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Rip an LP with a scanner . . .

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Anonymous
July 17, 2005 2:12:56 AM

Archived from groups: rec.audio.pro (More info?)

http://www.cs.huji.ac.il/~springer/



It'll sound like ass, apparently, but so does my old Magnavox.







Kurt Riemann

More about : rip scanner

Anonymous
July 17, 2005 10:18:10 AM

Archived from groups: rec.audio.pro (More info?)

<Kurt Riemann> wrote...
> http://www.cs.huji.ac.il/~springer/
> It'll sound like ass, apparently, but so does my old Magnavox.

Imagine if he had spent his time on something useful and productive?
Anonymous
July 17, 2005 10:34:02 AM

Archived from groups: rec.audio.pro (More info?)

> Imagine if he had spent his time on something useful and productive?


Awwww, Mom, then it wouldn't be fun! :) 
Anonymous
July 17, 2005 12:21:22 PM

Archived from groups: rec.audio.pro (More info?)

<Kurt Riemann> wrote in message news:19tjd1p1ti4es85bvstmubp6oacv9h1fmi@4ax.com...
> http://www.cs.huji.ac.il/~springer/
>
>
>
> It'll sound like ass, apparently, but so does my old Magnavox.


Thanks for the laugh. :-)
Anonymous
July 17, 2005 3:26:59 PM

Archived from groups: rec.audio.pro (More info?)

In article <19tjd1p1ti4es85bvstmubp6oacv9h1fmi@4ax.com> Kurt Riemann <> writes:

> http://www.cs.huji.ac.il/~springer/
> It'll sound like ass, apparently, but so does my old Magnavox.

People are doing stuff like this (optically scanning the grooves of a
record and generating audio from the scans, for those of you not
curious enough to look at the web site) to retrieve otherwise
unplayable material. With a higher resolution scanner than your
typical home desktop unit and more powerful algorithms, they're doing
a better job than this guy did with his home rig.

Not perfect by any means, but it's another tool for recovering audio
from disks that aren't playable by conventional means any longer.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
July 17, 2005 4:41:30 PM

Archived from groups: rec.audio.pro (More info?)

In article <znr1121602093k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
>In article <19tjd1p1ti4es85bvstmubp6oacv9h1fmi@4ax.com> Kurt Riemann <> writes:
>
>> http://www.cs.huji.ac.il/~springer/
>> It'll sound like ass, apparently, but so does my old Magnavox.
>
>People are doing stuff like this (optically scanning the grooves of a
>record and generating audio from the scans, for those of you not
>curious enough to look at the web site) to retrieve otherwise
>unplayable material. With a higher resolution scanner than your
>typical home desktop unit and more powerful algorithms, they're doing
>a better job than this guy did with his home rig.

This is because they're actually looking at the groove cross-section.

The problem with just using a scanner, even a theoretically perfect one
of infinite resolution, is that you're looking at the _top_ of the groove
wall. And records aren't cut to have lowest distortion at the top of
the groove wall, they are cut to have lowest distortion at the point where
the groove is 1 mil wide. This means you need to get an accurate cross
section, find the point where the stylus is supposed to rest, and estimate
height and lateral position from that.

It can be useful to look at other parts of the groove, when dealing with
damaged records. The Finial allows you to do this in a fairly controllable
fashion.

There is a discussion of another nondestructive approach in the latest
issue of the JAES, which is well worth reading if you are interested in
this sort of thing. The guy who wrote it recently gave a talk to the
Washington DC chapter of the AES, but sadly not when I was in town.

>Not perfect by any means, but it's another tool for recovering audio
>from disks that aren't playable by conventional means any longer.

None of these systems have really proven themselves to be very useful.
The Finial is a fun gadget for dealing with particular sorts of groove
wear, especially on acetates which wear quickly and where the wear is
usually mostly from one turntable so it's all in the same place of the
groove. But for the most part, you can get quieter and lower distortion
playback with styli.

The big deal is reducing tracking distortion and tracing distortion.
Noise floor is no longer a big issue because it can be dealt with pretty
well in post-production, so people doing transfers are mostly willing to
sacrifice noise floor for improved impulse response today. This is very
different than it was when I started out, when noise floor was considered
everything.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 17, 2005 6:51:47 PM

Archived from groups: rec.audio.pro (More info?)

Kurt Riemann wrote:

> http://www.cs.huji.ac.il/~springer/
>
> It'll sound like ass, apparently, but so does my old Magnavox.

So, all that audio processing stuff on CSI *isn't* faked then ?
;-)

Graham
Anonymous
July 17, 2005 8:27:38 PM

Archived from groups: rec.audio.pro (More info?)

Richard Crowley wrote:

> <Kurt Riemann> wrote...
>> http://www.cs.huji.ac.il/~springer/
>> It'll sound like ass, apparently, but so does my old Magnavox.
>
> Imagine if he had spent his time on something useful and productive?

James Watt was told that my his mother. Fortunately he ignored her, which
is why we live in a technological civilisation.

--
JP Morris - aka DOUG the Eagle (Dragon) -=UDIC=- jpm@it-he.org
Fun things to do with the Ultima games http://www.it-he.org
Reign of the Just - An Ultima clone http://rotj.it-he.org
d+++ e+ N+ T++ Om U1234!56!7'!S'!8!9!KAW u++ uC+++ uF+++ uG---- uLB----
uA--- nC+ nR---- nH+++ nP++ nI nPT nS nT wM- wC- y a(YEAR - 1976)
Anonymous
July 17, 2005 8:27:39 PM

Archived from groups: rec.audio.pro (More info?)

"J. P. Morris" <jpm@it-he.org> wrote in message
news:42da782f$0$6302$ed2619ec@ptn-nntp-reader03.plus.net...
> Richard Crowley wrote:
>
>> <Kurt Riemann> wrote...
>>> http://www.cs.huji.ac.il/~springer/
>>> It'll sound like ass, apparently, but so does my old Magnavox.
>>
>> Imagine if he had spent his time on something useful and productive?
>
> James Watt was told that my his mother. Fortunately he ignored
> her, which is why we live in a technological civilisation.

Baloney. Buy "useful and productive" I mean actually breaking
new ground and/or doing something better, faster or cheaper.
This "experiment" was simply an entertaining waste of time.
Unless, of course, this was a 7th grade science fair project, etc.
and the point was learing the scientific experimental technique.

There are already people out there making serious attempts
at optical reading of black vinyl. I believe that at least one
of them is even commercially available.

If "~springer" had been serious s/he would have done the
research before reproducing a method that is not only
theoretically impractical, but has already been proved
actually impractical by others doing the same experiment.

If I wanted to make a serious attempt at this, I would use/
adapt optical disc reading methods (in particular, the
servo-correction of the optical read head position, etc.)
Anonymous
July 18, 2005 6:19:32 AM

Archived from groups: rec.audio.pro (More info?)

