Shame on Sound on Sound

[Jay Levitt]

I was just reading my November issue, and noticed this whopper from
technical editor Hugh Robjohns:

"The CD burner creates small bumps in the playing surface of the CD-R
that the CD player can then detect. The spacing between each bump is
critical to being able to detect and decode the data signal. But more
importantly, the rising and falling edge (the beginning and end) of each
bump is also critical, and this is the aspect that is most affected by
different combinations of burn speed, disc media and the state of the
laser."

Oh, SOS...

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

[Geoff Wood]

"Jay Levitt" > wrote in message
...
>I was just reading my November issue, and noticed this whopper from
> technical editor Hugh Robjohns:
>
> "The CD burner creates small bumps in the playing surface of the CD-R
> that the CD player can then detect. The spacing between each bump is
> critical to being able to detect and decode the data signal. But more
> importantly, the rising and falling edge (the beginning and end) of each
> bump is also critical, and this is the aspect that is most affected by
> different combinations of burn speed, disc media and the state of the
> laser."
>
> Oh, SOS...

Maybe suffering from trying to 'talk down to the layman' where this was not
necessary, and in fact quite counter-productive...

geoff

[Geoff Wood]

"Jay Levitt" > wrote in message
...
>I was just reading my November issue, and noticed this whopper from
> technical editor Hugh Robjohns:
>
> "The CD burner creates small bumps in the playing surface of the CD-R
> that the CD player can then detect. The spacing between each bump is
> critical to being able to detect and decode the data signal. But more
> importantly, the rising and falling edge (the beginning and end) of each
> bump is also critical, and this is the aspect that is most affected by
> different combinations of burn speed, disc media and the state of the
> laser."
>
> Oh, SOS...

Maybe suffering from trying to 'talk down to the layman' where this was not
necessary, and in fact quite counter-productive...

geoff

[Mike Rocha]

"Geoff Wood" -nospam> wrote in message
...
>
> "Jay Levitt" > wrote in message
> ...
>>I was just reading my November issue, and noticed this whopper from
>> technical editor Hugh Robjohns:
>>
>> "The CD burner creates small bumps in the playing surface of the CD-R
>> that the CD player can then detect. The spacing between each bump is
>> critical to being able to detect and decode the data signal. But more
>> importantly, the rising and falling edge (the beginning and end) of each
>> bump is also critical, and this is the aspect that is most affected by
>> different combinations of burn speed, disc media and the state of the
>> laser."
>>
>> Oh, SOS...
>
> Maybe suffering from trying to 'talk down to the layman' where this was
> not necessary, and in fact quite counter-productive...
>
> geoff
>
Care to briefly correct the inaccuracy in that statement? I read it in the
same issue and it sounded a little odd at the time but i didn't think much
of it. Don't have too much background on that topic.

Thanks

Roach

[Mike Rocha]

"Geoff Wood" -nospam> wrote in message
...
>
> "Jay Levitt" > wrote in message
> ...
>>I was just reading my November issue, and noticed this whopper from
>> technical editor Hugh Robjohns:
>>
>> "The CD burner creates small bumps in the playing surface of the CD-R
>> that the CD player can then detect. The spacing between each bump is
>> critical to being able to detect and decode the data signal. But more
>> importantly, the rising and falling edge (the beginning and end) of each
>> bump is also critical, and this is the aspect that is most affected by
>> different combinations of burn speed, disc media and the state of the
>> laser."
>>
>> Oh, SOS...
>
> Maybe suffering from trying to 'talk down to the layman' where this was
> not necessary, and in fact quite counter-productive...
>
> geoff
>
Care to briefly correct the inaccuracy in that statement? I read it in the
same issue and it sounded a little odd at the time but i didn't think much
of it. Don't have too much background on that topic.

