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Skeptoid: Digital vs Vinyl, Podcast casts its skeptical eye on digital audio
Nessuno
post Apr 3 2012, 17:31
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QUOTE (Arnold B. Krueger @ Apr 3 2012, 15:42) *
QUOTE (Nessuno @ Mar 29 2012, 06:26) *

Maybe the sense is that the practical limits of common hardware prevent you to reach the theoretical ones of the format?


Many of the limits are not due to the use of common hardware, but due to the fact that even the best hardware ever made couldn't do anything about them.


Absolutely true! In fact upon reading again, I'd better used the term "real" in place of "common" (sorry for lexical imprecision from non English speaker. smile.gif)

And speaking about analog sources, vinyl but tape as well, while what you precised holds true, it's true also that just because the tendency towards the theoretical limits is kind of asymptotic, on costs increase there could be an increase of perceivable musical performances. Now, it's not so difficult to understand why subjectivists and less technically educated music lovers are easily leaded to think that this same "cost vs performance curve" apply to digital sources too.
All the more, as normally analog performance increases come from visible mechanical improvements (heavier platters or capstans, lighter cartridges and shells etc...), the same people is easily fooled into thinking that better tangible built of an electronic device automatically means better musical performances!

This post has been edited by Nessuno: Apr 3 2012, 17:40


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kraut
post Apr 3 2012, 17:52
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QUOTE
Then there is the FM distortion caused by ............ offset angled tone arms (IOW not straight line).


That can be easily avoided:


By kraut_2 at 2009-03-27



QUOTE
[Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record.

Where is the proof? Just claims pulled out of your behind?

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mzil
post Apr 3 2012, 23:32
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QUOTE (Arnold B. Krueger @ Apr 3 2012, 08:45) *
QUOTE (mzil @ Mar 30 2012, 03:33) *
QUOTE (knutinh @ Mar 30 2012, 01:36) *
Or, do a high-resolution digital recording of vinyl, play it back at high-resolution and CD-resolution in an ABX test.

-k

That way wouldn't be comparing direct analog LP sound to digital, though; it would be comparing two kinds of digital sound.


So what?

We already know from other experiments that reasonably good digital is sonically transparent, and the very best digital bests the thresholds of human hearing by orders of magnitude.


I dont think comparing two digital recordings will pass muster with the segment of vinylphiles who think there's something "better" about LPs than CD, in a comparison test they would agree is valid, at least. I suspect they would argue that one of the sources of the test actually be direct LP playback, not a recording of it we insist is "indistinguishably just as good to the human ear".

A well designed test should pass muster with people on both sides of the argument, not just one.

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Woodinville
post Apr 4 2012, 06:19
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QUOTE (kraut @ Apr 3 2012, 09:52) *
QUOTE
[Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record.

Where is the proof? Just claims pulled out of your behind?


Perhaps you should actually read up on the read mechanisms involved with contact stylii, and about plastic and elastic deformation in vinyl.

Your unnecessarily rude, inaccurate professional accusation aside, I am not making a statement that is in any way outside the arena of common knowlege of vinyl. If, for instance, you bother to read the AES collections on vinyl, you will find what you seek.


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kraut
post Apr 4 2012, 15:59
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QUOTE
Perhaps you should actually read up on the read mechanisms involved with contact stylii, and about plastic and elastic deformation in vinyl.


Yes, I have done that enough over the last fifty years I play back vinyl.
The statement was done categorically - so who please is unprofessional here - without reference to cartridge mass, tracking weight, tracking angle (not existing in tangential arme, airbearing or motor driven) etc. etc. I for instance run wet, so some lubrication of the interface stylus/track walls is provided reducing friction.
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stephan_g
post Apr 4 2012, 22:36
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QUOTE (kraut @ Apr 3 2012, 17:52) *
QUOTE
Then there is the FM distortion caused by ............ offset angled tone arms (IOW not straight line).


