In article , Jim Lesurf
writes:

In article , Bob Latham
wrote:
The idea of needing a live reference is utter Bunkum, you don't. I've
been to many classical concerts and a few rock ones but it doesn't help
in the slightest.

You do push that boat rather too far. :-)

If you have no clue what a violin or any other instrument sounds like, how
would you decide if what you hear from a CD is 'fidelity'? Ditto for the
sound of a broadcast from a given hall?

I doubt very much that the Chinese violin sitting in one of my
cupboards upstairs sounds exactly like a Strad or Amati. So while
hearing a violin live will help in general terms, even with absolute
auditory recollection, unless you're listening to exactly the same
instrument, the tone will vary to a greater or lesser extent.

--
Mike Fleming

D.M. Procida wrote:

-------------------


And it is remarkable, but also galling, that my
£20 USB optical drive can reliably read anything I put in it, while the
hi-fi CD players in the house that I spent considerably more on will
reliably refuse to play certain discs (and not all the same ones in each
case).


** CD players are unsurprisingly designed to play audio CDs made to the original 1982 Red Book standard. Such disks carry the rectangular logo: "Compact Disc digital audio".

OTOH optical drives are built to a later and very different standard that allows different laser wavelengths, higher speeds, finer track pitches and smaller pit sizes.

It should be no surprise the latter will play non standard audio CDs.

Such CDs should not carry the rectangular logo but rather have a warning to be played only in machines equipped with modern optical drives.



..... Phil

Trevor Wilson wrote:

------------------------
Vir Campestris wrote:



**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.

**No, I'm not missing anything.


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.

**Yes, they do and if error correction schemes fail, they resort to
interpolation. Computer drives do not use interpolation.



** TW is correct, any CD player built to the Red Book standard *interpolates* large errors on the disc. Missing data up to about 3mm of track length ( or 3mS in time ) is corrected by using redundant data on the disc while longer errors get interpolated which is imperfect and sometimes audible.

IME, large errors are caused by serious damage to the disc surface and often cause the laser to loose lock and either skip or start repeating the same sound rapidly.


...... Phil

On 15/11/2017 11:27 AM, Phil Allison wrote:
Trevor Wilson wrote:

------------------------
Vir Campestris wrote:



**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.

**No, I'm not missing anything.


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.

**Yes, they do and if error correction schemes fail, they resort to
interpolation. Computer drives do not use interpolation.



** TW is correct, any CD player built to the Red Book standard *interpolates* large errors on the disc. Missing data up to about 3mm of track length ( or 3mS in time ) is corrected by using redundant data on the disc while longer errors get interpolated which is imperfect and sometimes audible.

IME, large errors are caused by serious damage to the disc surface and often cause the laser to loose lock and either skip or start repeating the same sound rapidly.


**Yep. And this is what I use to test for the capability of the systems
to correct large errors:

https://www.stereophile.com/content/...gital-test-cdi

The test disk has calibrated drop-outs from 0.05mm ~ 4mm! The Red Book
standard limit is 0.2mm. I've found a number of (cheap) players can
easily exceed the limit. No player has made it to the 4mm drop-out.


--
Trevor Wilson
www.rageaudio.com.au

In article , Mike Fleming
wrote:
If you have no clue what a violin or any other instrument sounds like,
how would you decide if what you hear from a CD is 'fidelity'? Ditto
for the sound of a broadcast from a given hall?

I doubt very much that the Chinese violin sitting in one of my cupboards
upstairs sounds exactly like a Strad or Amati. So while hearing a violin
live will help in general terms, even with absolute auditory
recollection, unless you're listening to exactly the same instrument,
the tone will vary to a greater or lesser extent.

Yes, and changing the tuning of a piano or the strings of a violin alters
the sound. Just as changing venue will, or even playing further from the
bridge with more force.

But if you sit at home and can't tell the difference between a concert from
the RAH and one from the RFH and convincingly recognise the same sound as
being there, you aren't getting anything like 'fidelity'.

People keep arguing as if an inability to get perfection means that nothing
can be done. I know the Civil Service love this ploy, and debaters use it.
But the reality is that if you want to hear a sound as similar as possible
to what you'd get in a live venue, then you do need to have some idea what
that actually sounds like. :-)

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

Phil Allison wrote:

D.M. Procida wrote:

-------------------


And it is remarkable, but also galling, that my
£20 USB optical drive can reliably read anything I put in it, while the
hi-fi CD players in the house that I spent considerably more on will
reliably refuse to play certain discs (and not all the same ones in each
case).