Thanks

Roach

[Jay Levitt]

In article >,
says...
> >>I was just reading my November issue, and noticed this whopper from
> >> technical editor Hugh Robjohns:
> >>
> >> "The CD burner creates small bumps in the playing surface of the CD-R
> >> that the CD player can then detect. The spacing between each bump is
> >> critical to being able to detect and decode the data signal. But more
> >> importantly, the rising and falling edge (the beginning and end) of each
> >> bump is also critical, and this is the aspect that is most affected by
> >> different combinations of burn speed, disc media and the state of the
> >> laser."
> >>
> >> Oh, SOS...
> >
> Care to briefly correct the inaccuracy in that statement? I read it in the
> same issue and it sounded a little odd at the time but i didn't think much
> of it. Don't have too much background on that topic.

Pressed CDs have pits and lands ("bumps"). Burned CDs have dye that is
turned either opaque or transparent by the laser (I forget which state
is "default"). There are no bumps.

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

[Jay Levitt]

In article >,
says...
> >>I was just reading my November issue, and noticed this whopper from
> >> technical editor Hugh Robjohns:
> >>
> >> "The CD burner creates small bumps in the playing surface of the CD-R
> >> that the CD player can then detect. The spacing between each bump is
> >> critical to being able to detect and decode the data signal. But more
> >> importantly, the rising and falling edge (the beginning and end) of each
> >> bump is also critical, and this is the aspect that is most affected by
> >> different combinations of burn speed, disc media and the state of the
> >> laser."
> >>
> >> Oh, SOS...
> >
> Care to briefly correct the inaccuracy in that statement? I read it in the
> same issue and it sounded a little odd at the time but i didn't think much
> of it. Don't have too much background on that topic.

Pressed CDs have pits and lands ("bumps"). Burned CDs have dye that is
turned either opaque or transparent by the laser (I forget which state
is "default"). There are no bumps.

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

[David Morgan \(MAMS\)]

"Jay Levitt" > wrote in message ...
> In article >,
> says...
> > >>I was just reading my November issue, and noticed this whopper from
> > >> technical editor Hugh Robjohns:
> > >>
> > >> "The CD burner creates small bumps in the playing surface of the CD-R
> > >> that the CD player can then detect. The spacing between each bump is
> > >> critical to being able to detect and decode the data signal. But more
> > >> importantly, the rising and falling edge (the beginning and end) of each
> > >> bump is also critical, and this is the aspect that is most affected by
> > >> different combinations of burn speed, disc media and the state of the
> > >> laser."
> > >>
> > >> Oh, SOS...
> > >
> > Care to briefly correct the inaccuracy in that statement? I read it in the
> > same issue and it sounded a little odd at the time but i didn't think much
> > of it. Don't have too much background on that topic.
>
> Pressed CDs have pits and lands ("bumps"). Burned CDs have dye that is
> turned either opaque or transparent by the laser (I forget which state
> is "default"). There are no bumps.

Other than having pits in lieu of 'bumps', I was of a mind that the causes for
inaccuracy of the pit burn were pretty much as described. It *was* a rather
large error to describe the read surface completely ass-backwards.

--
David Morgan (MAMS)
http://www.m-a-m-s.com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.artisan-recordingstudio.com

[David Morgan \(MAMS\)]

"Jay Levitt" > wrote in message ...
> In article >,
> says...
> > >>I was just reading my November issue, and noticed this whopper from
> > >> technical editor Hugh Robjohns:
> > >>
> > >> "The CD burner creates small bumps in the playing surface of the CD-R
> > >> that the CD player can then detect. The spacing between each bump is
> > >> critical to being able to detect and decode the data signal. But more
> > >> importantly, the rising and falling edge (the beginning and end) of each
> > >> bump is also critical, and this is the aspect that is most affected by
> > >> different combinations of burn speed, disc media and the state of the
> > >> laser."
> > >>
> > >> Oh, SOS...
> > >
> > Care to briefly correct the inaccuracy in that statement? I read it in the
> > same issue and it sounded a little odd at the time but i didn't think much
> > of it. Don't have too much background on that topic.
>
> Pressed CDs have pits and lands ("bumps"). Burned CDs have dye that is
> turned either opaque or transparent by the laser (I forget which state
> is "default"). There are no bumps.

