In article , Bob Latham
wrote:
In article , Dave Plowman (News)
wrote:

Surly you've heard the results of a digital stream being 'lost'? On
DAB or FreeView? It doesn't effect any of the analogue parameters
'depth' 'space' 'positioning' etc. It's usually a bloody great hole
followed by a chirps and bangs as things attempt to sync up again...

You'll effect these things by reducing the data rate. But no cable
can do do this.

I'm almost in full agreement with this but due to lack of knowledge
there are still a couple of "maybes" in my head.

A cable carrying a digital data stream presumably square waves, will
distort the shape of that wave. Hope we have no argument so far.

Bear in mind that "square waves" are a convenient mathematical fiction. In
reality the signal can't have discontinuities which change the level in
zero time as this would require an (impossible) infinite bandwidth.

Thus a real receiver can't, and does not work on a basis that requires this
- otherwise it would never work. :-) Good engineers may be lazy, but they
aren't daft. ;-

In principle, you can invoke all kinds of 'effects' that, due to the
imperfections of real systems and cables, 'might' affect the results. A
common example, beloved of magazine reviewers in this context being
'jitter'. Yet in practice, when people measure this they tend to find that,
below a fairly high level, no-one has shown they can hear any resulting
changes when tested solely on the basis of the sounds...

Hence this seems to be yet another example of an area in audio where some
reviewers and sellers blow up something out of context in order to give
them a 'scientifically plausible reason' for the differences they say they
can hear - yet often have not demonstrated are audible to them solely on
the basis of the resulting sounds.

You will in a similar way find many 'reviews' which quote values and use
them to try and support comments by the reviewer. Unfortunately, some
knowledge on the part of the reader may be required to distinguish 'fact
from fantasy' in such reviews on occasion...

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

Well I'm sorry you think I'm lazy Dave, but make no apology for top posting.
It's the generally accepted norm now in most groups I subscribe to (like
you, over 20), and makes absolute sense when using a newsreader (no, not
just Outlook Express):

- The context is not required, because the thread structure can be followed
perfectly easily using the message list. It's good manners to leave it in
the message, in case your reply is downloaded from a server that hasn't kept
the old messages, but expecting that everyone wants to read the whole thread
in every reply, especially if they have to scroll past it all to get to the
new bit, is just silly.

- Top posting doesn't remove the context; it's still there if you need it,
but it does allow people to see the reply they're likely to be looking for
first. In fact top posting allows you to leave the ENTIRE context in place,
whereas most bottom posters delete everything except the message they're
replying to. What if someone needs to see the message three up to make sense
of your reply? Bottom posters remove far more information than top posters
do.

- If you search on Google groups or just about any other web interface,
you'll see the first few lines of a message in the results summary. Bottom
posting destroys the usefulness of that completely.

- If you have a slow connection (less and less do now on desktops, but more
and more do on mobile devices), one standard way to save bandwidth is to
limit each message to X kb, which truncates the message after a few lines.
Bottom posting forces everyone to download the whole message.

- Bottom posting and interleaving, or inline replies, are not the same
thing. Interleaving is used where you want to give separate replies to
several points, and is the only logical way to do it, in personal e-mails,
newsposts, web forums and e-mail lists.

Just like £120 cables vs. bell wire, classical vs. pop, vinyl vs. CD, active
vs. passive, MS vs. Apple and Pocket PC vs. Palm, there are two schools of
thought, and neither is likely to convince the other. Therefore I'll live
with your waste of space/bandwidth and inconsiderate demands that I scroll
far more than necessary, if you'll refrain from calling people you don't
know lazy.

Mark

"Dave Plowman (News)" wrote in message
...
In article ,
Mark R Penn wrote:
No it isn't. I can see that in this group, the majority bottom post, but
in most others it's considered old fashioned and bad manners nowadays.

Strange. I read some 20 newsgroups and subscribe to half a dozen e-mail
lists. And it's only the lazy who can't be bothered to trim that top post
because that's how OE is set up to 'work'. And this applies to both the UK
and US.

Private e-mails are a totally different matter - you'd be expected to
remember the discussion. So previous mail(s) are only quoted for
reference.

Newsgroups are a different matter completely. Many posts will be replied
to commenting on various points. So it makes sense to interleave and put
your comment below the OP one so it makes some sense. If you accept this
then top posting where this isn't needed makes no sense whatsoever.

--
*A day without sunshine is like... night.

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

In article , Bob Latham wrote:
You'll effect these things by reducing the data rate. But no cable can
do do this.

I'm almost in full agreement with this but due to lack of knowledge there
are still a couple of "maybes" in my head.

A cable carrying a digital data stream presumably square waves, will
distort the shape of that wave. Hope we have no argument so far.

Not actually square waves because that would require infinite bandwidth, but
a defined waveshape, which if necessary can be recreated by resampling. Yes,
the waveshape can become distorted, but provided resampling is done before
distortion is bad enough to cause errors, the error rate due to distortion in
the transmission path itself can be kept to zero.

