. Also the effect of mixing horizontal and vertical modulation should reduce the equivalent force per unit area even more.
This is probably her master piece. Back to the church, a live of two nights of gospels, with just her musicians playing organ, bass and drums, and all the congregation singing with her, recorded as-it (fantastic technical quality) Two nights, two CDs. Her voice and her piano: A miracle.
I think everybody remember her at the white house, making Obama crushing a tear:
YouTube
Can't count how many times I've watched this, but I cry every time as well.
I will miss her for the rest of my life ... and specially those last 3 years ...
Could it be possible, on earth, that one day, another human would sing like her ?
That's an interesting point that force is skewed towards the leading face of the groove wall. It's still the same amount, because that comes from simple Newton, but not orthogonal. Makes sense to my pea-brain.
My take-away from the whole taco is just one of shear magnitude. It's several orders of magnitude beyond a wildass guess. And even the WAG would need a couple of beers to believe.
Much thanks,
Chris
Would such a thing like truth exist?
The wars of religion will not have made enough victims?
I often have the impression that we are going back to the middle ages. It's scary, really.
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If you lived in America right now, I think you would not take truth so lightly.
Always good fortune,
Chris
Always good fortune,
Chris
Chris, please, just try to consider more deeply* what i wanted to express.
There is lies, it is a will to disguise the truth. most of the time for dishonest reasons. But "the truth", I don't see. It's ever just a point of view.
*The opposite to "lightly".
[Edit] In a way or another, we all live in America, right now. And it is scary too.
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Indeed. In a different vein, you might enjoy this:
"There are so many things our eyes don't see. But the camera sees everything. We are too clever, and our cleverness plays us false. We should trust mainly our feelings and those senses that never lie to us. Our intelligence disturbs our proper vision of things."
- Robert Bresson
Probably even better in whatever wacky language you guys speak over there.
Much thanks, as always,
Chris
"There are so many things our eyes don't see. But the camera sees everything. We are too clever, and our cleverness plays us false. We should trust mainly our feelings and those senses that never lie to us. Our intelligence disturbs our proper vision of things."
- Robert Bresson
Probably even better in whatever wacky language you guys speak over there.
Much thanks, as always,
Chris
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Speaking of tacos... One of the stadiums I did, the architects selected a paint color and manufacturer that really did not make the quantity, quality, application friendly and low volatiles paint that the paint contractor normally used. As all the architect required was matching the color, the contractor bet a taco to one of the best paint manufacturer's salesman he could not match the color to the architects' satisfaction.
The better paint folks did match it and it was used to paint the whole place. They named that color "taco bet" and the name and color formula is still in their nationwide paint computer color system.
I did try to match it for the loudspeakers that used the RAL color system and failed! Just not available in the RAL color system.
The better paint folks did match it and it was used to paint the whole place. They named that color "taco bet" and the name and color formula is still in their nationwide paint computer color system.
I did try to match it for the loudspeakers that used the RAL color system and failed! Just not available in the RAL color system.
Perhaps Dave's faith in a higher power helped him keep things in perspective here, just a thought.
Afair, I've cited the paper before in the vinyl thread; Bastians wrote about the observation that vinyl at lower loads looks more stiff than the theoretical values predict.
"Below the critical load the material seems to behave as a much stiffer material."
"A last word on plastic flow: It is a known fact that the highest shear stress in the material below an indenter occurs at a point about half a contact-circle below the cent of contact (Davies). It has bees suggested that in the stylus/groove contact, sub-surface yielding begins near a load of .150 g and plastic yielding at the surface starts at loads in the range from 1 to 1.6g (using a stylus tip radius of 17.8 um)."
An interesting publication:
C.R. Bastiaans; Factors Affecting the Stylus/Groove Relationship in Phonograph Playback Systems; JAES, October 1967, Volume 15, No.4, 389 - 399
The plastic flow issue is the reason for the recommendation to let a record rest after replay before replaying again. At the moment I can't remember the time spans, but it was surely in the minutes range, so playing short snippets repeatedley isn't a good idea.
Even in the elastic case the actual contact area must be larger and so more in the case of plastic flow; for practical reasons as pressure would approach infinity for a point contact.
Bastiaan's article contains some informations and calculations for the contact area. As usual, if somebody in in need, drop me a note (Fair use)
Alexandrovich found in his SEM experiments excessive wear particles but used only water for the wet play and speculated about the cooling effect that prevents plastic flow as a reason:
""Our SEM pictures (Fig. 17, 18) unveiled extraordinary ripping of vinyl surface which I can explain only by the fact that the vinyl is not allowed to liquify momentarily under tile pressure of a fast moving stylus because of the cooling action of water in tile groove. This phenomlenon, I believe, is identical to ice skating where one does not skate on ice but actually on a film of water which comes from the ice being momentarily melted under tile pre'ssure of the thin metal blade. If ice is too cold, one cannot skate.
Evidence of the fact that vinyl melts can be found in pictures taken of record grooves played at different temperatures."
George Alexandrovich; Role of Scanning Electron Beam Microscope in Disc Recording; preprint no. 1274, 58th AES Convention, November 4-7,1977 New York
Interesting thesis to compare playing vinyl with skating.
It would at least explain why cleaning a record with a fluid has no negative impact while playing with it does.
If true, it would also mean that a stylus lubricant is not the way to go.
On the other hand Lucky Dog and I have both measured the surface noise coming from a blank groove, he with a “normal” arm and a tangential arm in my case.
We both played dry, wet, dry.
In his case noise went down significantly when playing wet, but was not the same anymore when going back to dry, as a sign that something changed to the groove.
In my case I had the same low noise in all three cases, no change whatsoever between the three recordings.
So maybe skating makes the whole equition even more complicated.
Hans
There is an important difference between plastic and elastic deformation.
There are locked groove test tracks.
I could post two 500Hz-50kHz sweeps taken seconds apart but to what avail? It has always been possible to actually demonstrate these effects by measurement, why has this not been done?
Because it's more productive, from a word count perspective, to endlessly waffle about it?
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