Other than having pits in lieu of 'bumps', I was of a mind that the causes for
inaccuracy of the pit burn were pretty much as described. It *was* a rather
large error to describe the read surface completely ass-backwards.

--
David Morgan (MAMS)
http://www.m-a-m-s.com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.artisan-recordingstudio.com

[Geoff Wood]

"Mike Rocha" > wrote in message

> Care to briefly correct the inaccuracy in that statement? I read it in the
> same issue and it sounded a little odd at the time but i didn't think much
> of it. Don't have too much background on that topic.

There are no bumps in a CD-R. The changes are in the optical properties in
a film of laser-sensitive dye. 'Bumps' (better known as 'pits') are unique
to stamped CDs.

geoff

[Geoff Wood]

"Mike Rocha" > wrote in message

> Care to briefly correct the inaccuracy in that statement? I read it in the
> same issue and it sounded a little odd at the time but i didn't think much
> of it. Don't have too much background on that topic.

There are no bumps in a CD-R. The changes are in the optical properties in
a film of laser-sensitive dye. 'Bumps' (better known as 'pits') are unique
to stamped CDs.

geoff

[Mike Rivers]

In article <DKNld.2969$J55.888@trnddc06> writes:

> Other than having pits in lieu of 'bumps', I was of a mind that the causes for
> inaccuracy of the pit burn were pretty much as described. It *was* a rather
> large error to describe the read surface completely ass-backwards.

Can't bumps go down, too? Or can't a "bump" be a change in reflectivity?
Does it have to be a physical increase in the height of the surface of the disk?

It was an explanation of the principle of how a CD gets read, not a discourse
on how the disks are manufactured. How many readers do you think care
whether the bumps go up or down anyway? Bumps is bumps, and Sound on
Sound ain't the AES Journal, or even Scientific American.

--
I'm really Mike Rivers )
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

[Mike Rivers]

In article <DKNld.2969$J55.888@trnddc06> writes:

> Other than having pits in lieu of 'bumps', I was of a mind that the causes for
> inaccuracy of the pit burn were pretty much as described. It *was* a rather
> large error to describe the read surface completely ass-backwards.

Can't bumps go down, too? Or can't a "bump" be a change in reflectivity?
Does it have to be a physical increase in the height of the surface of the disk?

It was an explanation of the principle of how a CD gets read, not a discourse
on how the disks are manufactured. How many readers do you think care
whether the bumps go up or down anyway? Bumps is bumps, and Sound on
Sound ain't the AES Journal, or even Scientific American.

--
I'm really Mike Rivers )
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

[Jay Levitt]

In article <znr1100463138k@trad>, says...
> Or can't a "bump" be a change in reflectivity?

I admit, I have tripped over bumps of that very type.

> Does it have to be a physical increase in the height of the surface of the disk?
>

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

[Jay Levitt]

In article <znr1100463138k@trad>, says...
> Or can't a "bump" be a change in reflectivity?

I admit, I have tripped over bumps of that very type.

> Does it have to be a physical increase in the height of the surface of the disk?
>

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

[Geoff Wood]

"Mike Rivers" > wrote in message
news:znr1100463138k@trad...
>
> In article <DKNld.2969$J55.888@trnddc06> writes:
>
>> Other than having pits in lieu of 'bumps', I was of a mind that the
>> causes for
>> inaccuracy of the pit burn were pretty much as described. It *was* a
>> rather
>> large error to describe the read surface completely ass-backwards.
>
> Can't bumps go down, too? Or can't a "bump" be a change in reflectivity?
> Does it have to be a physical increase in the height of the surface of the
> disk?
>
> It was an explanation of the principle of how a CD gets read, not a
> discourse
> on how the disks are manufactured. How many readers do you think care
> whether the bumps go up or down anyway? Bumps is bumps, and Sound on
> Sound ain't the AES Journal, or even Scientific American.