That can be easily avoided:


By kraut_2 at 2009-03-27

To the best of my knowledge, linear trackers also have a non-zero (if constant) tracking angle since the cartridge has to drag the tonearm along. One would hope that those of the better kind used some kind of servo ( la power steering) to minimize both force and tracking angle, otherwise I'd imagine bearing friction would be extremely critical.

I'm awfully grateful for digital technology, that's for sure. It takes so many ifs and buts out of the equation it's not even funny. Just compare where a $150 record player and $150 CD player are on their respective diminishing returns scales in terms of output quality - absolutely no contest. Not to mention $50 DAPs and soundcards...
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splice
post Apr 5 2012, 01:45
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QUOTE (stephan_g @ Apr 4 2012, 14:36) *
... To the best of my knowledge, linear trackers also have a non-zero (if constant) tracking angle since the cartridge has to drag the tonearm along. One would hope that those of the better kind used some kind of servo ( la power steering) to minimize both force and tracking angle, otherwise I'd imagine bearing friction would be extremely critical. ...


Many non-servo linear trackers use an air bearing (air is blown into the gap between the sleeve the tonearm is attached to, and the rod it slides on.) The arm platform has to be very precisely leveled, and the arm wires have to be carefully dressed (see the wires in the posted picture). For a good example of a servo powered integrated arm and turntable, consider the Technics SL-10 and SL-15.


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Woodinville
post Apr 5 2012, 03:50
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QUOTE (kraut @ Apr 4 2012, 07:59) *
QUOTE
Perhaps you should actually read up on the read mechanisms involved with contact stylii, and about plastic and elastic deformation in vinyl.


Yes, I have done that enough over the last fifty years I play back vinyl.
The statement was done categorically - so who please is unprofessional here - without reference to cartridge mass, tracking weight, tracking angle (not existing in tangential arme, airbearing or motor driven) etc. etc. I for instance run wet, so some lubrication of the interface stylus/track walls is provided reducing friction.


Doesn't matter, the acceleration of the stylus is the issue.

Of course, you can make it a lot worse if you try.

Now, you've claimed expertise, eh? Mine is public knowlege, please show your fully and without doubt, and do so immediately.

I'll say it again, every play of vinyl causes some amount of damage unless you've got one of those laser turntables.
What's more, two plays in a row, with little time in between plays, is even worse.

I'm simply citing the known facts. You claim otherwise, well, show us your evidence. Your claim is the extraordinary one, so you owe us extraordinary evidence.


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Woodinville
post Apr 5 2012, 03:53
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QUOTE (splice @ Apr 4 2012, 17:45) *
Many non-servo linear trackers use an air bearing (air is blown into the gap between the sleeve the tonearm is attached to, and the rod it slides on.) The arm platform has to be very precisely leveled, and the arm wires have to be carefully dressed (see the wires in the posted picture). For a good example of a servo powered integrated arm and turntable, consider the Technics SL-10 and SL-15.


Some force must be exerted, somewhere, in order to track, no matter how low the friction, because few, if any modern vinyl records have an absolutely constant pitch.

What's more, for something close to frictionless, we have some interesting issues in tracking bass in the L+R signal, I'd say. Of course, that system resonance is PROBABLY way below any such issue, so now we have to ask how it interacts with warpage, decentering, etc.

Physics works.


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Nessuno
post Apr 5 2012, 07:59
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QUOTE (Woodinville @ Apr 1 2012, 00:10) *
Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record.


Not to mention that, more prosaically, every time you take a record out of its sleeve, no matter how careful you can be, that's a scratch waiting to happen... after that you will never get back the same signal! wink.gif

This post has been edited by Nessuno: Apr 5 2012, 08:01


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Engelsstaub
post Apr 5 2012, 15:04
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QUOTE (Nessuno @ Apr 5 2012, 01:59) *
...every time you take a record out of its sleeve, no matter how careful you can be, that's a scratch waiting to happen...