** CD players are unsurprisingly designed to play audio CDs made to the
original 1982 Red Book standard. Such disks carry the rectangular logo:
"Compact Disc digital audio".

OTOH optical drives are built to a later and very different standard that
allows different laser wavelengths, higher speeds, finer track pitches and
smaller pit sizes.

It should be no surprise the latter will play non standard audio CDs.

Such CDs should not carry the rectangular logo but rather have a warning
to be played only in machines equipped with modern optical drives.

I'm talking about standard audio CDs.

Daniele

On 15/11/2017 09:20, Jim Lesurf wrote:
In article , Mike Fleming
wrote:
If you have no clue what a violin or any other instrument sounds like,
how would you decide if what you hear from a CD is 'fidelity'? Ditto
for the sound of a broadcast from a given hall?

I doubt very much that the Chinese violin sitting in one of my cupboards
upstairs sounds exactly like a Strad or Amati. So while hearing a violin
live will help in general terms, even with absolute auditory
recollection, unless you're listening to exactly the same instrument,
the tone will vary to a greater or lesser extent.

Yes, and changing the tuning of a piano or the strings of a violin alters
the sound. Just as changing venue will, or even playing further from the
bridge with more force.

But if you sit at home and can't tell the difference between a concert from
the RAH and one from the RFH and convincingly recognise the same sound as
being there, you aren't getting anything like 'fidelity'.


I'd pretty much agree that you should be able to appreciate a difference.

People keep arguing as if an inability to get perfection means that nothing
can be done. I know the Civil Service love this ploy, and debaters use it.
But the reality is that if you want to hear a sound as similar as possible
to what you'd get in a live venue, then you do need to have some idea what
that actually sounds like. :-)


I think you're deploying shifting sands here. I don't think anybody is
asking for perfection. Just a rendition of audio that gives a decent
approximation of what might be expected.

That expectation can be derived from a live performance, or sleeve
notes, or simply what you might imagine.


--
Cheers, Rob

On 14/11/2017 13:45, Dave Plowman (News) wrote:
In article ,
RJH wrote:
At least with a good quality CD it does sound a bit like the real
thing - but how many people go to live concerts (I'm thinking
classical in any form, jazz, big band or MoR here) these days to know
what real instruments actually sound like?


'A bit'? In my experience of mainly rock/pop, nothing like a live
performance. Even if a domestic hifi could achieve the volume levels,
it'd take a heck of system (and room) to reproduce the bass etc and
'venue' acoustics of live music.

You'd hardly ever set out to record a live gig as heard from the audience.
The trend is to make it as close to a studio session as possible.


Yes of course - partly my point in fact. You wouldn't want a version of
the live performance as experienced.

--
Cheers, Rob

D.M. Procida wrote:

-------------------



And it is remarkable, but also galling, that my
£20 USB optical drive can reliably read anything I put in it, while the
hi-fi CD players in the house that I spent considerably more on will
reliably refuse to play certain discs (and not all the same ones in each
case).


** CD players are unsurprisingly designed to play audio CDs made to the
original 1982 Red Book standard. Such disks carry the rectangular logo:
"Compact Disc digital audio".

OTOH optical drives are built to a later and very different standard that
allows different laser wavelengths, higher speeds, finer track pitches and
smaller pit sizes.

It should be no surprise the latter will play non standard audio CDs.

Such CDs should not carry the rectangular logo but rather have a warning
to be played only in machines equipped with modern optical drives.

I'm talking about standard audio CDs.

Daniele


** No you are not, cos like anyone you have no idea if a given CD is "standard" or not.

If you bothered to read my post, you would see that it refers to CDs being sold that do not comply despite having the rectangular logo.

The commonest example is CDs that exceed 74mins.



..... Phil

Phil Allison wrote:

** CD players are unsurprisingly designed to play audio CDs made to the
original 1982 Red Book standard. Such disks carry the rectangular logo:
"Compact Disc digital audio".

I'm talking about standard audio CDs.

** No you are not, cos like anyone you have no idea if a given CD is
"standard" or not.

If you bothered to read my post, you would see that it refers to CDs being
sold that do not comply despite having the rectangular logo.

Perhaps you ought to read what you write more carefully in that case.
And perhaps be a little less rude while you're at.

Daniele