Try driving over a bump in your car, then try again over a pit.

There are NO bumps (or pits) in CD-Rs at all. Not upwards, downwards, or
sideways.

Sound On Sound is generally very concise.

geoff

[Geoff Wood]

"Mike Rivers" > wrote in message
news:znr1100463138k@trad...
>
> In article <DKNld.2969$J55.888@trnddc06> writes:
>
>> Other than having pits in lieu of 'bumps', I was of a mind that the
>> causes for
>> inaccuracy of the pit burn were pretty much as described. It *was* a
>> rather
>> large error to describe the read surface completely ass-backwards.
>
> Can't bumps go down, too? Or can't a "bump" be a change in reflectivity?
> Does it have to be a physical increase in the height of the surface of the
> disk?
>
> It was an explanation of the principle of how a CD gets read, not a
> discourse
> on how the disks are manufactured. How many readers do you think care
> whether the bumps go up or down anyway? Bumps is bumps, and Sound on
> Sound ain't the AES Journal, or even Scientific American.

Try driving over a bump in your car, then try again over a pit.

There are NO bumps (or pits) in CD-Rs at all. Not upwards, downwards, or
sideways.

Sound On Sound is generally very concise.

geoff

[Drily Lit Raga]

"Geoff Wood" -nospam> wrote in
:

>
> "Mike Rocha" > wrote in message
>
>> Care to briefly correct the inaccuracy in that statement? I read it
>> in the same issue and it sounded a little odd at the time but i
>> didn't think much of it. Don't have too much background on that
>> topic.
>
> There are no bumps in a CD-R. The changes are in the optical
> properties in a film of laser-sensitive dye. 'Bumps' (better known as
> 'pits') are unique to stamped CDs.
>
> geoff

You have ra-ceived a beump, one could get a concussion from such a beump.

- Inspector Clouseau

[Drily Lit Raga]

"Geoff Wood" -nospam> wrote in
:

>
> "Mike Rocha" > wrote in message
>
>> Care to briefly correct the inaccuracy in that statement? I read it
>> in the same issue and it sounded a little odd at the time but i
>> didn't think much of it. Don't have too much background on that
>> topic.
>
> There are no bumps in a CD-R. The changes are in the optical
> properties in a film of laser-sensitive dye. 'Bumps' (better known as
> 'pits') are unique to stamped CDs.
>
> geoff

You have ra-ceived a beump, one could get a concussion from such a beump.

- Inspector Clouseau

[Ty Ford]

On Mon, 15 Nov 2004 00:35:54 -0500, Drily Lit Raga wrote
(in article >):

> "Geoff Wood" -nospam> wrote in
> :
>
>>
>> "Mike Rocha" > wrote in message
>>
>>> Care to briefly correct the inaccuracy in that statement? I read it
>>> in the same issue and it sounded a little odd at the time but i
>>> didn't think much of it. Don't have too much background on that
>>> topic.
>>
>> There are no bumps in a CD-R. The changes are in the optical
>> properties in a film of laser-sensitive dye. 'Bumps' (better known as
>> 'pits') are unique to stamped CDs.
>>
>> geoff
>
> You have ra-ceived a beump, one could get a concussion from such a beump.
>
> - Inspector Clouseau

Brain Fart; happens now and then.

Ty Ford



-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

[Ty Ford]

On Mon, 15 Nov 2004 00:35:54 -0500, Drily Lit Raga wrote
(in article >):

> "Geoff Wood" -nospam> wrote in
> :
>
>>
>> "Mike Rocha" > wrote in message
>>
>>> Care to briefly correct the inaccuracy in that statement? I read it
>>> in the same issue and it sounded a little odd at the time but i
>>> didn't think much of it. Don't have too much background on that
>>> topic.
>>
>> There are no bumps in a CD-R. The changes are in the optical
>> properties in a film of laser-sensitive dye. 'Bumps' (better known as
>> 'pits') are unique to stamped CDs.
>>
>> geoff
>
> You have ra-ceived a beump, one could get a concussion from such a beump.
>
> - Inspector Clouseau

Brain Fart; happens now and then.