If I knew that the receiver was correctly managing to resolve the ones and
zeros and that their edge shape was having no effect on the DAC because
there was a 1 kilo byte or so FIFO buffer before the DAC and that no
additional "guessing" due to distorted data was going on then that would
be great.

That's the whole point of digital transmission. Details vary, but the general
principle with one-way transmission is that slightly more information is sent
than would be necessary to encode the signal if transmission were perfect.
The extra information is encoded in such a way that random errors below a
certain error rate can be completely corrected, i.e. there is suffcient
information to recreate the exact original bitstream.

Also, individual bytes of the information are redistributed in such a way
that a data dropout (a burst of interference on a radio transmission, or a
blemish on a disc or tape surface) will be very unlikely to obliterate
samples that were adjacent in the original bitstream. Therefore, even at an
eror rate higher than that at which perfect error correction can be done, it
is still possible to make a guess at the missing samples by interpolation
because the ones immediately on either side of them will be intact. We might
call this "error concealment", rather than "error correction". While it
wouldn't be possible with a computer file where every byte must be perfect,
it works very well where the bytes represent samples of partially predictable
material such as audio or video.

To summarise, if proper care is taken with transmission/recording of digital
audio and video signals, errors can be kept to zero even allowing for some
random dropouts due to interference or recording surface blemishes, and even
some dropouts in excess of what can be corected can be convincingly
concealed.

Couple that with knowing that there was no effect being caused by the
quality (or lack of) of ground connection between the two devices and I
would then be happy to say the above is 100%. The cable is having no
effect and anything heard is imagination.

There's the Q-word again. What physical property are you talking about when
you refer to the "quality" of a ground connection? If it's something real, it
can be measured and kept within defined limits. Engineering isn't magic.

I don't have that knowledge.

I hope I have managed to supply some that is helpful.

Rod.

On Sat, 26 Nov 2005 15:57:13 GMT, Roderick Stewart
wrote:

In article , Bob Latham wrote:
You'll effect these things by reducing the data rate. But no cable can
do do this.

I'm almost in full agreement with this but due to lack of knowledge there
are still a couple of "maybes" in my head.

A cable carrying a digital data stream presumably square waves, will
distort the shape of that wave. Hope we have no argument so far.

Not actually square waves because that would require infinite bandwidth, but
a defined waveshape, which if necessary can be recreated by resampling. Yes,
the waveshape can become distorted, but provided resampling is done before
distortion is bad enough to cause errors, the error rate due to distortion in
the transmission path itself can be kept to zero.

If I knew that the receiver was correctly managing to resolve the ones and
zeros and that their edge shape was having no effect on the DAC because
there was a 1 kilo byte or so FIFO buffer before the DAC and that no
additional "guessing" due to distorted data was going on then that would
be great.

That's the whole point of digital transmission. Details vary, but the general
principle with one-way transmission is that slightly more information is sent
than would be necessary to encode the signal if transmission were perfect.
The extra information is encoded in such a way that random errors below a
certain error rate can be completely corrected, i.e. there is suffcient
information to recreate the exact original bitstream.

Also, individual bytes of the information are redistributed in such a way
that a data dropout (a burst of interference on a radio transmission, or a
blemish on a disc or tape surface) will be very unlikely to obliterate
samples that were adjacent in the original bitstream. Therefore, even at an
eror rate higher than that at which perfect error correction can be done, it
is still possible to make a guess at the missing samples by interpolation
because the ones immediately on either side of them will be intact. We might
call this "error concealment", rather than "error correction". While it
wouldn't be possible with a computer file where every byte must be perfect,
it works very well where the bytes represent samples of partially predictable
material such as audio or video.

To summarise, if proper care is taken with transmission/recording of digital
audio and video signals, errors can be kept to zero even allowing for some
random dropouts due to interference or recording surface blemishes, and even
some dropouts in excess of what can be corected can be convincingly
concealed.

Couple that with knowing that there was no effect being caused by the
quality (or lack of) of ground connection between the two devices and I
would then be happy to say the above is 100%. The cable is having no
effect and anything heard is imagination.

There's the Q-word again. What physical property are you talking about when
you refer to the "quality" of a ground connection? If it's something real, it
can be measured and kept within defined limits. Engineering isn't magic.

I don't have that knowledge.

I hope I have managed to supply some that is helpful.

Rod.

Please also bear this in mind. Data is routinely sent over microwave
links, which are vastly dirtier than cables. They are configured so
that the signal to noise ratio is just barely enough - in order to
minimize interference to other links. Despite this, the background
error rate of these links is one bit in ten to the fourteen.

Cables do NOT cause data errors in audio.

d

Pearce Consulting
http://www.pearce.uk.com

"Dave Plowman (News)" wrote in message
...
In article ,
Mark R Penn wrote:
No it isn't. I can see that in this group, the majority bottom post, but
in most others it's considered old fashioned and bad manners nowadays.

