Jim Lesurf wrote:

all you need to do is stream the data to a DAC, and as long as you have
a buffer (cheap) that can ensure the bits arrive without timing
irregularities (also cheap), you have something that's limited only by
the quality of the DAC.

You missed out a few points.

Firstly, that means you need a DAC. If someone chooses a CD Player that
comes in the box already, so saves the user from needing another box, with
yet more PSU, metalwork, etc.

I was asking about it from the point of view of the manufacturers, or at
least, as a viable technical solution, rather than from the point of
view of the consumer. Sorry, that wasn't very clear.

Clearly, the discerning hi-fi consumer will buy whatever seems to work
for them at the right price.

But, why do the manufacturers design and build CD players the way they
do?

From the point of view of creating a device from available componentry,
and then perhaps putting it on the market to compete against other
high-quality CD-playing devices, it's:

* very cheap to get all the data off a CD into RAM or another buffer
* very cheap to feed that data into a DAC with exquisite timing

The cheapest CDROM drive has to scrape every bit off a disc in order to
function as a reliable device for digital storage of software and data.
Presumably it can do just the same job for a music CD.

It might be cool to design a CD player with a solid, weighty chassis and
aerospace-grade bearings - but if the job of getting data off it can be
done as effectively by a transport + reader + data interface that costs
peanuts, why spend money doing that when it could be spent where it
would make more difference (a better DAC, a better control interface, a
better PSU)?

It's still not clear to me whether I'm missing something about how CD
audio actually works, or whether the CD player as we've known it for the
last 30+ years is an anachronism.

Daniele

In article
,
D.M. Procida wrote:
The cheapest CDROM drive has to scrape every bit off a disc in order to
function as a reliable device for digital storage of software and data.
Presumably it can do just the same job for a music CD.

You wouldn't want the average CDROM drive in a CD player. Too noisy.

--
*Strip mining prevents forest fires.

Dave Plowman London SW
To e-mail, change noise into sound.

In article
,
D.M. Procida wrote:
Jim Lesurf wrote:

all you need to do is stream the data to a DAC, and as long as you
have a buffer (cheap) that can ensure the bits arrive without timing
irregularities (also cheap), you have something that's limited only
by the quality of the DAC.

You missed out a few points.

Firstly, that means you need a DAC. If someone chooses a CD Player
that comes in the box already, so saves the user from needing another
box, with yet more PSU, metalwork, etc.

I was asking about it from the point of view of the manufacturers, or at
least, as a viable technical solution, rather than from the point of
view of the consumer. Sorry, that wasn't very clear.

Clearly, the discerning hi-fi consumer will buy whatever seems to work
for them at the right price.

But, why do the manufacturers design and build CD players the way they
do?

I'd say it was because each will have their own ideas about the 'best' way
to get good results *and* to make a saelable product. Different engineers
will take different approaches just as different users will have different
priorities and preferences - cf Bob's comments about being able to compare
with a genuine original sound. What suits him may not suit someone else.
Doesn't make either view totally invalid, just personal.


From the point of view of creating a device from available componentry,
and then perhaps putting it on the market to compete against other
high-quality CD-playing devices, it's:

* very cheap to get all the data off a CD into RAM or another buffer *

Is it? On *every* occasion? I fear people may have become so used to Audio
CD, optical drives, etc, that they've forgotten how remarkable it is that
it works at all! :-)

When I first explained to another technician I knew many years ago how CD
Players worked to read the data optically he promptly told me it was
*impossible*. Because the raw data channel resolution seemed to be too high
for the available optical spot size/wavelength. Yet it works. :-)


It's still not clear to me whether I'm missing something about how CD
audio actually works, or whether the CD player as we've known it for the
last 30+ years is an anachronism.

Have you read the orginal Philips papers? They are pretty good. Sorry if
you know all this already, but if not, the Scots Guide does cover some of
the sheer mechanical/optical precision involved. It was made to work on a
mass market level by throwing a lot of money and engineering at the
problems. Now, it seems, taken for granted. Which in one way is telling us
just how successful those engineers were! :-)

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

D.M. Procida wrote:

Clearly, the discerning hi-fi consumer will buy whatever seems to work
for them at the right price.

But, why do the manufacturers design and build CD players the way they
do?

[...]

The cheapest CDROM drive has to scrape every bit off a disc in order to
function as a reliable device for digital storage of software and data.
Presumably it can do just the same job for a music CD.

It might be cool to design a CD player with a solid, weighty chassis and
aerospace-grade bearings - but if the job of getting data off it can be
done as effectively by a transport + reader + data interface that costs
peanuts, why spend money doing that when it could be spent where it
would make more difference (a better DAC, a better control interface, a
better PSU)?

It's still not clear to me whether I'm missing something about how CD
audio actually works, or whether the CD player as we've known it for the
last 30+ years is an anachronism.