I find that about 1 out of 3 to 4 records I buy new today are already warped and/or have factory machine and handling marks right in the damned grooves. Sometimes I ask myself why I keep buying them.

I don't mind some surface noise and a few snaps every now and then. I don't even mind the seeming pain in the ass that vinyl is compared to CDs. What I do mind is paying more money for a record than the CD and getting a faulty or a defective product. The "limitations" of vinyl and clarity of a CD are of no consequence to me. I just want to collect and enjoy music.

...hard to enjoy music when it's pre-handled carelessly and sold for a premium. (CDs have stayed about the same in price since their inception.)


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krabapple
post Apr 5 2012, 17:55
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QUOTE (Engelsstaub @ Apr 5 2012, 10:04) *
I find that about 1 out of 3 to 4 records I buy new today are already warped and/or have factory machine and handling marks right in the damned grooves. Sometimes I ask myself why I keep buying them.


It was ever thus (or at least, it was thus in the 1970s and early 1980s, my prime LP-buying days)

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kraut
post Apr 6 2012, 06:28
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QUOTE
[Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record.


I responded to this specific claim. He claims, he has to supply the proof. Not the other way round.

I never stated anything categorically as he did. I am fully aware that over many playbacks vinyl will gradually deteriorate. That's why I playback records wet and remove the residual moisture after playback.
I again ask - where is his proof other than in his anus?

Any measurements as to heat generation between stylus and vinyl at the contact surface? Any measurements of actual deforming happening at the stylus/vinyl surface interface? Any calculation as to the forces exerted by the stylus impacting the vinyl as to time and surface area involved and the resulting deformations, both permanent and temporarily? All that in the lateral ant horizontal planes please.
Any differences between pivoted and tangential arms, differences between various tracking forces, raking angles VTA etc. Differences between cartridges of various compliance?
As you might have gathered from my question for proof: the categorical statements peddled are nonsense considering the parameters and possible variations involved.

As you point out - your knowledge is public - please demonstrate.

I have read over the years so many conflicting statements and so called research as to the topic of vinyl playback and stylus/medium impact that I doubt there is any conclusive statement to be made.
That is why ask for evidence, not idiotic statements.

QUOTE
[Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record.


I find this claim absolutely hysterical in light of so many audiophile;e nonsense one has to contend with on other forums. It reminds me of the claims that everything will make a difference, be it shun mook discs, cryogenated cables, rhodium vs. gold plating etc.
Why is his statement not treated with the usual contempt and reference to TOS 8 or whatever number is applicable as to audibly tested evidence? I am asking not even for that - show me some fucking measurements.

And if you think my language is offensive - so be it, some statements do not deserve better than being severely offended against.

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kraut
post Apr 6 2012, 07:37
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QUOTE
Where is the proof? Just claims pulled out of your behind?


My reply to an unproven assertion.

His response:
QUOTE
I'm simply citing the known facts. You claim otherwise, well, show us your evidence. Your claim is the extraordinary one, so you owe us extraordinary evidence.


Known? Where is the beef? Sounds very much like any audiophile statement I ever heard of. Where I did claim anything? I just asked for evidence and I have to supply evidence for a question? Any idea of scientific approach at all? Or how to treat requests - even impolite ones - for evidence? And on top playing the authority card? Any familiarity with skepticism?
Are you the pope of vinyl?
QUOTE
If, for instance, you bother to read the AES collections on vinyl, you will find what you seek.


Very arrogant and disingenuous, as almost all AES papers are behind a pay wall.

I am not sorry. I am an old grouch close to retirement and do not take to bull from whoever claims authority at face value any more. Show me the evidence and convince me, otherwise shut up.

I hardly ever play vinyl lately, relying on my server for playback, but I still do not accept unproven or undocumented claims from anybody about anything.
My experience in vinyl over 50 years have audible proven to me that records when well treated can play with only minor surface noise repeatedly for a long time; that is why I do not accept statements like the one I keep harping about with out supporting evidence.