On 7/17/05 12:41 PM, in article dbe1nq$gei$1@panix2.panix.com, "Scott
Dorsey" <kludge@panix.com> wrote:

> None of these systems have really proven themselves to be very useful.
> The Finial is a fun gadget for dealing with particular sorts of groove
> wear, especially on acetates which wear quickly and where the wear is
> usually mostly from one turntable so it's all in the same place of the
> groove. But for the most part, you can get quieter and lower distortion
> playback with styli.
>
> The big deal is reducing tracking distortion and tracing distortion.
> Noise floor is no longer a big issue because it can be dealt with pretty
> well in post-production, so people doing transfers are mostly willing to
> sacrifice noise floor for improved impulse response today. This is very
> different than it was when I started out, when noise floor was considered
> everything.
> --scott

http://www.stereotimes.com/turn030300.shtm
Anonymous
July 18, 2005 7:47:55 AM

Archived from groups: rec.audio.pro (More info?)

On Mon, 18 Jul 2005 02:19:32 GMT, SSJVCmag <ten@nozirev.gamnocssj.com>
wrote:

>On 7/17/05 12:41 PM, in article dbe1nq$gei$1@panix2.panix.com, "Scott
>Dorsey" <kludge@panix.com> wrote:
>
>> None of these systems have really proven themselves to be very useful.
>> The Finial is a fun gadget for dealing with particular sorts of groove
>> wear, especially on acetates which wear quickly and where the wear is
>> usually mostly from one turntable so it's all in the same place of the
>> groove. But for the most part, you can get quieter and lower distortion
>> playback with styli.
>>
>> The big deal is reducing tracking distortion and tracing distortion.
>> Noise floor is no longer a big issue because it can be dealt with pretty
>> well in post-production, so people doing transfers are mostly willing to
>> sacrifice noise floor for improved impulse response today. This is very
>> different than it was when I started out, when noise floor was considered
>> everything.
>> --scott
>
>http://www.stereotimes.com/turn030300.shtm

The modern Finial. But aren't all of these gadgets just better
scanners (with correct views of the groove but without player
"jitter" correction, to use Arny's interesting term, but with
much better firmware?

Question #1: Shouldn't the issue of groove deformation during
recording become significant in reading the groove walls in
playback? And how are these related?

Question #2: Mechanical playback averages out several orders of
magnitude of physical "noise", including dust, vinyl imperfections,
etc. Optical software averaging has got to be significant to users,
but also proprietary, because difficult/expensive. Artifacts?

Question #3: What would be necessary to optically scan the surface
to enough resolution to include all (whatever that means) original
information?

Question #4: What is an appropriate algorism for the original
cutting surface deformation? Should we include another algorism
for expected playback geometric errors? (Don't laugh; RCA once
thought it correct).

Question #5: Since the current best answers to above #3 and #4
are likely proprietary, what are the next most relevant questions?

Thanks, as always,

Chris Hornbeck
"The political landscape is not all that different 30+ years later. I'm not sure
conservatives envy young people and liberals as much as 1970, but they fear
and hate them more." - aimless-46 from Kentucky reviewing _Joe_, 1970 on imdb
Anonymous
July 18, 2005 9:07:07 AM

Archived from groups: rec.audio.pro (More info?)

On Mon, 18 Jul 2005 03:47:55 GMT, Chris Hornbeck
<chrishornbeckremovethis@att.net> wrote:

>On Mon, 18 Jul 2005 02:19:32 GMT, SSJVCmag <ten@nozirev.gamnocssj.com>
>wrote:
>
>>On 7/17/05 12:41 PM, in article dbe1nq$gei$1@panix2.panix.com, "Scott
>>Dorsey" <kludge@panix.com> wrote:
>>
>>> None of these systems have really proven themselves to be very useful.
>>> The Finial is a fun gadget for dealing with particular sorts of groove
>>> wear, especially on acetates which wear quickly and where the wear is
>>> usually mostly from one turntable so it's all in the same place of the
>>> groove. But for the most part, you can get quieter and lower distortion
>>> playback with styli.
>>>
>>> The big deal is reducing tracking distortion and tracing distortion.
>>> Noise floor is no longer a big issue because it can be dealt with pretty
>>> well in post-production, so people doing transfers are mostly willing to
>>> sacrifice noise floor for improved impulse response today. This is very
>>> different than it was when I started out, when noise floor was considered
>>> everything.
>>> --scott
>>
>>http://www.stereotimes.com/turn030300.shtm
>
>The modern Finial.

From the brightly glowing review it's not hard to imagine that the
reviewer gets a substantial percentage of each sale.
Scott, however, is still in the pockets of the conventional
stylus/cartridge manufacturers. :) 

>But aren't all of these gadgets just better
>scanners (with correct views of the groove but without player
>"jitter" correction, to use Arny's interesting term, but with
>much better firmware?
>
>Question #1: Shouldn't the issue of groove deformation during
>recording become significant in reading the groove walls in
>playback? And how are these related?

What's the substance a record cutter cuts into? It surely doesn't
'deform' as the stylus cuts into it the same way vinyl deforms as a
playback stylus goes over it.

>Question #2: Mechanical playback averages out several orders of
>magnitude of physical "noise", including dust, vinyl imperfections,
>etc. Optical software averaging has got to be significant to users,
>but also proprietary, because difficult/expensive. Artifacts?

The review claims an analog signal path, which tells me that
software is not involved here. There appear to be several lasers, and
possibly several optical 'pickups' whose outputs can be added together
in different proportions, depending on things such as groove angle.

>Question #3: What would be necessary to optically scan the surface
>to enough resolution to include all (whatever that means) original
>information?

Molecular resolution? Nanotechnology? I know, use an STM (Scanning
Tunneling Microscope) to 'read' the groove - that would make a hellua
record player, but playback speed would have to be much slower than
real time, and each LP side would generate 40 gigs of information. But
after you've done it, you can 'play' the 'virtual LP' with any shape
and size stylus at any tracking angle.

>Question #4: What is an appropriate algorism for the original
>cutting surface deformation? Should we include another algorism
>for expected playback geometric errors? (Don't laugh; RCA once
>thought it correct).

Isn't this the same as, or very similar to Question #1, or am I
just not reading it right? I suspect it's been too many hours since
that last cup of coffee for one of us.

>Question #5: Since the current best answers to above #3 and #4
>are likely proprietary, what are the next most relevant questions?

Who has one and is reverse-engineering it? Probably the good folks
at [making up a possible domain name] v1ny1-hacker5-r-u5.com.

>Thanks, as always,
>
>Chris Hornbeck
>"The political landscape is not all that different 30+ years later. I'm not sure
>conservatives envy young people and liberals as much as 1970, but they fear
>and hate them more." - aimless-46 from Kentucky reviewing _Joe_, 1970 on imdb

-----
http://www.mindspring.com/~benbradley
Anonymous
July 18, 2005 10:22:07 AM

Archived from groups: rec.audio.pro (More info?)

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in
message news:u55md1906irkl7pu4ck4n7prilnkr3hclv@4ax.com

>> http://www.stereotimes.com/turn030300.shtm

I actually heard one of these playing at HE2005 this spring.
Didn't sound bad.