In a hotel lobby today, I was leafing through an hi-fi magazine I
happened to see. It reviewed a CD player, opening with a sentence to the
effect that "the CD player as we know it may soon be dead".

This CD player (a Meridian, and rather expensive) apparently uses a
cheap CD-ROM drive to get the data off the disk, and can use the drive's
extra speed to read ahead and buffer it (allowing it for example to have
multiple goes at reading problematic areas of the disk) in pretty much
the way I suggested would be possible.

I assume it's this one:
https://www.meridian-audio.com/en/products/cd-players/reference-808v6/.

So maybe I'm not missing anything... although I do note that this
solution to the problem of playing CDs doesn't actually make the
business cheaper.

Daniele

On 13/11/2017 12:39 AM, D.M. Procida wrote:
Now that the contents of a CD can be held in RAM, never mind in other
cheaper and still very fast digital storage, what does an expensive CD
player offer that a cheap transport and a decent digital-to-analog
converter cannot?

If DAC products can buffer seconds' or even minutes' worth of data, and
can stream it out to the actual DAC circuitry with GHz precision, there
doesn't seem to be much need any more for costly CD players.

Am I missing something?

**A CD player, unlike a computer transport, interpolates errors. It does
not re-request information be re-read. An argument can be made that a
higher quality transport (more expensive) may read disks without issuing
as many errors. Are those errors audible? Unlikely, except under extreme
circumstances. Nonetheless, high quality transports add very
significantly to the cost of a CD player.

More expensive CD players tend to use the (now old fashioned) multi-bit
DACs (parallel), rather than the more common (and FAR less expensive)
single bit DACs (serial). Parallel DACs are MUCH more expensive to
implement, due to the large number of precision resistors and capacitors
required (one for each bit).

Some expensive players use multiple DACs, whose outputs are summed,
allegedly in order to reduce errors.

Some expensive players use very high performance OP amps. Some use
discrete component output stages (my own Harman Kardon HD-970 does),
which inevitably cost more than integrated OP amps.

Some expensive players use valves in the output stages, for some
unknowable reason. This requires a bunch of expensive support circuitry.


Best sounding player I've had in my system?

A Marantz CD80 (ca. 190-ish). Fabulous sounding player. Not stupidly
expensive. Not cheap either.


--
Trevor Wilson
www.rageaudio.com.au

"Trevor Wilson" wrote in message
...
On 13/11/2017 12:39 AM, D.M. Procida wrote:
Now that the contents of a CD can be held in RAM, never mind in
other
cheaper and still very fast digital storage, what does an expensive
CD
player offer that a cheap transport and a decent digital-to-analog
converter cannot?

If DAC products can buffer seconds' or even minutes' worth of data,
and
can stream it out to the actual DAC circuitry with GHz precision,
there
doesn't seem to be much need any more for costly CD players.

Am I missing something?

**A CD player, unlike a computer transport, interpolates errors. It
does not re-request information be re-read. An argument can be made
that a higher quality transport (more expensive) may read disks
without issuing as many errors. Are those errors audible? Unlikely,
except under extreme circumstances. Nonetheless, high quality
transports add very significantly to the cost of a CD player.

More expensive CD players tend to use the (now old fashioned)
multi-bit DACs (parallel), rather than the more common (and FAR less
expensive) single bit DACs (serial). Parallel DACs are MUCH more
expensive to implement, due to the large number of precision
resistors and capacitors required (one for each bit).

Some expensive players use multiple DACs, whose outputs are summed,
allegedly in order to reduce errors.

Some expensive players use very high performance OP amps. Some use
discrete component output stages (my own Harman Kardon HD-970 does),
which inevitably cost more than integrated OP amps.

Some expensive players use valves in the output stages, for some
unknowable reason. This requires a bunch of expensive support
circuitry.


Best sounding player I've had in my system?

A Marantz CD80 (ca. 190-ish). Fabulous sounding player. Not stupidly
expensive. Not cheap either.




Interesting observation.

For some reason I always thought my first 14-bit Philips (CD104?)
sounded better than anything I had later, and that the one that I
bought to replace it some years later (16-bit parallel) also sounded
better. That machine now sits with a very elderly lady we know and I
will reclaim it when she passes. Comparison with my present Marantz
CD5400SE will be interesting.


--
Woody

harrogate3 at ntlworld dot com

I have a cd100 bought in 1983. It sounds pretty good on modern cds, but is
horribly slow to find any tracks and skips if a fly lands on the case.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Woody" wrote in message
news

"Trevor Wilson" wrote in message
...
On 13/11/2017 12:39 AM, D.M. Procida wrote:
Now that the contents of a CD can be held in RAM, never mind in other
cheaper and still very fast digital storage, what does an expensive CD
player offer that a cheap transport and a decent digital-to-analog
converter cannot?

If DAC products can buffer seconds' or even minutes' worth of data, and
can stream it out to the actual DAC circuitry with GHz precision, there
doesn't seem to be much need any more for costly CD players.