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splice
post Apr 6 2012, 07:44
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QUOTE (kraut @ Apr 5 2012, 21:28) *
QUOTE
[Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record.


I responded to this specific claim. He claims, he has to supply the proof. Not the other way round. ...


Somewhere in my (paper) files I have a copy of a study performed in the early 80s that examined what happens to a played disc. It included observations on how long a groove takes to recover from the elastic deformation caused by playing. I can't remember the exact numbers, but I was surprised by how long it took. I haven't found the article yet, but while I was looking I did find something on wet playing:

QUOTE (kraut @ Apr 5 2012, 21:28) *
... I playback records wet and remove the residual moisture after playback.


I found a report from a seminar presented by the Discwasher company, summarising the results of some two years of research into the interaction between vinyl disc records and pickup cartridges. Their research naturally included the effects of cleaning fluid.
" ... In one test, a 4 Khz test record was treated with de-ionised water and it was noted that there was a small increase in distortion; but after it had dried the distortion shot up by 20 to 25 dB - and similar results were had with an intermodulation distortion test record. Re-wetting the records brought the idstortion down again, but not to the original levels. Thus wet playing causes a permanent increase in harmonic and IM distortion.
For verification, records were wetted but not played and the eventual conclusion was that the water reacted with chemicals in the vinyl, causing a "puckering" effect. A more detailed explanation came from Dr. Bruce Maier (Discwasher principal), who put most of the blame onto stabilisers that are put into the record for anti-static and other reasons. One of these compounds is a co-polymer resin, vinyl acetate. This dissolves in water, but when it re-forms it makes hard ridges and bumps. I quote Dr. Maier: 'We postulated that acetic acid would be formed in this reaction, so we played the record twice - if the acid was there we thought it needed stirring before we could measure it. Lo and behold, the pH had increased 20 to 30 times. Once that acid is formed, it starts an automatic hydrolysis of the record surface. Now the record dries and spectral analysis reveals that these interfacial changes on the surface of the record cause a permanent puckering.'"

I'll keep looking for the deformation article. Only 11 folders to go...

This post has been edited by splice: Apr 6 2012, 07:46


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Nessuno
post Apr 6 2012, 07:56
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QUOTE (kraut @ Apr 6 2012, 07:28) *
And if you think my language is offensive - so be it, some statements do not deserve better than being severely offended against.


Yes, yes... but I do think you'd better save your offenses for more serious matters: here we're only chatting about fuck(... beep... ahem... rolleyes.gif ) musical devices!


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kraut
post Apr 6 2012, 08:12
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I play with a mixture with distilled water and 99% isopropyl alcohol (30% down mixed), and remove the liquid from the record surfaces immediately after playback is ended, removing any dirt, and eliminating static buildup.
Unfortunately the cited study was done by a company definitely not unbiased, with a stake in selling their particular product. So I have a problem trusting a study that runs contrary to my own experience over many many years, with the practices I employ.

This study reminds me too much of similar ones by various cable companies when citing skin effect (existing in any cable but completely irrelevant to audio) or capacitance to push their products publishing "white papers" (like white vans?)
QUOTE
Dr. Bruce Maier (Discwasher principal), who put most of the blame onto stabilisers that are put into the record for anti-static and other reasons. One of these compounds is a co-polymer resin, vinyl acetate.


The question is: as a copolymer it is not a freely available chemical, but bound in the polymer matrix. How reactive is it in this form at all? Again - another claim/blame without evidence?

QUOTE
Lo and behold, the pH had increased 20 to 30 times. Once that acid is formed, it starts an automatic hydrolysis of the record surface. Now the record dries and spectral analysis reveals that these interfacial changes on the surface of the record cause a permanent puckering.'"