> The modern Finial. But aren't all of these gadgets just
better
> scanners (with correct views of the groove but without
player
> "jitter" correction, to use Arny's interesting term, but
with
> much better firmware?

The Finial doesn't so much scan the surface of the disk as
try to follow the position of a imaginary stylus with laser
beams.

> Question #1: Shouldn't the issue of groove deformation
during
> recording become significant in reading the groove walls
in
> playback? And how are these related?

It should be significant, but it should also be calculable.
Back in the day of I remember seeing technical papers (AES?,
IEEE?) with calculations that estimated groove tracking
error due to various effects, both geometric and
deformation. If it was calculable then, its calculable now.


> Question #2: Mechanical playback averages out several
orders of
> magnitude of physical "noise", including dust, vinyl
> imperfections, etc. Optical software averaging has got to
be significant to sers,
> but also proprietary, because difficult/expensive.
Artifacts?

Averaging is another one of those things that computers do
well.
Anonymous
July 18, 2005 11:13:49 AM

Archived from groups: rec.audio.pro (More info?)

Richard Crowley wrote:

> If I wanted to make a serious attempt at this, I would

Jesus, he's not making a serious attempt, he's just mucking around, and
what's wrong with that ? Get lost.

Alx
Anonymous
July 18, 2005 1:05:36 PM

Archived from groups: rec.audio.pro (More info?)

On Sat, 16 Jul 2005 22:12:56 -0800, Kurt Riemann <> wrote:

>http://www.cs.huji.ac.il/~springer/
>
>
>
>It'll sound like ass, apparently, but so does my old Magnavox.
>
>
-- A nice try, funny results -- but the author admits this. But I
remember a TV film, some 8 years ago, about the life in the USSR, from
the common man's point of view, and a man mentioned how they would
"dub" Western records using X-ray photo film sheets. I don't have a
clue how that things sounded and I presume they would take a kind of
photo of a record and a galvano process was further needed.

Toshiba made a try with an optical or menchanical/optical system in
the seventhies I think, I remember a picture of a round bulky head.

"Laser turntables" are interesting but they do need a trough
evaluation before spending the money -- a vacuum cleaner {why not a
decent record cleaning machine} is I think included in the price <g>.

Atltogether, an optical and contactless scanning of the groove is
interesting and it can be promising but the scanner head had to be not
much bigger than a common stylus I think. Otherwise, to all kind of
common distorsions, you should add optical distorsions too and that's
too much.

Edi Zubovic, Crikvenica, Croatia
Anonymous
July 18, 2005 1:28:08 PM

Archived from groups: rec.audio.pro (More info?)

"Alex Bird" <alex@redbeastie.fsnet.co.uk> wrote in message
news:1121696029.653780.301800@o13g2000cwo.googlegroups.com...
> Richard Crowley wrote:
>
>> If I wanted to make a serious attempt at this, I would
>
> Jesus, he's not making a serious attempt, he's just mucking
> around, and what's wrong with that ? Get lost.

We apparently agree that this was a silly lark.

Perhaps you meant to respond to "J.P.Morris" who
apparently thought this WAS a serious attempt.
Anonymous
July 18, 2005 2:36:27 PM

Archived from groups: rec.audio.pro (More info?)

Chris Hornbeck <chrishornbeckremovethis@att.net> wrote:
>>http://www.stereotimes.com/turn030300.shtm
>
>The modern Finial. But aren't all of these gadgets just better
>scanners (with correct views of the groove but without player
>"jitter" correction, to use Arny's interesting term, but with
>much better firmware?

Yes, but they are scanners that look at as much of the groove as
possible.

>Question #1: Shouldn't the issue of groove deformation during
>recording become significant in reading the groove walls in
>playback? And how are these related?

I'm not sure what you mean. The recording process _is_ groove
deformation.

A hot stylus with a facet cut in the front of it glides through
the acetate, melting as it goes through. It plows up little
furrows of "horn" on either side of the groove, which are sometimes
removed.

For the most part, the configuration of the stylus is set to give
a good compromise between noise, distortion, and stereo separation
on a conventional stylus playback. Some things can be varied by
source material: for example if you're cutting dance music you might
want to cut a much deeper groove to allow more out-of-phase bass.

There are some tricks that can be done in recording to compensate for
mistracking effects on playback, but for the most part they don't work
because playback systems are all so different from one another. Check
out some of the articles on Dynagroove in the RCA Review for a really
misguided set of ideas.

But even aside from that, there are a lot of effects that are known
and expected, and the cutting configuration can be changed while listening
to the playback a second later, to get the sound that the cutting engineer
wants.

>Question #2: Mechanical playback averages out several orders of
>magnitude of physical "noise", including dust, vinyl imperfections,
>etc. Optical software averaging has got to be significant to users,
>but also proprietary, because difficult/expensive. Artifacts?

Yes, using something like the Finial, the noise is very severe because
there are little pieces of dust that a stylus would knock out of the
way, but which the scanner detects as noise. Ultrasonic cleaning before
transcription combined with digital noise reduction is essential to make
the system work usably.

>Question #3: What would be necessary to optically scan the surface
>to enough resolution to include all (whatever that means) original
>information?

You want _more_ than just the original information, you also want to
accurately record whatever artifacts exist.

>Question #4: What is an appropriate algorism for the original
>cutting surface deformation? Should we include another algorism
>for expected playback geometric errors? (Don't laugh; RCA once
>thought it correct).

The problem is that it's different for different records. Some
recordings were cut into soft acetate, others into harder acetate.
Some folks used one facet configuration on the cutter, others used
another. Many records are dehorned, which causes information to be
list. Others are not. DMM changes all the rules.

The thing is, records are basically cut with the intentention of
compensating for geometric errors on playback already. Folks fiddle
around with different configurations until they can get the sound they
want on playback.
>
>Question #5: Since the current best answers to above #3 and #4
>are likely proprietary, what are the next most relevant questions?

I find that asking how it sounds is _never_ a bad question.
-s-cott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 18, 2005 2:43:40 PM

Archived from groups: rec.audio.pro (More info?)

Ben Bradley <ben_nospam_bradley@frontiernet.net> wrote:
><chrishornbeckremovethis@att.net> wrote:
>>Question #1: Shouldn't the issue of groove deformation during
>>recording become significant in reading the groove walls in
>>playback? And how are these related?
>
> What's the substance a record cutter cuts into? It surely doesn't
>'deform' as the stylus cuts into it the same way vinyl deforms as a
>playback stylus goes over it.

In the case of acetate being cut by a hot cutter, it deforms a _lot_.
It's gliding through it like a hot knife, both throwing out a big
swarf behind the cutter and pushing up horns on either side of the
groove.

In the case of DMM cutting into a copper blank, the deformation is
greatly reduced because the material is harder. There is no real horn,
just a lot of swarf.

It is very interesting to compare the top end on a recording cut
on a DMM disc vs. an acetate. They sound very different, and both
sound different than the original source.

