"Dave Plowman (News)" wrote in message
...
So logically transferring a pristine LP to CD (without any 'mastering')
gives the best of both worlds - the distortions of the LP without the wear
problems.

Only *some* people actually believe that vinyl distortions are "best"
though.
Others realise the best performance/mastering job are not unique to any
media.

MrT.

In article ,
Mr.T MrT@home wrote:
Only *some* people actually believe that vinyl distortions are "best"
though.

Indeed.

Others realise the best performance/mastering job are not unique
to any media.

There's no doubt of the trend to try and win the 'loudness war' with many
pop CDs, though. Something that has always bemused me.

I was first sort of aware of it many years ago when DAT took over from
cassette on the demo front. Demo cassettes were always peaked to maximum
(and beyond) with *some* justification, I suppose, given the often poor
quality of the replay equipment. But then exactly the same happened with
DAT when to the best of my knowledge no one produced a cheap DAT all in
one playback system to rival a simple cassette player.

--
*Acupuncture is a jab well done*

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

In article , John Phillips
wrote:
On 2006-10-29, Geoff wrote:
Jim Lesurf wrote:

In fairness, I should point out, though, that the first generation
Philips '14 bit' chipsets for CD players actually used x4
oversampling. Thus - in principle at least - returned 16-bit
resolution.

Pray tell how oversampling increases resolution ? The reason for
oversampling was/is to make reconstruction filters easier to implemnt
without artifiacts of a steep slope. It's been a whil, have I
forgotten ?

I have sometimes wondered about the Philips x4 upsampling DAC in early
CD players (I use "upsampling" here to distinguish from the use of
oversampling in the ADC case).

I'd prefer to call it 'oversampling' in both cases for various reasons. One
being that in some situations 'upsampling' may be a distinctly different
practice.

I assume (but have never looked for proof) that the conversion of a
single 16-bit sample xx..xxYY (YY are the two LSBs) would be
accomplished by replacing the single 16-bit sample by four 14-bit
samples as follows:

xx..xx00: xx..xx, xx..xx, xx..xx, xx..xx

xx..xx01: xx..xx, xx..xx, xx..xx, xx..xx+1

xx..xx10: xx..xx, xx..xx, xx..xx+1, xx..xx+1

xx..xx11: xx..xx, xx..xx+1, xx..xx+1, xx..xx+1

Or something similar. The DAC will effectively interpolate so the LSBs
are not lost. The noise floor will be right for 16 bits because of the
upsampling.

I wonder if the amplitudes of the preceding and succeding samples should
be taken into account to determine the right order of the +1s in the
interpolation? Probably not as I suspect the spectrum differences will
fall above the original Nyquist limit.

The above is essentially the same explanation that I would have given,
but since John puts it quite neatly, I need not bother. :-) A more
detailed explanation is given in the special issue of Philips Tech Rev
that was released at the same time as CD audio was launched, and
describes CD audio and the initial chipsets.

The samples are 'noise shaped'[1] by a process along the lines that the top 14
bits of each sample are DAC converted and fed out as an analog level, and
the 'unused' 2 LSB are fed back and combined with the next sample value.
The simplest method is the one described above, but alternative feedback
shaping processes can be used.

The output filter then acts to take a 'running average'. Four 14 bit values
then sum or average to give a 16-bit result in the passband of the analogue
filtering arrangement.

In principle, the behaviour is the same as when any 'low bit depth' DAC is
used (with oversampling and noise shaping) to get results with higher
depths.

Thus by using oversampling and noise shaping we can symultaneously ease the
burden on the analog reconstruction filter that follows DAC conversion, and
allow the use of a DAC with less than 16 bits. This also is the basis of
other methods like low-bit DAC delta-sigma, 'bitstream', and various other
commercial techniques which use the same general approach to obtain both
a shift of reconstruction images to higher frequencies (thus easing analog
filter requirements) and obtaining high resolutions.

Hence the original Philips 14-bit x4 oversampling system would be able,
in principle, to deliver full 16-bit resolution *if* the chips and the
associated electronics was made with suitable care. As usual, the practical
limits end up being determined by the care put into engineering the
actual implimentation. :-)

Slainte,

Jim

[1] I regret the term 'noise shaped' in this context since we are talking
about a deterministic process, but it became the standard term, so we
seem to be stuck with it!

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

wrote in message
oups.com
Arny Krueger wrote:
wrote in message
oups.com
Mr.T wrote:
wrote in message
oups.com...
No. you were the fool who insisted that all LPs were
mastered with summed bass and HF roll off. Are you
back to make some more ridiculous claims?

Pity the cartridge trying to track a record with large
amounts of non summed bass :-)

Have you ever heard it? I have.

Sure, many times on CDs and other digita formats where
it is no great shakes, even on the lowest-cost equipment.