That shows how "scientific" this so called Dr. is. An increase in pH does not means in increase in acidity, just the opposite. What an asshat....
This statement clinches this article for me: shilling for a company without even getting basic chemistry correct. Sounds like homeopathy....

QUOTE
but I do think you'd better save your offenses for more serious matters


What, you think audio is not a serious matter...where are your priorities, you question my life's purpose....who could you??

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greynol
post Apr 6 2012, 08:23
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The topic at hand is not about the manner in which we are expressing ourselves. That said let's have a little more respect.


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Woodinville
post Apr 6 2012, 10:42
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Since I am not going to go buy an expensive, obsolete book in order to satisfy an individual's need to re-learn what is already understood in the art, I will simply cease participation in this thread.

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splice
post Apr 6 2012, 12:18
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QUOTE (kraut @ Apr 5 2012, 23:12) *
I play with a mixture with distilled water and 99% isopropyl alcohol (30% down mixed), and remove the liquid from the record surfaces immediately after playback is ended, removing any dirt, and eliminating static buildup.


"Maier also fingered the alcohol base of some record treatments as a particular threat to the record's stabilizers." - Article in Billboard magazine, September 1980. (My original quotes were from a UK music magazine.)

QUOTE (kraut @ Apr 5 2012, 23:12) *
Unfortunately the cited study was done by a company definitely not unbiased, with a stake in selling their particular product. So I have a problem trusting a study that runs contrary to my own experience over many many years, with the practices I employ.


Their research was done to identify causes of audible degradation from application of record cleaning or anti-static formulas, and formulate a product that minimised such damage. The point is that they did the research and produced actual figures and analyses, as well as being awarded several patents based on the work. Your supporting research for your assertion that it does no harm is... what?

QUOTE (kraut @ Apr 5 2012, 23:12) *
The question is: as a copolymer it is not a freely available chemical, but bound in the polymer matrix. How reactive is it in this form at all? Again - another claim/blame without evidence?


It should be easy enough to prove by anyone with a chemistry education. The discwasher patents are available online, but I'm not a chemist.

QUOTE
Lo and behold, the pH had increased 20 to 30 times. Once that acid is formed, it starts an automatic hydrolysis of the record surface. Now the record dries and spectral analysis reveals that these interfacial changes on the surface of the record cause a permanent puckering.'"


QUOTE (kraut @ Apr 5 2012, 23:12) *
That shows how "scientific" this so called Dr. is. An increase in pH does not means in increase in acidity, just the opposite. What an asshat....


I would tend to place the blame on the reporter. "20 to 30 times" should have been a clue. He also said Maier was a physicist, whereas a former Discwasher employee says he was a biochemist:
http://www.audioasylum.com/mhtml/m.html?fo...vinyl&n=207

I'm not saying you shouldn't wet play. I did it any time I found a disc with an intractable static or surface noise problem. I'm just pointing out that your belief that the practice is harmless is not supported by the facts.




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2Bdecided
post Apr 6 2012, 12:50
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QUOTE (kraut @ Apr 6 2012, 07:37) *
My experience in vinyl over 50 years have audible proven to me that records when well treated can play with only minor surface noise repeatedly for a long time
I could say the same (though not quite so many years), but we humans are largely unable to detect small amounts of harmonic distortion. We're also bad at spotting small changes in anything that happen little-by-little over a large time frame, especially if we are there to see each stage of the change (e.g. a son we see every day doesn't seem to grow; a nephew we see once a year is seen to grow a lot each time).

For both reasons, our subjective judgement of how well records wear, especially from a time long before we digitised them to the time we finally digitised them, should be taken as the vague anecdote it is.

Taking a test record, digitising it, then intentionally wearing it out, would be a robust test. Though frankly, I'd only really want to know about preventable wear. Unpreventable wear that I otherwise won't notice is probably best not known about - like coding artefacts in content that I can only acquire via lossy source, it's better if I don't notice them, and better if I don't know they're there so I don't try to notice them or imagine I can hear them.