Oh yes... and on cold cutting (pre-1940) where the stylus tears through
the acetate, it leaves a jagged tear at the top of the groove and very
jagged swarf. There's no horn... in fact there is stuff gouged out
where the horn would normally be.

>>Question #2: Mechanical playback averages out several orders of
>>magnitude of physical "noise", including dust, vinyl imperfections,
>>etc. Optical software averaging has got to be significant to users,
>>but also proprietary, because difficult/expensive. Artifacts?
>
> The review claims an analog signal path, which tells me that
>software is not involved here. There appear to be several lasers, and
>possibly several optical 'pickups' whose outputs can be added together
>in different proportions, depending on things such as groove angle.

Yes. And they can be adjusted in position slightly too.

>>Question #3: What would be necessary to optically scan the surface
>>to enough resolution to include all (whatever that means) original
>>information?
>
> Molecular resolution? Nanotechnology? I know, use an STM (Scanning
>Tunneling Microscope) to 'read' the groove - that would make a hellua
>record player, but playback speed would have to be much slower than
>real time, and each LP side would generate 40 gigs of information. But
>after you've done it, you can 'play' the 'virtual LP' with any shape
>and size stylus at any tracking angle.

There is an article on this in the last JAES, which I mentioned earlier.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 18, 2005 2:46:58 PM

Archived from groups: rec.audio.pro (More info?)

Edi Zubovic <edi.zubovic[rem this]@ri.t-com.hr> wrote:
>-- A nice try, funny results -- but the author admits this. But I
>remember a TV film, some 8 years ago, about the life in the USSR, from
>the common man's point of view, and a man mentioned how they would
>"dub" Western records using X-ray photo film sheets. I don't have a
>clue how that things sounded and I presume they would take a kind of
>photo of a record and a galvano process was further needed.

Was this "In Search of Melancholy Baby?"

X-ray films are very thick acetate materials, and they would not be
bad for the job.

I remember being given sheets of overhead transparency material to
practice cutting on when I was an intern. You had to be very careful
with it because it was so thin... a little bit too much L-R and you'd
go right through it. I did that for almost a week before graduating
to "yellow" reject acetates.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 18, 2005 7:16:29 PM

Archived from groups: rec.audio.pro (More info?)

<bjacoby@iwaynet.net

>
> Question #3: What would be necessary to optically scan the surface to
> enough resolution to include all (whatever that means) original
> information?
>
> A common red laser. I'm sure that should get the information to an
> accuracy sufficent to retrive the information encoded there. You
> should be able to detect all surfaces to a say a half wavelength of red
> light.


** You need far better resolution than a half wave of IR light to play a
hi-fi LP.


Here is a simple calculation:

The standard recorded level or velocity (V) on a LP is 5 cm/S peak at 1
kHz.

The formula to convert this to a peak amplitude (A) is:

A = V / (2 x pi x f) where f is the frequency

so A = 0.05 / (2 x pi x 1000) = 8 um ( 8.0 exp-6)

Allow that the noise of good vinyl may be 60 dB below this level,
then the noise amplitude is 1000 times less than this or 8 nm. ( 8.0
exp-9)

To resolve 8 nm with a scanner requires at least 3 million lines per inch.

The wavelength of the infra-red diode laser used in a CD player is 780 nm.




........... Phil
Anonymous
July 18, 2005 9:27:39 PM

Archived from groups: rec.audio.pro (More info?)

In the case of the laser groove readers does anyone know the
physics of how the laser transduces the displacement of the
groove wall to an electrical signal?


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
July 19, 2005 1:55:41 AM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey <kludge@panix.com> wrote:


> I'm not sure what you mean. The recording process _is_ groove
> deformation.
>
> A hot stylus with a facet cut in the front of it glides through
> the acetate, melting as it goes through. It plows up little
> furrows of "horn" on either side of the groove, which are sometimes
> removed.

Where does concept this come from? It certainly isn't the way most
'acetate' (nitrate) masters were cut, or the wax ones before them. The
heat is only there to polish the groove walls as they slide past the
cutter after the cutting action has taken place. the majority of the
material is removed in the form of a swarf thread.

Embossing (which is what you have described) is a very different process
from groove cutting and is not the way most recording heads worked.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Anonymous
July 19, 2005 1:55:42 AM

Archived from groups: rec.audio.pro (More info?)

Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
>Scott Dorsey <kludge@panix.com> wrote:
>> I'm not sure what you mean. The recording process _is_ groove
>> deformation.
>>
>> A hot stylus with a facet cut in the front of it glides through
>> the acetate, melting as it goes through. It plows up little
>> furrows of "horn" on either side of the groove, which are sometimes
>> removed.
>
>Where does concept this come from? It certainly isn't the way most
>'acetate' (nitrate) masters were cut, or the wax ones before them. The
>heat is only there to polish the groove walls as they slide past the
>cutter after the cutting action has taken place. the majority of the
>material is removed in the form of a swarf thread.

Most of it is removed in the swarf, but if you look at the record
surface of a recording that has not been dehorned, you'll see the
displaced material.

Many pressing plants choose to dehorn before plating. The guys at
Record Industries in Holland told me that "you must dehorn, you cannot
plate properly without it." Dehorning runs a blade across the surface
of the record and planes everything down.

On the whole, dehorning reduces the noise floor by a little bit, and
increases distortion by a little bit.

>Embossing (which is what you have described) is a very different process
>from groove cutting and is not the way most recording heads worked.

This isn't embossing an existing groove, this is a side effect of some
of the displaced material being forced sideways rather than up. It is
more of a problem with some cutting stylus configurations than others.

Oh yes, for a discussion of the general problem of groove deformation,
check out James V. White's paper in the October 1970 issue of the JAES.
(This was originally supposed to be presented as a convention paper but
was not due to the Vietnam Moratorium). The July 1966 issue has an
article from Takego Shiga, also, which has an excellent discussion of the
geometry involved.

Neither one of these has a discussion on dehorning, though, and Frayne
and Wolf only devote a couple sentences to it. So I don't have a good
reference for you right now.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 19, 2005 4:58:06 AM

Archived from groups: rec.audio.pro (More info?)

> The problem with just using a scanner, even a theoretically perfect one
> of infinite resolution, is that you're looking at the _top_ of the groove
> wall. And records aren't cut to have lowest distortion at the top of
> the groove wall, they are cut to have lowest distortion at the point where
> the groove is 1 mil wide. This means you need to get an accurate cross
> section, find the point where the stylus is supposed to rest, and estimate
> height and lateral position from that.