Ty Ford



-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

[Mike Rivers]

In article > writes:

> Brain Fart; happens now and then.

Was the path of that fart from the brain to the asshole or the asshole
to the brain?

Makes a difference whether it's a pit or a bump.



--
I'm really Mike Rivers )
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

[Mike Rivers]

In article > writes:

> Brain Fart; happens now and then.

Was the path of that fart from the brain to the asshole or the asshole
to the brain?

Makes a difference whether it's a pit or a bump.



--
I'm really Mike Rivers )
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

[Hugh Robjohns, Technical Editor SOS]

I am impressed that you all take such stock of Sound On Sound that a
silly typo slip like this causes such consternation. It keeps us all
on our toes -- and rightly so.

I'm afraid this was a simple case of brain fade (or brain fart -- I
like that... very apt!).

It is indeed the case that the CD-R burning process uses a relatively
high powered laser to cause the organic dye layer in the disc to
darken when heated. Thus the affected sections of the organic layer
allows less light through (and back) from the reflective layer below
when read by a standard power laser. The opto-receiver therefore sees
a varying intensity of reflected laser light according to the number
and spacing of the 'burned' areas of the disc, and this represents the
binary channel code recorded to the disc.

'Bumps' are indeed the restricted to pressed CDs, and produce the
required varying intensity of reflected light through phase
cancellation of the light reflected from the tops of the bumps and the
surrounding lands.

Apologies for any confusion caused in this detail of that particular
Q&A.

Kindest regards to all our readers,

hugh

[Hugh Robjohns, Technical Editor SOS]

I am impressed that you all take such stock of Sound On Sound that a
silly typo slip like this causes such consternation. It keeps us all
on our toes -- and rightly so.

I'm afraid this was a simple case of brain fade (or brain fart -- I
like that... very apt!).

It is indeed the case that the CD-R burning process uses a relatively
high powered laser to cause the organic dye layer in the disc to
darken when heated. Thus the affected sections of the organic layer
allows less light through (and back) from the reflective layer below
when read by a standard power laser. The opto-receiver therefore sees
a varying intensity of reflected laser light according to the number
and spacing of the 'burned' areas of the disc, and this represents the
binary channel code recorded to the disc.

'Bumps' are indeed the restricted to pressed CDs, and produce the
required varying intensity of reflected light through phase
cancellation of the light reflected from the tops of the bumps and the
surrounding lands.

Apologies for any confusion caused in this detail of that particular
Q&A.

Kindest regards to all our readers,

hugh

[Jay Levitt]

In article >,
says...
> Apologies for any confusion caused in this detail of that particular
> Q&A.

See.. I knew there was a reason I subscribed to SOS.

Thanks, Hugh!

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

[Jay Levitt]

In article >,
says...
> Apologies for any confusion caused in this detail of that particular
> Q&A.

See.. I knew there was a reason I subscribed to SOS.

Thanks, Hugh!

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

[Ty Ford]

On Mon, 15 Nov 2004 15:15:11 -0500, Mike Rivers wrote
(in article <znr1100532431k@trad>):

>
> In article > writes:
>
>> Brain Fart; happens now and then.
>
> Was the path of that fart from the brain to the asshole or the asshole
> to the brain?
>
> Makes a difference whether it's a pit or a bump.

I surmise it was actually difficult to say because of a peculiar circular
breathing technique that was employed. On the other hand, some might consider
the first part of your query redundant! :)

Regards,

Ty Ford




-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

[Ty Ford]

On Mon, 15 Nov 2004 15:15:11 -0500, Mike Rivers wrote
(in article <znr1100532431k@trad>):

>
> In article > writes:
>
>> Brain Fart; happens now and then.
>
> Was the path of that fart from the brain to the asshole or the asshole
> to the brain?
>
> Makes a difference whether it's a pit or a bump.