Cheers,
David.

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Arnold B. Kruege...
post Apr 6 2012, 14:52
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QUOTE (kraut @ Apr 3 2012, 12:52) *
QUOTE
Then there is the FM distortion caused by ............ offset angled tone arms (IOW not straight line).


That can be easily avoided:


By kraut_2 at 2009-03-27



QUOTE
[Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record.

Where is the proof? Just claims pulled out of your behind?


Well known problem - the vinyl groove is significantly distorted by the relatively high pressures at the point the stylus touches the groove, such that there is even a little pool of molten vinyl in there.

From AES paper:

"Role of Scanning Electron Beam Microscope in Disc Recording"

http://www.aes.org/e-lib/browse.cfm?elib=3080

"Evidence of thc fact that vinyl melts can be found in pictures taken of record grooves played at different temperatures."

http://www.delback.co.uk/lp-cdr.htm

"When you play an LP, the (hard) diamond stylus deforms the (soft) vinyl groove. When played normally (ie. dry), the friction causes the vinyl to heat up, which allows it to deform and return to its original shape after a while"
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DonP
post Apr 6 2012, 14:54
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QUOTE (splice @ Apr 6 2012, 02:44) *
Lo and behold, the pH had increased 20 to 30 times.


Taking it from roughly neutral (7) to around 160? I've never heard of anything that basic... no doubt it would dissolve right through stainless steel.

They didn't by chance mention 300 dBA speakers in the same article?

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krabapple
post Apr 6 2012, 20:23
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If you're a masochist there's always this 20-page thread of vinylphiles debating virtues of wet LP play. With math to prove it!
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krabapple
post Apr 6 2012, 20:49
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and, btw, the AES e-library is free to search. Results are returned with abstracts.

e.g. 'vinyl' gets 293 hits, here's a few I foudn particularly interesting:

QUOTE
The Limiting Tracking Weight of Gramophone Pickups for Negligible Groove Damage

It has been observed that when spherical styli are dragged over flat vinyl surfaces, scratches are produced under loads considerably exceeding the elastic limit as calculated from theory. The author, in this paper, describes the results of his experiments which bear out his argument that under load the point of yield begins below the surface; and reaches the surface, producing visible tracks, only after the calculated yield load is exceeded. This critical value of load for styli of various radii has been measured and found to be equivalent to, for a 1-mil stylus, 0.64 gm. for a 90 record groove. No size or skin effect was found with the vinyl material tested.

Author: Barlow, D. A.
Affiliation: Aluminium Laboratories, Ltd., Banbury, Oxon., England
JAES Volume 6 Issue 4 pp. 216-219; October 1958


QUOTE
Groove Deformation and Distortion in Recordings

The elastic and plastic deformation of vinyl record compound under indenters of various profiles has been studied in large-scale tests. Curves of total depth of penetration versus load have been used to calculate the net distortion on record playback. In general, in the lower treble, net distortion is less, and in the upper treble, net distortion is greater than tracing distortion alone. This is important for attempts to reduce tracing distortion by inverse predistortion of the recorded signal. Nylon was also studied as a material with contrasting mechanical properties to vinyl. Further light has been shed on the nature of translation loss.

Authors: Barlow, Donald A.; Garside, Gerald R.
JAES Volume 26 Issue 7/8 pp. 498-510; August 1978


QUOTE
Comments on "On Stylus Wear and Surface Noise in Phonograph Playback System"
When a set of conclusions is reached in a study as fundamental as this, it is certain that particular factors have been accepted as a part of the working hypothesis essential to the formulation of conclusions which are open to challenge by another student of the subject. Mr. Barlow's studies, like those of Prof. Hunt, are thorough and represent another view of the same subject. Almost invariably, the points of departure in such cases become the focal points for study by all concerned. The process of further investigation usully results in the collection of additional test data that removes the subject from the realm of scientific speculation, and places it within the established body of knowledge of the art. Readers wishing to offer supporting or different viewpoints of their own for publication are invited to address them to the Editor. Such comments are especially welcome.