I would address this problem (if it were a high priority affecting my
business) by constructing a laser pickup system with the ability to set the
focus depth. Two laser beams would converge at a point inside the groove
wall, each at 45º angles to one another. One would see the vertical
component and the other would see the horizontal. From that we would derive
stereo, or differential monaural (where we could use the two tracks to
cancel random noise).
Due to the settable laser depth, the system would be able to adjust for the
cleanest part of the groove.
I know this is technically feasible, because in the late 1970s, I was doing
this sort of work for a company that designed and manufactured automatic
inspection equipment for use with web products. One time, we got an unusual
application, it was a proprietary layer from a microprocessor chip that IBM
was developing, and we needed to have the laser system (which was integrated
with optics and a photomultiplier tube + sophisticated front end
electronics) determine which holes in the dye were filled to the correct
depth with semiconductor material. I solved the problem by coming up with a
technique for reading the specular reflection intensity from the edge of the
holes.
Applying that concept as a starting point, a laser phonograph pickup could
be developed and refined.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-
Anonymous
July 19, 2005 5:20:21 AM

Archived from groups: rec.audio.pro (More info?)

On Mon, 18 Jul 2005 17:27:39 -0700, Bob Cain
<arcane@arcanemethods.com> wrote:

>In the case of the laser groove readers does anyone know the
>physics of how the laser transduces the displacement of the
>groove wall to an electrical signal?

Doppler distortion! Arf.

Chris Hornbeck
Anonymous
July 19, 2005 5:20:22 AM

Archived from groups: rec.audio.pro (More info?)

>>In the case of the laser groove readers does anyone know the
>>physics of how the laser transduces the displacement of the
>>groove wall to an electrical signal?

I'd presume they're either doing one heck of a tracking job or reading
the reflected interference pattern's peaks. The former takes a lot more
machinery, the latter takes a lot more software.
Anonymous
July 19, 2005 5:22:28 AM

Archived from groups: rec.audio.pro (More info?)

It was tried in the 80s but turned out to be more difficult than thought. I
recall that the industry was so excited with the prospect of playing ones
records and not causing groove damage! It was sad that they never made it
to market with a good unit (had a lot of problems). I heard it at a demo at
the CES in Chicago and was fascinated. It finally re-emerged now can be
purchased starting at $15,000.

http://www.elpj.com/about/

http://en.wikipedia.org/wiki/Laser_turntable


John Phillips


"Mark & Mary Ann Weiss" <mweissX294@earthlink.net> wrote in message
news:yeYCe.1023$6f.905@newsread3.news.atl.earthlink.net...
>
>> The problem with just using a scanner, even a theoretically perfect one
>> of infinite resolution, is that you're looking at the _top_ of the groove
>> wall. And records aren't cut to have lowest distortion at the top of
>> the groove wall, they are cut to have lowest distortion at the point
>> where
>> the groove is 1 mil wide. This means you need to get an accurate cross
>> section, find the point where the stylus is supposed to rest, and
>> estimate
>> height and lateral position from that.
>
> I would address this problem (if it were a high priority affecting my
> business) by constructing a laser pickup system with the ability to set
> the
> focus depth. Two laser beams would converge at a point inside the groove
> wall, each at 45º angles to one another. One would see the vertical
> component and the other would see the horizontal. From that we would
> derive
> stereo, or differential monaural (where we could use the two tracks to
> cancel random noise).
> Due to the settable laser depth, the system would be able to adjust for
> the
> cleanest part of the groove.
> I know this is technically feasible, because in the late 1970s, I was
> doing
> this sort of work for a company that designed and manufactured automatic
> inspection equipment for use with web products. One time, we got an
> unusual
> application, it was a proprietary layer from a microprocessor chip that
> IBM
> was developing, and we needed to have the laser system (which was
> integrated
> with optics and a photomultiplier tube + sophisticated front end
> electronics) determine which holes in the dye were filled to the correct
> depth with semiconductor material. I solved the problem by coming up with
> a
> technique for reading the specular reflection intensity from the edge of
> the
> holes.
> Applying that concept as a starting point, a laser phonograph pickup could
> be developed and refined.
>
>
> --
> Best Regards,
>
> Mark A. Weiss, P.E.
> www.mwcomms.com
> -
>
>
>
Anonymous
July 19, 2005 5:44:02 AM

Archived from groups: rec.audio.pro (More info?)

On Mon, 18 Jul 2005 21:22:32 -0400, Joe Kesselman
<keshlam-nospam@comcast.net> wrote:

>>>In the case of the laser groove readers does anyone know the
>>>physics of how the laser transduces the displacement of the
>>>groove wall to an electrical signal?
>
>I'd presume they're either doing one heck of a tracking job or reading
>the reflected interference pattern's peaks. The former takes a lot more
>machinery, the latter takes a lot more software.

Sorry, I'm not following you. What interference patterns? The
source is coherent, etc.

At first blush, the only thing that changes at signal rate is
time of arrival.

But then, I'm often wrong.

Chris Hornbeck
Anonymous
July 19, 2005 5:44:03 AM

Archived from groups: rec.audio.pro (More info?)

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in
message news:qhmod15m0q74b17plvbm39hb0caqbku8o1@4ax.com
> On Mon, 18 Jul 2005 21:22:32 -0400, Joe Kesselman
> <keshlam-nospam@comcast.net> wrote:
>
>>>> In the case of the laser groove readers does anyone
know the
>>>> physics of how the laser transduces the displacement of
the
>>>> groove wall to an electrical signal?
>>
>> I'd presume they're either doing one heck of a tracking
job
>> or reading the reflected interference pattern's peaks.
The
>> former takes a lot more machinery, the latter takes a lot
>> more software.

> Sorry, I'm not following you. What interference patterns?

Take a coherent source, split the beam, bounce one split
beam off a moving target, and then recombine that beam of
light with the other split of the beam, which has a constant
path length.

At the point the two beams recombine, they will either
cancel or add depending on the distance along the variable
path. As the distance over the variable path changes, there
will be a series of cancellations and additions, which can
be detected and counted. The changing distance along the
variable path can therefore be estimated from the count of
cancellations (darker) and additions (brighter).

This is used with machine tools as a high precision gauging
method.
Anonymous
July 19, 2005 12:43:26 PM

Archived from groups: rec.audio.pro (More info?)

On 18 Jul 2005 10:46:58 -0400, kludge@panix.com (Scott Dorsey) wrote:

>Edi Zubovic <edi.zubovic[rem this]@ri.t-com.hr> wrote:
>>-- A nice try, funny results -- but the author admits this. But I
>>remember a TV film, some 8 years ago, about the life in the USSR, from
>>the common man's point of view, and a man mentioned how they would
>>"dub" Western records using X-ray photo film sheets. I don't have a
>>clue how that things sounded and I presume they would take a kind of
>>photo of a record and a galvano process was further needed.
>
>Was this "In Search of Melancholy Baby?"

-- I can't remember the title but it may be. I like the title :) 

>X-ray films are very thick acetate materials, and they would not be
>bad for the job.

Oops. I must have been thinking the optical way all the time. But yes,
one could pantograph a recording to such a foil. Such copying was not
uncommon in the shellack time, the results have been inferior but
still listenable enough.

>I remember being given sheets of overhead transparency material to
>practice cutting on when I was an intern. You had to be very careful
>with it because it was so thin... a little bit too much L-R and you'd
>go right through it. I did that for almost a week before graduating
>to "yellow" reject acetates.
>--scott
-- Yes, that must have been a right practice indeed!