I surmise it was actually difficult to say because of a peculiar circular
breathing technique that was employed. On the other hand, some might consider
the first part of your query redundant! :)

Regards,

Ty Ford




-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

[xy]

Jay, you serious?


I thought factory vs. home cd's were made basically the same way, but
the factory had faster and more robust machinery.

[xy]

Jay, you serious?


I thought factory vs. home cd's were made basically the same way, but
the factory had faster and more robust machinery.

[Scott Dorsey]

In article >,
xy > wrote:
>Jay, you serious?
>
>
>I thought factory vs. home cd's were made basically the same way, but
>the factory had faster and more robust machinery.

No. CD-Rs are not CDs. Not even a little bit. They are a dye image,
and they do not have anything like the long-term stability of CD pressings.
They also tend to have much higher error rates.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

In article >,
xy > wrote:
>Jay, you serious?
>
>
>I thought factory vs. home cd's were made basically the same way, but
>the factory had faster and more robust machinery.

No. CD-Rs are not CDs. Not even a little bit. They are a dye image,
and they do not have anything like the long-term stability of CD pressings.
They also tend to have much higher error rates.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[David Morgan \(MAMS\)]

"xy" > wrote in message om...
> Jay, you serious?
>
>
> I thought factory vs. home cd's were made basically the same way, but
> the factory had faster and more robust machinery.


I'm feeling a little ignorant here myself, but factory replication is done from
a reverse glass master and is 'stamped' much like vinyl was. It's a rather
massive process involving a lot of robotics and sterile atmosphere.

I've been burning CDs in the studio for almost 17 years and never realized
the process involved tinting the dye rather than burning pits. How much we
take for granted sometimes.... :-(

--
David Morgan (MAMS)
http://www.m-a-m-s DOT com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.artisan-recordingstudio.com

[David Morgan \(MAMS\)]

"xy" > wrote in message om...
> Jay, you serious?
>
>
> I thought factory vs. home cd's were made basically the same way, but
> the factory had faster and more robust machinery.


I'm feeling a little ignorant here myself, but factory replication is done from
a reverse glass master and is 'stamped' much like vinyl was. It's a rather
massive process involving a lot of robotics and sterile atmosphere.

I've been burning CDs in the studio for almost 17 years and never realized
the process involved tinting the dye rather than burning pits. How much we
take for granted sometimes.... :-(

--
David Morgan (MAMS)
http://www.m-a-m-s DOT com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.artisan-recordingstudio.com

[Bob Cain]

David Morgan (MAMS) wrote:
> "xy" > wrote in message om...
>
>>Jay, you serious?
>>
>>
>>I thought factory vs. home cd's were made basically the same way, but
>>the factory had faster and more robust machinery.
>
>
>
> I'm feeling a little ignorant here myself, but factory replication is done from
> a reverse glass master and is 'stamped' much like vinyl was. It's a rather
> massive process involving a lot of robotics and sterile atmosphere.
>
> I've been burning CDs in the studio for almost 17 years and never realized
> the process involved tinting the dye rather than burning pits. How much we
> take for granted sometimes.... :-(

The idea is to keep a reflection from getting to the
detector. Bumps use dispersion and dyes use absorption.

I believe that in either case all that edges are used for is
slaving the phase locked loop to give an indication of
where the middle of the bit is. Slop at the edges is ok
because the middle is bigger than the slop.


Bob
--

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

A. Einstein

[Bob Cain]

David Morgan (MAMS) wrote:
> "xy" > wrote in message om...
>
>>Jay, you serious?
>>
>>
>>I thought factory vs. home cd's were made basically the same way, but
>>the factory had faster and more robust machinery.
>
>
>
> I'm feeling a little ignorant here myself, but factory replication is done from
> a reverse glass master and is 'stamped' much like vinyl was. It's a rather
> massive process involving a lot of robotics and sterile atmosphere.
>
> I've been burning CDs in the studio for almost 17 years and never realized
> the process involved tinting the dye rather than burning pits. How much we
> take for granted sometimes.... :-(

The idea is to keep a reflection from getting to the
detector. Bumps use dispersion and dyes use absorption.