Author: Barlow, D. A.
JAES Volume 4 Issue 3 pp. 116-119; July 1956


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Determination of Sliding Friction Between Stylus and Record Groove

A method is presented for determining the coefficient of sliding friction between stylus and record groove. The method consists of measuring the time intervals required for a freely rotating record (on a turntable) to decelerate from one known speed to another, both with and without a stylus sliding in the record groove. The method as been used to evaluate the frictional characteristics of several brands of phonograph records in mind condition and after treatment with various preservatives, cleaners, and antistatic agents. Some test results are presented
Author: Pardee, Robert P.
Affiliation: Ball Corporation, Aerospace Systems Division, Boulder, CO
JAES Volume 29 Issue 12 pp. 890-894; December 1981

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Disc Record Care and Cleaning Accessories

Since the paper presented by me on a similar theme to the 50th AES Convention at the Cunard International Hotel in London in 1975, investigations into developments in this area have been pursued vigorously both in the UK and in other countries to tackle the problems of -record cleaning- and maintenance.

Author: Aldous, Donald
Affiliation: Hi Fi News and Record Interview, Plymouth
AES Convention:65 (February 1980)


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An Investigation into the Increase of Non-Linear Distortion Products from Virgin Tape to Disc Playback

A study was carried out in order to examine the increase in distortion products arising from the various stages in the recording process from virgin tape, via tape copies, right up to and including interaction with specific record pick-up distortions. 1 kHz sinusoidal signals as well as some IM (400 + 4000 Hz) and double tone (9800 + 10200 Hz) signals were recorded at levels increasing in discrete 3 dB steps starting in non-critical range and continuing up to tape compression level. The tape -original- and first and second generation copies were then transcribed together onto 12" LPs. This made possible a study of the distortion progression and also the second and third order distortion combination products. The current practice of recording right up to the modulation limits of the tapes as well as of the disc seems to result in a total distortion percentage which considerably degrades the sound quality. In order to gain an impression of the audible effect of these distortions, some special musical samples were recorded with the same discrete level steps as the measuring signals. These musical samples were subjected to the same copying and transcription processes as the measuring signals and were similar in character (single tone, multi tone). Listening to these musical sample records provided an opportunity to establish perceptibility limits for the human ear regarding amounts of disturbing distortion.

Authors: Stephani, Otfried; Blthgen, Bjrn
Affiliation: Polygram GmbH, Hanover, Germany
AES Convention:62 (March 1979) Paper Number:1453


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An Experimental Study of Groove Deformation in Phonograph Records

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.

Author: White, James V.
Affiliation: Acoustics Research Laboratory, Harvard University, Cambridge, MA
JAES Volume 18 Issue 5 pp. 497-506; October 1970


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Factors Affecting the Needle/Groove Relationship in Phonograph Playback Systems

It is shown that a phonograph pickup stylus riding in the groove of a record partly penetrates the groove walls because of elastic and plastic deformation of the record material. At high bearing loads complete plastic flow sets in and the needle leaves a permanent indentation track, while at lower loads the elastic deformation is predominant. This leads to amplitude distortion in the reproduced signal which may be of two types: one which is a function of the recorded wavelength (G function or translation loss), the other a function of the dynamic moving mass of the stylus/armature (H function or stylus/groove resonance). A third phenomenon (S function or scanning loss) is caused by the finite size of the stylus/groove-wall contact surface. Experiments with specially built pickups show the evolved theory to be valid even for very high frequencies. Special test records with recorded frequencies up to 100,000 Hz were used for these experiments.

Author: Bastiaans, C. R.
Affiliation: Westinghouse Research Laboratories, Pittsburgh, PA
JAES Volume 15 Issue 4 pp. 389-399; October 1967
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