Edi Zubovic, Crikvenica, Croatia
Anonymous
July 19, 2005 1:31:28 PM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey <kludge@panix.com> wrote:

> Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
> >Scott Dorsey <kludge@panix.com> wrote:
> >> I'm not sure what you mean. The recording process _is_ groove
> >> deformation.
> >>
> >> A hot stylus with a facet cut in the front of it glides through
> >> the acetate, melting as it goes through. It plows up little
> >> furrows of "horn" on either side of the groove, which are sometimes
> >> removed.
> >
> >Where does concept this come from? It certainly isn't the way most
> >'acetate' (nitrate) masters were cut, or the wax ones before them. The
> >heat is only there to polish the groove walls as they slide past the
> >cutter after the cutting action has taken place. the majority of the
> >material is removed in the form of a swarf thread.
>
> Most of it is removed in the swarf, but if you look at the record
> surface of a recording that has not been dehorned, you'll see the
> displaced material.

My apologies. I had read your provious posting as meaning that the
removed material *all* went into the horns (you didn't mention the
swarf) - that was why I queried which you were talking about: cutting or
embossing.


> This isn't embossing an existing groove,...

Was that system ever use in any quantity in the US? It was almost
unknown in the UK.

I have just been asked to transcribe a disc from the US, which looks as
though it might have been embossed on a pre-grooved blank. It has a
*noise-to-signal* ratio, the modulation is barely audible and it is
badly distorted on peaks.

Was this the usual result to be expected from a pre-grooved embossing
system? - or has someone tried to use the wrong cutterhead to make the
disc - or perhaps this copy has been played with a heavy acoustic
gramophone soundbox and had the modulation wiped off it (the material is
filled vinyl).

Time to get out the microscope I think.....


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Anonymous
July 19, 2005 1:31:29 PM

Archived from groups: rec.audio.pro (More info?)

Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
>Scott Dorsey <kludge@panix.com> wrote:
>
>> This isn't embossing an existing groove,...
>
>Was that system ever use in any quantity in the US? It was almost
>unknown in the UK.

It was used in a couple dictation machines, and in some home recording
machines. I am told there were some coin-operated automatic recording
booths during WWII that servicemen could use to record a message and
mail them home, and that these used such a format but I have never seen
them.

Many of the belt-type dictation machines used embossing.
>
>I have just been asked to transcribe a disc from the US, which looks as
>though it might have been embossed on a pre-grooved blank. It has a
>*noise-to-signal* ratio, the modulation is barely audible and it is
>badly distorted on peaks.
>
>Was this the usual result to be expected from a pre-grooved embossing
>system? - or has someone tried to use the wrong cutterhead to make the
>disc - or perhaps this copy has been played with a heavy acoustic
>gramophone soundbox and had the modulation wiped off it (the material is
>filled vinyl).
>
>Time to get out the microscope I think.....

If it's embossed, you will see a straight groove that has no lateral
modulation at all, with the top pressed down. The normal way to play
embossed discs back is by using a very large ball-shaped stylus which
rides up and down on the top of the groove.

Expert Stylus in Surrey makes the things up on request.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 19, 2005 2:52:50 PM

Archived from groups: rec.audio.pro (More info?)

On 18 Jul 2005 18:40:44 -0400, kludge@panix.com (Scott Dorsey) wrote:

>Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
>>Scott Dorsey <kludge@panix.com> wrote:
>>> I'm not sure what you mean. The recording process _is_ groove
>>> deformation.
>>>
>>> A hot stylus with a facet cut in the front of it glides through
>>> the acetate, melting as it goes through. It plows up little
>>> furrows of "horn" on either side of the groove, which are sometimes
>>> removed.
>>
>>Where does concept this come from? It certainly isn't the way most
>>'acetate' (nitrate) masters were cut, or the wax ones before them. The
>>heat is only there to polish the groove walls as they slide past the
>>cutter after the cutting action has taken place. the majority of the
>>material is removed in the form of a swarf thread.
>
>Most of it is removed in the swarf, but if you look at the record
>surface of a recording that has not been dehorned, you'll see the
>displaced material.
>
>Many pressing plants choose to dehorn before plating. The guys at
>Record Industries in Holland told me that "you must dehorn, you cannot
>plate properly without it." Dehorning runs a blade across the surface
>of the record and planes everything down.
>
---------------8<------------------------------------

-- Are these "horns" responsible for so-called "nonfills", where when
stamper splats, the hot vinyl misses a portion of record? -- Here or
there I've encountered such records (singles, mainly) and there is a
massive distortion at such areas. They can be clearly seen.

Edi Zubovic, Crikvenica, Croatia
Anonymous
July 19, 2005 2:52:51 PM

Archived from groups: rec.audio.pro (More info?)

Edi Zubovic <edi.zubovic[rem this]@ri.t-com.hr> wrote:
>
>-- Are these "horns" responsible for so-called "nonfills", where when
>stamper splats, the hot vinyl misses a portion of record? -- Here or
>there I've encountered such records (singles, mainly) and there is a
>massive distortion at such areas. They can be clearly seen.

No, that's a pressing problem rather than a cutting problem. That is
usually caused by an uneven vinyl mix and/or someone running the press
too fast.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 19, 2005 3:42:07 PM

Archived from groups: rec.audio.pro (More info?)

Joe Kesselman wrote:
>>> In the case of the laser groove readers does anyone know the physics
>>> of how the laser transduces the displacement of the groove wall to an
>>> electrical signal?
>
>
> I'd presume they're either doing one heck of a tracking job

Yeah, I can't see what would be tracked even. The walls are
independantly moving normal to lines at 45 degrees to the
vertical.

> or reading
> the reflected interference pattern's peaks. The former takes a lot more
> machinery, the latter takes a lot more software.

And a high resolution interferometer! Noisy beasts, those.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
July 19, 2005 3:46:46 PM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger wrote:

> Take a coherent source, split the beam, bounce one split
> beam off a moving target, and then recombine that beam of
> light with the other split of the beam, which has a constant
> path length.

Yeah, a laser interferometer.

>
> At the point the two beams recombine, they will either
> cancel or add depending on the distance along the variable
> path. As the distance over the variable path changes, there
> will be a series of cancellations and additions, which can
> be detected and counted. The changing distance along the
> variable path can therefore be estimated from the count of
> cancellations (darker) and additions (brighter).

This would require light with a wavelength _much_ smaller
than the excursion of the groove wall. I can't remember
offhand what the wavlength of practical lasers for this app
would be but I think we are talking here about measuring
small fractions of a cycle phase difference rather than
multiples.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
July 19, 2005 4:23:21 PM

Archived from groups: rec.audio.pro (More info?)

"Mark & Mary Ann Weiss"
>
>
> I would address this problem (if it were a high priority affecting my
> business) by constructing a laser pickup system with the ability to set
> the
> focus depth. Two laser beams would converge at a point inside the groove
> wall, each at 45º angles to one another. One would see the vertical
> component and the other would see the horizontal. From that we would
> derive
> stereo, or differential monaural (where we could use the two tracks to
> cancel random noise).