Strange. I read some 20 newsgroups and subscribe to half a dozen e-mail
lists.



Streuth!!


(But I agree about top posting - it stinks...)

Mark R Penn wrote:

Incidentally, top posting is a crime...................

No it isn't. I can see that in this group, the majority bottom post,
but in most others it's considered old fashioned and bad manners
nowadays.

In *most others*?? Did you check them all?


To bottom post forces the users of most newsreaders to
scroll all the way down to the bottom of a message to see the reply, ...

Only when the respondent is too dumb to operate their delete key.


--
Wally
www.artbywally.com
www.wally.myby.co.uk

"Jim Lesurf" wrote



I'd prefer people to keep their money and make their own well-informed
decisions on how to spend it, not to hope that some crooks occasionally
give something to a good cause after it has been taken from them on the
basis of falsehoods...


OK, here's where we differ - I don't much care how people spend their money
(within reason - Buddhist 'causing no offence or harm to others' etc.) and
can/could think of a thousand things worse than loopy audio 'tweaks'...

My point, continuing as Devil's Advocate here, is that there is probably
just as much voodoo working when the 'snake oil squealers' decry various
products/practices - whether their objections are based on a solid,
demonstrable, scientific understanding, wishful thinking or just plain
common sense. The fact remains that some people *believe* they perceive
differences and improvements and, as I stated in one of the bits you
snipped, I ain't about to spoil their fun.

(Same goes for people who choose to pay megabucks for loopy expensive 'high
end' kit....)

I have not long come from the WAD forum where someone has posted an
enthusiastic 'converted sceptic post' about bits of Mpingo wood?? - He
seems happy enough! (I don't 'know' the person - I don't know if he's an
idiot or not...?? :-)

Keith G wrote:

My point, continuing as Devil's Advocate here, is that there is
probably just as much voodoo working when the 'snake oil squealers'
decry various products/practices - whether their objections are based
on a solid, demonstrable, scientific understanding, wishful thinking
or just plain common sense. The fact remains that some people
*believe* they perceive differences and improvements and, as I stated
in one of the bits you snipped, I ain't about to spoil their fun.

The point is that the sellers aren't offering belief, they're offering what
is touted as a real physical change. They aren't saying, "Pay far too much
money for this perfectly ordinary bit of copper wire and thereby kid
yourself that it's better because you paid more!", they're saying that their
cables actually *do* sound better. They're nothing but lying, scamming con
artists.


--
Wally
www.artbywally.com
www.wally.myby.co.uk

In *most others*?? Did you check them all?

My apologies - should have said most others I subscribe to, mostly MS PC
based ones.

Only when the respondent is too dumb to operate their delete key.

Which removes the context for others. If you top post you can do what I'm
doing here, copy and paste things you want to respond to specifically, yet
still leave the full context below for everyone else. That avoids the issue
where someone replies to a thread after the messages have been removed from
the servers, and all you see is a single message with "" in the subject.
I see many many messages that just say something like:

" Pocket Informant won't uninstall

So and so wrote:

So can I just change that registry key?

Yes, I think you can do that, though it's not supported officially"

Which makes no sense at all without the FULL context which snipping has
removed.

Anyway, if that's the norm on this group, I'll try to comply. I object
though to being told that the method used here is an absolute for everyone.
It isn't, and a quick Google this afternoon shows that top and bottom
posting have roughly equal supporters, and most people are tolerant enough
to just live with the lack of a definitive judgement on it.

Mark


"Wally" wrote in message
. ..
Mark R Penn wrote:

Incidentally, top posting is a crime...................

No it isn't. I can see that in this group, the majority bottom post,
but in most others it's considered old fashioned and bad manners
nowadays.

In *most others*?? Did you check them all?


To bottom post forces the users of most newsreaders to
scroll all the way down to the bottom of a message to see the reply, ...

Only when the respondent is too dumb to operate their delete key.


--
Wally
www.artbywally.com
www.wally.myby.co.uk

Mark R Penn wrote:

In *most others*?? Did you check them all?

My apologies - should have said most others I subscribe to, mostly MS
PC based ones.

Thanks.


Only when the respondent is too dumb to operate their delete key.

Which removes the context for others.

Where do I say that the point being replied to should be deleted? In my
experience, the only practical way to keep stuff *readable* is to snip stuff
that you aren't responding to, and for your responses to the remainder to be
interleaved. Anything else is indicative of laziness, stupidiy, and the
arrogance to think that the reader has nothing better to do that scroll up
and down like a dummy, checking each new comment against each replied-to
comment, point-by-point.


... yet still leave the full context below for everyone else.

The full context, should I wish to read it, is in the previous post.


That avoids the issue where someone replies to a thread after
the messages have been removed from the servers, and all you see is a
single message with "" in the subject. ...

How many posts back to we go? Do you propose the everybody quotes every post
in the entire thread/branch, just in case something ages out on a server?


--
Wally
www.artbywally.com
www.wally.myby.co.uk