I believe that in either case all that edges are used for is
slaving the phase locked loop to give an indication of
where the middle of the bit is. Slop at the edges is ok
because the middle is bigger than the slop.


Bob
--

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

A. Einstein

[Geoff Wood]

"xy" > wrote in message
om...
> Jay, you serious?
>
>
> I thought factory vs. home cd's were made basically the same way, but
> the factory had faster and more robust machinery.

You were totally wrong !

geoff

[Geoff Wood]

"xy" > wrote in message
om...
> Jay, you serious?
>
>
> I thought factory vs. home cd's were made basically the same way, but
> the factory had faster and more robust machinery.

You were totally wrong !

geoff

[Ty Ford]

On Tue, 16 Nov 2004 17:55:04 -0500, David Morgan \(MAMS\) wrote
(in article <czvmd.10267$pP5.2451@trnddc05>):

>
> "xy" > wrote in message
> om...
>> Jay, you serious?
>>
>>
>> I thought factory vs. home cd's were made basically the same way, but
>> the factory had faster and more robust machinery.
>
>
> I'm feeling a little ignorant here myself, but factory replication is done
> from
> a reverse glass master and is 'stamped' much like vinyl was. It's a rather
> massive process involving a lot of robotics and sterile atmosphere.
>
> I've been burning CDs in the studio for almost 17 years and never realized
> the process involved tinting the dye rather than burning pits. How much we
> take for granted sometimes.... :-(


Right, "regular" CDs are made by a physical stamping process from a reverse
master (not unlike vinyl records).

CD-R are laser burned.

Regards,

Ty Ford




-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

[Ty Ford]

On Tue, 16 Nov 2004 17:55:04 -0500, David Morgan \(MAMS\) wrote
(in article <czvmd.10267$pP5.2451@trnddc05>):

>
> "xy" > wrote in message
> om...
>> Jay, you serious?
>>
>>
>> I thought factory vs. home cd's were made basically the same way, but
>> the factory had faster and more robust machinery.
>
>
> I'm feeling a little ignorant here myself, but factory replication is done
> from
> a reverse glass master and is 'stamped' much like vinyl was. It's a rather
> massive process involving a lot of robotics and sterile atmosphere.
>
> I've been burning CDs in the studio for almost 17 years and never realized
> the process involved tinting the dye rather than burning pits. How much we
> take for granted sometimes.... :-(


Right, "regular" CDs are made by a physical stamping process from a reverse
master (not unlike vinyl records).

CD-R are laser burned.

Regards,

Ty Ford




-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

[TonyP]

"xy" > wrote in message
om...
> I thought factory vs. home cd's were made basically the same way, but
> the factory had faster and more robust machinery.

You thought wrong.

TonyP.

[TonyP]

"xy" > wrote in message
om...
> I thought factory vs. home cd's were made basically the same way, but
> the factory had faster and more robust machinery.

You thought wrong.

TonyP.

[Lorin David Schultz]

"Geoff Wood" -nospam> wrote:
>
> Sound On Sound is generally very concise.



The remarks Jay quoted *were* concise. Unfortunately, they were also
incorrect.

--
"It CAN'T be too loud... some of the red lights aren't even on yet!"
- Lorin David Schultz
in the control room
making even bad news sound good

(Remove spamblock to reply)

[Lorin David Schultz]

"Geoff Wood" -nospam> wrote:
>
> Sound On Sound is generally very concise.



The remarks Jay quoted *were* concise. Unfortunately, they were also
incorrect.

--
"It CAN'T be too loud... some of the red lights aren't even on yet!"
- Lorin David Schultz
in the control room
making even bad news sound good

(Remove spamblock to reply)