** Your noise cancelling idea sounds rather optimistic !

Lateral modulation of a stereo groove is the mono or L+R component.

Vertical movement is the difference or L - R component.

So, for a mono (ie lateral only) recording, L - R = 0 and there is no
vertical modulation.


** Now the important bits:

A signal that appears in one channel only, modulates only one side of the
groove.

Surface noise is largely random on EACH side of the groove - when a mono
recording played on a stereo system, the surface noise is in stereo !!



.......... Phil
Anonymous
July 19, 2005 4:23:22 PM

Archived from groups: rec.audio.pro (More info?)

On Tue, 19 Jul 2005 12:23:21 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

>
>"Mark & Mary Ann Weiss"
>>
>>
>> I would address this problem (if it were a high priority affecting my
>> business) by constructing a laser pickup system with the ability to set
>> the
>> focus depth. Two laser beams would converge at a point inside the groove
>> wall, each at 45? angles to one another. One would see the vertical
>> component and the other would see the horizontal. From that we would
>> derive
>> stereo, or differential monaural (where we could use the two tracks to
>> cancel random noise).
>
>
>** Your noise cancelling idea sounds rather optimistic !

And it does work to an extent!

>Lateral modulation of a stereo groove is the mono or L+R component.
>
>Vertical movement is the difference or L - R component.
>
>So, for a mono (ie lateral only) recording, L - R = 0 and there is no
>vertical modulation.
>
>
>** Now the important bits:
>
>A signal that appears in one channel only, modulates only one side of the
>groove.
>
>Surface noise is largely random on EACH side of the groove - when a mono
>recording played on a stereo system, the surface noise is in stereo !!

.... which can be partially cancelled and the scratch peaks can be
reduced or even cancelled out. When you see a L and R scratch in the
displayed waveform, it's more or less inverted. Now this is why all my
record transfers are best made with a stereo pickup. You can invert,
channel replace the portion, use the inner grove information only etc.
Of course, this applies to prominent impulse noise -- surface noise is
random and it can not fall into the category. Generally, at a mono
record reproduced stereo, what is in the center that you'll get after
inverting. The side information will be affected more or less,
depending of coherency.
>......... Phil

Edi Zubovic, Crikvenica, Croatia
Anonymous
July 19, 2005 7:09:42 PM

Archived from groups: rec.audio.pro (More info?)

"Bob Cain" <arcane@arcanemethods.com> wrote in message
news:D bjhji02mck@enews1.newsguy.com
> Joe Kesselman wrote:
>>>> In the case of the laser groove readers does anyone
know
>>>> the physics of how the laser transduces the
displacement of
>>>> the groove wall to an electrical signal?
>>
>>
>> I'd presume they're either doing one heck of a tracking
job

> Yeah, I can't see what would be tracked even. The walls
are
> independantly moving normal to lines at 45 degrees to the
> vertical.

I'd guess that they use two separate crossed beams oriented
45 degrees from vertical. The basic control law is keep the
distance from the light sensors to each side of the groove
the same after low-pass filtering. The AC signal on each
servo feedback line is basically the groove modulation.
Anonymous
July 19, 2005 8:34:07 PM

Archived from groups: rec.audio.pro (More info?)

"Bob Cain" <arcane@arcanemethods.com> wrote in message
news:D bjhsa02mnk@enews1.newsguy.com
> Arny Krueger wrote:
>
>> Take a coherent source, split the beam, bounce one split
>> beam off a moving target, and then recombine that beam of
>> light with the other split of the beam, which has a
constant
>> path length.
>
> Yeah, a laser interferometer.
>
>>
>> At the point the two beams recombine, they will either
>> cancel or add depending on the distance along the
variable
>> path. As the distance over the variable path changes,
there
>> will be a series of cancellations and additions, which
can
>> be detected and counted. The changing distance along the
>> variable path can therefore be estimated from the count
of
>> cancellations (darker) and additions (brighter).
>
> This would require light with a wavelength _much_ smaller
> than the excursion of the groove wall.

Inferiometry works for distances less than a wavelength. The
measurement is then based on shades of grey.

http://www.msi-viking.com/laser_micrometer/

says that they measure with resolution of 0.00001mm which is
10 nanometers.

Phil Allison calculated the peak amplitude of a LP groove at
1 KHz to be 8 um or 8000 nanometers.

So, a inferometry-based phono pickup based on this
technology could easily have almost 60 dB dynamic range
before any SNR benefits due to RIAA equalization. I'm
putting pieces together really roughly here, but it seems
feasible.

> I can't remember
> offhand what the wavlength of practical lasers for this
app
> would be but I think we are talking here about measuring
> small fractions of a cycle phase difference rather than
> multiples.

Yes, and that's possible as well. For example Loran was
based on radio wave inferometry within fractions of a cycle,
with a modulating frequency of 30 Hz. All the actual
measurments were based within 1/4 of a 30 Hz RF wavelength
(about 1500 miles) as I recall.
Anonymous
July 19, 2005 10:40:20 PM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey <kludge@panix.com> wrote:

> Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
> >Scott Dorsey <kludge@panix.com> wrote:
> >
> >> This isn't embossing an existing groove,...
> >
> >Was that system ever use in any quantity in the US? It was almost
> >unknown in the UK.
>
> It was used in a couple dictation machines, and in some home recording
> machines. I am told there were some coin-operated automatic recording
> booths during WWII that servicemen could use to record a message and
> mail them home, and that these used such a format but I have never seen
> them.

I think it was me who told you in an earlier post. I specialise in
playing back weird formats and have had dozens of embossed aluminium
discs sent my way. (I have a copy of the patent for the machine that
made them).

I was wondering if perhaps the pre-grooved vinyl type was more popular
in the US, since the only commercial example I have ever seen came from
there.



> >
> >I have just been asked to transcribe a disc from the US, which looks as
> >though it might have been embossed on a pre-grooved blank. It has a
> >*noise-to-signal* ratio, the modulation is barely audible and it is
> >badly distorted on peaks.
> >
> >Was this the usual result to be expected from a pre-grooved embossing
> >system? - or has someone tried to use the wrong cutterhead to make the
> >disc - or perhaps this copy has been played with a heavy acoustic
> >gramophone soundbox and had the modulation wiped off it (the material is
> >filled vinyl).
> >
> >Time to get out the microscope I think.....
>
> If it's embossed, you will see a straight groove that has no lateral
> modulation at all, with the top pressed down. The normal way to play
> embossed discs back is by using a very large ball-shaped stylus which
> rides up and down on the top of the groove.
>
> Expert Stylus in Surrey makes the things up on request.

I use their styli, but even the largest size registered virtually no
modulation on this particular disc (which, incidentally, arrived in two
pieces). I tried 'hill-and-dale' as well as lateral, just in case I was
dealing with a really strange format.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Anonymous
July 19, 2005 10:40:21 PM

Archived from groups: rec.audio.pro (More info?)

Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
>>
>> If it's embossed, you will see a straight groove that has no lateral
>> modulation at all, with the top pressed down. The normal way to play
>> embossed discs back is by using a very large ball-shaped stylus which
>> rides up and down on the top of the groove.
>>
>> Expert Stylus in Surrey makes the things up on request.
>
>I use their styli, but even the largest size registered virtually no
>modulation on this particular disc (which, incidentally, arrived in two
>pieces). I tried 'hill-and-dale' as well as lateral, just in case I was
>dealing with a really strange format.

These aren't really styli, just huge ball-shaped things perhaps
as much as 50 mil in diameter. They ride on top of the groove rather
than in it.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 20, 2005 12:15:08 AM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger wrote:


> Inferiometry works for distances less than a wavelength. The
> measurement is then based on shades of grey.
>
> http://www.msi-viking.com/laser_micrometer/

I wonder what the response of that is at 20 kHz. :-)

I have a feeling this device is for static measurement which
allows for all kinds of noise immunity.

> says that they measure with resolution of 0.00001mm which is
> 10 nanometers.
>
> Phil Allison calculated the peak amplitude of a LP groove at
> 1 KHz to be 8 um or 8000 nanometers.

Isn't it a tenth that at 10 kHz?

> So, a inferometry-based phono pickup based on this
> technology could easily have almost 60 dB dynamic range
> before any SNR benefits due to RIAA equalization. I'm
> putting pieces together really roughly here, but it seems
> feasible.

What is it you've said is the dynamic range with a magnetic
pickup?


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
July 20, 2005 12:17:08 AM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger wrote:

> I'd guess that they use two separate crossed beams oriented
> 45 degrees from vertical. The basic control law is keep the
> distance from the light sensors to each side of the groove
> the same after low-pass filtering.

20 kHz lowpass?

> The AC signal on each
> servo feedback line is basically the groove modulation.

Interesting approach.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
July 20, 2005 1:19:02 AM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey <kludge@panix.com> wrote:

> Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
> >>
> >> If it's embossed, you will see a straight groove that has no lateral
> >> modulation at all, with the top pressed down. The normal way to play
> >> embossed discs back is by using a very large ball-shaped stylus which
> >> rides up and down on the top of the groove.
> >>
> >> Expert Stylus in Surrey makes the things up on request.
> >
> >I use their styli, but even the largest size registered virtually no
> >modulation on this particular disc (which, incidentally, arrived in two
> >pieces). I tried 'hill-and-dale' as well as lateral, just in case I was
> >dealing with a really strange format.
>
> These aren't really styli, just huge ball-shaped things perhaps
> as much as 50 mil in diameter. They ride on top of the groove rather
> than in it.

Yes, I know them. They are primarily intended for playing two-minute
wax cylinders.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Anonymous
July 20, 2005 1:19:03 AM

Archived from groups: rec.audio.pro (More info?)

Adrian Tuddenham <poppy.uk@ukonline.invalid.invalid> wrote:
>Yes, I know them. They are primarily intended for playing two-minute
>wax cylinders.

Yes! Those things! There's a word for them that I can't remember...
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 20, 2005 1:51:14 AM

Archived from groups: rec.audio.pro (More info?)

On Tue, 19 Jul 2005 15:09:42 -0400, "Arny Krueger" <arnyk@hotpop.com>
wrote:

>I'd guess that they use two separate crossed beams oriented
>45 degrees from vertical. The basic control law is keep the
>distance from the light sensors to each side of the groove
>the same after low-pass filtering. The AC signal on each
>servo feedback line is basically the groove modulation.

Does this imply that the moving mirrors of your interferometer
wiggle along with the groove walls? If so, it would go a
long way toward explaining their published bandwidth limitations.

Thanks,

Chris Hornbeck
Anonymous
July 20, 2005 1:51:15 AM

Archived from groups: rec.audio.pro (More info?)

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in
message news:c8tqd152hi3i9257bjmn5j56pt827s63c2@4ax.com
> On Tue, 19 Jul 2005 15:09:42 -0400, "Arny Krueger"
> <arnyk@hotpop.com> wrote:
>
>> I'd guess that they use two separate crossed beams
oriented
>> 45 degrees from vertical. The basic control law is keep
the
>> distance from the light sensors to each side of the
groove
>> the same after low-pass filtering. The AC signal on each
>> servo feedback line is basically the groove modulation.
>
> Does this imply that the moving mirrors of your
interferometer
> wiggle along with the groove walls? If so, it would go a
> long way toward explaining their published bandwidth
> limitations.

I'm under the impression that the vinyl itself is reflective
enough.
Anonymous
July 20, 2005 3:14:34 AM

Archived from groups: rec.audio.pro (More info?)

On Tue, 19 Jul 2005 18:59:28 -0400, "Arny Krueger" <arnyk@hotpop.com>
wrote:

>> Does this imply that the moving mirrors of your
>interferometer
>> wiggle along with the groove walls? If so, it would go a
>> long way toward explaining their published bandwidth
>> limitations.
>
>I'm under the impression that the vinyl itself is reflective
>enough.

Now I'm really lost. My (sorry, unstated) assumption was that
the lasers would ride along on a little sled, analogous to
a phono cartridge in relative geometry to the disk surface.

I'd also assumed that illumination spot size was not significant,
and that the receiver's optics would have to determine focus,
and therefore "read" (past tense) groove wall area.

ELP's promotional material is intiguing but vague, and I
haven't a clue. What an exciting combination, after a
hard hot day's slog!

Thanks for any thoughts,

Chris Hornbeck
Anonymous
July 20, 2005 3:14:35 AM

Archived from groups: rec.audio.pro (More info?)

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in
message news:ll1rd1pctdffeh502s3pmjcf2srd1f6pav@4ax.com
> On Tue, 19 Jul 2005 18:59:28 -0400, "Arny Krueger"
> <arnyk@hotpop.com> wrote:
>
>>> Does this imply that the moving mirrors of your
>> interferometer
>>> wiggle along with the groove walls? If so, it would go a
>>> long way toward explaining their published bandwidth
>>> limitations.
>>
>> I'm under the impression that the vinyl itself is
reflective
>> enough.
>
> Now I'm really lost. My (sorry, unstated) assumption was
that
> the lasers would ride along on a little sled, analogous to
> a phono cartridge in relative geometry to the disk
surface.

I don't think so. Note all the comments about the problems
due to the laser players having no tip mass to clean out and
properly deform the groove.

> I'd also assumed that illumination spot size was not
> significant, and that the receiver's optics would have to
determine focus,
> and therefore "read" (past tense) groove wall area.

I think the focus is done the old fashioned way - by flying
the optics a given distance from the grooves in the LP.

> ELP's promotional material is intiguing but vague, and I
> haven't a clue. What an exciting combination, after a
> hard hot day's slog!

My only advantage over the average RAP bear is that I've
actually seen and heard an ELP or whatever they call it this
week live, up front and personal at HE2005. Its handlers
weren't very informative.
!