Am I missing something?

**A CD player, unlike a computer transport, interpolates errors. It does
not re-request information be re-read. An argument can be made that a
higher quality transport (more expensive) may read disks without issuing
as many errors. Are those errors audible? Unlikely, except under extreme
circumstances. Nonetheless, high quality transports add very
significantly to the cost of a CD player.

More expensive CD players tend to use the (now old fashioned) multi-bit
DACs (parallel), rather than the more common (and FAR less expensive)
single bit DACs (serial). Parallel DACs are MUCH more expensive to
implement, due to the large number of precision resistors and capacitors
required (one for each bit).

Some expensive players use multiple DACs, whose outputs are summed,
allegedly in order to reduce errors.

Some expensive players use very high performance OP amps. Some use
discrete component output stages (my own Harman Kardon HD-970 does),
which inevitably cost more than integrated OP amps.

Some expensive players use valves in the output stages, for some
unknowable reason. This requires a bunch of expensive support circuitry.


Best sounding player I've had in my system?

A Marantz CD80 (ca. 190-ish). Fabulous sounding player. Not stupidly
expensive. Not cheap either.




Interesting observation.

For some reason I always thought my first 14-bit Philips (CD104?) sounded
better than anything I had later, and that the one that I bought to
replace it some years later (16-bit parallel) also sounded better. That
machine now sits with a very elderly lady we know and I will reclaim it
when she passes. Comparison with my present Marantz CD5400SE will be
interesting.


--
Woody

harrogate3 at ntlworld dot com

In article , Woody
wrote:


Interesting observation.

For some reason I always thought my first 14-bit Philips (CD104?)
sounded better than anything I had later, and that the one that I
bought to replace it some years later (16-bit parallel) also sounded
better. That machine now sits with a very elderly lady we know and I
will reclaim it when she passes. Comparison with my present Marantz
CD5400SE will be interesting.

The first player I had was the first gen Marantz using the 14-bit x4
Philips chipset. Happy with it for about a decade. Although I did add some
'Toko' analogue low pass filters that rolled off at about 19 kHz as that
seemed to make the results sound nicer to my ears. Possibly because it cut
down the signal levels slightly going into the amp.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Trevor Wilson
wrote:

**A CD player, unlike a computer transport, interpolates errors. It does
not re-request information be re-read.

You assumes a 'standard' example, so I'll do the same:

It will also read at x1 speed. This can help reduce the chance of
individual read errors, so meaning less need for the strategies used by
'computer' drives which may re-read to combat such errors.


An argument can be made that a higher quality transport (more expensive)
may read disks without issuing as many errors. Are those errors audible?
Unlikely, except under extreme circumstances.

However if someone has hundreds of CDs some may be 'extreme' cases. I
certainly have some that won't play well in some machines, but work better
in others. So if someone only has one player it may be useful to buy a good
one.

I note, though, that "expensive" isn't a synonym for "good" in this regard.
:-)



Some expensive players use multiple DACs, whose outputs are summed,
allegedly in order to reduce errors.

Can also be used to help reduce the effects of intersample peaks requring
an output above 0dBFS. Given how many popular discs have this problem, that
may be useful.


Best sounding player I've had in my system?

A Marantz CD80 (ca. 190-ish). Fabulous sounding player. Not stupidly
expensive. Not cheap either.

The machines which I've found most likely to play a CD without problems are
actually the old Pioneer CDR-509 recorders. These have 'legato link' DACs
which dodge the above oversample problems. But since I'm happy to use an
external DAC I've preferred them feeding either an old Meridian 500 series
DAC or, more recently, a nice Benchmark DAC. (Mainly bought for USB use.)

The above said, I've found some discs that the Pioneers refuse to play
which some other Player then plays OK. So my general impression is that
seems a matter of which area a given player copes with best/worst.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 13/11/2017 02:22, Trevor Wilson wrote:
On 13/11/2017 12:39 AM, D.M. Procida wrote:
Now that the contents of a CD can be held in RAM, never mind in other
cheaper and still very fast digital storage, what does an expensive CD
player offer that a cheap transport and a decent digital-to-analog
converter cannot?

If DAC products can buffer seconds' or even minutes' worth of data, and
can stream it out to the actual DAC circuitry with GHz precision, there
doesn't seem to be much need any more for costly CD players.

Am I missing something?

**A CD player, unlike a computer transport, interpolates errors. It does
not re-request information be re-read. An argument can be made that a
higher quality transport (more expensive) may read disks without issuing
as many errors. Are those errors audible? Unlikely, except under extreme
circumstances. Nonetheless, high quality transports add very
significantly to the cost of a CD player.

Yes, Trevor, you are missing something.

A CD player does not normally interpolate errors. Most don't even try.
What they do is use the multi-level error correction data that comes
with the data to work out what they should have played.

Andy