I see you have heard a cartridge trying to track a record
with large amounts of non summed bass many times on CDs
and other digital formats.

Sure, because a CD is a record of a musical performance.

With a real high end rig it is fantastic.

Only to a point, which depends on many things.

How would you know?

About 50 years of experience with the theory and the practice of making and
playing music.

Hardly a pity.

Sure it is a pity when the need for megabux equipment to
play means that almost all vinyl ever cut has summed
bass.

No it doesn't.

Ignorance of the well-known properties of vinyl technology noted.

Get your facts straight. oh jeez did I
just ask the village fool to get his facts straight? my
bad.

Meltdown noted.

"Geoff" wrote in message

Jim Lesurf wrote:
In article
, Mr.T
MrT@home wrote:
16 bits was an obvious choice because it's two bytes
and provides a sufficient degree of overkill. What you
could also say is that not for nothing was the early
use and acceptance of 14 bit CD players, when 16 bit
converters were more difficult/expensive to make.

In fairness, I should point out, though, that the first
generation Philips '14 bit' chipsets for CD players
actually used x4 oversampling. Thus - in principle at
least - returned 16-bit resolution.

Pray tell how oversampling increases resolution ?

http://www.daqchina.net/daqchina/circuit/adpro.pdf

The reason for oversampling was/is to make reconstruction
filters easier to implemnt without artifiacts of a steep
slope.

That's one reason of several.

It's been a whil, have I forgotten ?

yep.

"Rob" wrote in
message


I don't think anyone who prefers vinyl would argue that,
for example, dynamic range and S/N of CD is potential
better (although I prefer different). There is no proof,
BTW, that CD is better than vinyl in absolute terms.

FYI, dynamic range and S/N are analogous.

The CD format has 4 undeniable advantages over the LP format in absolute
terms:

(1) Dynamic range
(2) Vastly reduced nonlinear distortion (actually implied by item 1)
(3) Vastly reduced linear distortion, AKA frequency and phase response in
the audio band
(4) Robustness and general practicality as a distribution medium.

When I say "absolute" I mean that the above advantages are stated using
standard technical terms that are generally understood as common technical
terms related to the audio arts.

They are undeniable facts that are generally true under all reasonable
circumstances.

They can be found in papers in widely-recognized refereed professional audio
technical publications (e.g. IEEE and AES).

They can be determined and compared by standard mechanical (or electrical)
means that are generally-recognized and very low in terms of personal bias.

They are also generally true when evaluated in bias-controlled listening
tests.

Almost all consumers of audio recordings accept that they are true if they
have any amount of personal experience with both mediums.

The only people who disagree with any of them are themselves highly biased.

wrote in message
ups.com

And yet you have never done a bias controled listening
test using SOTA lp playback gear and SOTA vinyl to verify
this claim.

The definition of SOTA lp playback gear and SOTA vinyl is not generally
agreed-upon, and does have a stable definition.

The corresponding equipment is not practical for ordinary mortals who are
unwilling to mortage their children's future, to own.

In contrast I can define an adequte reference SOTA digital music player for
comparison as follows:

A good CD or DVD player, costing $39 and up.

I can also define an adequate media production/reproduction facility for the
digital side:

A ca. $400 Dell PC with CD or DVD burner and onboard audio interface.

"Dave Plowman (News)" wrote in
message
In article
. com,
wrote:
I already pointed out some specific examples of that
travesty. The meter readers seemed utterly ans
completely disinterested when I started talking about
specific examples of terrible sounding CDs that are
trumped by great sounding LPs of the same title.

Oh that isn't a problem for incompetent engineers.
However, to make an LP sound as good as a well recorded
CD is impossible. And that's the crux of the matter.

Even just making an adequate high speed analog tape master for cutting the
LP is mission impossible.

http://www.provide.net/~djcarlst/abx_tapg.htm

"Don Pearce" wrote in message

On Mon, 30 Oct 2006 19:27:47 +1100, "Mr.T" MrT@home
wrote:


wrote in message
ups.com...
And yet you have never done a bias controled listening
test using SOTA lp playback gear and SOTA vinyl to
verify this claim.

I have, and it was a lay down misere for vinyl I'm
afraid. (for those who don't play cards, it's where you
lose every trick :-)


Do you mean a misere ouvert?

But the necessity of using a $100,000 turntable to
compete (and lose) against a $500 CD player was the
really amusing part!


That would be a $50 CD surely?

$39 or less in the USA. ;-)

In article ,
Arny Krueger wrote:

[snip]
Almost all consumers of audio recordings accept that they are true if
they have any amount of personal experience with both mediums.

The only people who disagree with any of them are themselves highly
biased.

Or so lacking in knowledge they blame the CD medium for other reasons. And
enjoy fiddling with pickups, etc.

--
*It is wrong to ever split an infinitive *

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