"Dave Plowman (News)" wrote in message
...
In article .com,
Have you ever had the chance to experiment with a variety of programme
material over a wide range of sampling frequencies, etc? Proper blind
testing? It's quite revealing. The crunch point comes at about 12 bits
(straight) Once you use companding or over sampling the waters get cloudy.
The figures for NICAM TV sound - 11 bit companded - and CD at 16 bit
weren't plucked out of the air as some seem to think.

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.

As for companded systems and compressed data formats, it's always a trade
off for any number of reasons.

MrT.

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.

Slainte,

Jim

--
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

"Jim Lesurf" wrote in message
...
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.

At least that's what they wanted you to believe.

MrT.

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 ? 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 ?

geoff

On 2006-10-29, Geoff wrote:
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 ? 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 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.

John
--
John Phillips

"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.

wrote in message
oups.com...

Geoff wrote:
Richard Crowley wrote:
"Serge Auckland" wrote ...

I have deliberately avoided the argument as to whether even 16bit is
excessive for vinyl.........

Didn't think there was any argument?
Is ANY vinyl capable of SNR in excess of 16 bits?

Try 12 bits.

Try using your ears instead.

Hiss, tic, tic, pop.

But if you can't, at least try to get some meaningful data on the subject.


Letsee, measurements can't be used, and neither can listening unless it
produces the *right* results.

What you have going there is about as
meaningful as a manufacturer's THD measuements are for an amp.

Obviously Scott, you don't remember what audio was like before amp THD specs
got to be reasonable.

On 2006-10-25, Geoff wrote:
Richard Crowley wrote:
"Serge Auckland" wrote ...

I have deliberately avoided the argument as to whether even 16bit is
excessive for vinyl.........

Didn't think there was any argument?
Is ANY vinyl capable of SNR in excess of 16 bits?

Try 12 bits.

Possibly a little optimistic. We have seen earlier on uk.rec.audio
the reference to RCA's research into SOTA vinyl which gave 60 dB as the
A-weighted SNR you could achieve with the *best available* vinyl.

That would be nominally 10 bits. However if you are prepared to let
distortion on peak signals reach up to 10% or so you can get more.

Actually a genuine 60 dB is quite good enough for most performances
reproduced in the home. My own experience is that more than that
(I only have one or two recordings which use more) makes setting the
"right" volume level for the entire performance difficult.

The flies in the vinyl ointment, however, are

1. Typical retail vinyl has not been SOTA. More of it may come close
these days since the absolute volume of sales is so low but in the past
the quality, in my personal experience, was nowhere near SOTA.

2. The single A-weighted SNR figure hides a frequency-dependent noise
floor which rises from about 500 Hz downwards.

--
John Phillips

In article , John Phillips
wrote:
On 2006-10-25, Geoff wrote:
Richard Crowley wrote:

Didn't think there was any argument? Is ANY vinyl capable of SNR in
excess of 16 bits?

Try 12 bits.

Possibly a little optimistic. We have seen earlier on uk.rec.audio the
reference to RCA's research into SOTA vinyl which gave 60 dB as the
A-weighted SNR you could achieve with the *best available* vinyl.

That would be nominally 10 bits. However if you are prepared to let
distortion on peak signals reach up to 10% or so you can get more.

The following may help.

http://www.st-and.demon.co.uk/AudioM...ons/page1.html

and

http://www.st-and.demon.co.uk/AudioM...ons/page2.html

The second page may be particularly relevant here. It is based on industry
measurements on not only LPs, but also on the previous stages in the LP
production process, etc, as reported by manufacturers in JAES. Also on
similar work on the playback systems. Details in the references listed on
the pages.

The pages are a version of an article from 'Hi Fi News'. They don't say
anything 'new', but just explain what is in the professional literature.

Slainte,

Jim

--
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

In rec.audio.tech Jim Lesurf wrote:
In article , John Phillips
wrote:
On 2006-10-25, Geoff wrote:
Richard Crowley wrote:

Didn't think there was any argument? Is ANY vinyl capable of SNR in
excess of 16 bits?

Try 12 bits.

Possibly a little optimistic. We have seen earlier on uk.rec.audio the
reference to RCA's research into SOTA vinyl which gave 60 dB as the
A-weighted SNR you could achieve with the *best available* vinyl.

That would be nominally 10 bits. However if you are prepared to let
distortion on peak signals reach up to 10% or so you can get more.

The following may help.

http://www.st-and.demon.co.uk/AudioM...ons/page1.html

and

http://www.st-and.demon.co.uk/AudioM...ons/page2.html

The second page may be particularly relevant here. It is based on industry
measurements on not only LPs, but also on the previous stages in the LP
production process, etc, as reported by manufacturers in JAES. Also on
similar work on the playback systems. Details in the references listed on
the pages.

The pages are a version of an article from 'Hi Fi News'. They don't say
anything 'new', but just explain what is in the professional literature.


See also the 'extra page' where Mr. Lesurf responds to reader comments.

http://www.st-and.demon.co.uk/AudioM...s/letters.html



___
-S
"As human beings, we understand the world through simile, analogy,
metaphor, narrative and, sometimes, claymation." - B. Mason