Mains Cable confusion?

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Anonymous

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When the first Fostex DAT machine came into the country, we did a master simultaneously on DAT and half inch at 30 ips. We thought it would be the end of tape....until we listen back. JItter was such a serious problem that a whole procedure for measuring it and reducing it was develped. Jitter messes with the timing of the audio signal- the best I can describe bad jitter is that its like feeling disorientated and sea sick. I dont have an axe to grind on this one, but I do enjoy musical experiences better than cheese grated sound - its (like) the difference between Radio 3 FM and DAB sound.
 
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Anonymous

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candycable:OK - but pragmatically, when you are running a news feed from some event and you have a two hundrend metre run froim the source to the transmission van, the stranded CAT5 cable might bring the system down, where as the solid still hold up- I've been there. CAT 5E cable caN make good installation microphone and AES cable by the way..now that's not in the performance standards book!.
I'm not surprised you had problems, since the standard is 100m so you were operating well outside it.
 

idc

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candycable:When the first Fostex DAT machine came into the country, we did a master simultaneously on DAT and half inch at 30 ips. We thought it would be the end of tape....until we listen back. JItter was such a serious problem that a whole procedure for measuring it and reducing it was develped. Jitter messes with the timing of the audio signal- the best I can describe bad jitter is that its like feeling disorientated and sea sick. I dont have an axe to grind on this one, but I do enjoy musical experiences better than cheese grated sound - its (like) the difference between Radio 3 FM and DAB sound.

What level of jitter would you say is no longer audible?

I would say that another cable red herring is to find a problem with a cable at 100m and then claim it is also so with a 1m one.
 
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Anonymous

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Don't worry Grottyash It wasn't an ethernet application - it was audiomatix which can use CAT5 cable as a carrier. The point it to illustrate the different attributes of certain techniques and how they influence or impinge on performance. We used a similar system for the Commonweatlth games but in that case had to use fibre as the carrier as the runs were over 400m for that application.

In broadcast lots of applications use cables originally designed for a specific applications- including giants like Yamaha. The man****aturers will normallyspecify a type of cable and limits according to datarates they use and tolerance thresholds.
 
A

Anonymous

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Absolutely - two different scenarios. Like all systems
cable has an inductive, capacitive and resistive element. On a short cable these
elements will have a less dominance, and will be far less in proportion to the
LC and R of the input and output it is serving. On longer runs the LCand R of
the cable becomes more dominant and the overall circuit changes. (It is a
mistake to look too much at cable in isolation as there is interaction between
cable and components).
About Jitter- I can't remember the figures the studios used
to work to- but of course its the less the better. The truth is the entry level
is very high now compared to when the technology hit the streets. At first the
clocking was straight of the data stream coming from the head cylinder- so you
were subject to the inconsistencies of magnetic pulses on tape and revolving
drums for your clocking -not nice. The fact is the opposite of good these days
is excellent, that's to say the entry threshold is higher. It's in stability of
the imaging that jitter shows up most, and it, for me, is one of the big
arbiters of whether the sound is natural and real or sharp and unmusical A comparative
listen between and an excellent recording broadcast on Radio 3 FM and on DAB
can exemplify this – the FM has the hiss and crackle and is technically less
linear, but it sounds right, DAB is very clean but the image rarely has any
breadth or life to it- the signature of
compression and Jitter. Personally I like the Moon CD3.3 converter- they have
over sampled to kingdom come and re-clocked and it just images smoothly and
perfectly for my tastes.
 

idc

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This is a great thread
emotion-21.gif


So the killer question, CandyCable why do you think cables of all types fail blind tests when there are numerous reasons put forward as to how they can sound different, from jitter to directionality?
 

Clare Newsome

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Every blind test we've conducted with readers as part of our 'Big Question' features has involved them seeing and/or hearing differences wtih a range of cables.... In fact they didn't even know they were testing cables.
 
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Anonymous

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Hi GrottyaSh - that's a very abaolute statement you make there! However, if we didn't upgrade the mains cables in some of the broadcast studios and theatres I have been involved in, there would be some very noise broadcasts out there! Dimmer pack noise is just a biiger version of what switch mode power supplies do. Curretly I am working in King's College in Cambridge, and there is some serious RF knocking around their that does modulate onto anything it can - despite no regulations being busted- extreme, but it happens. That's the nature of life in electonics.

Actaully we often come across short coming or paradoxes in standards. one of the funniest was when a coulcil inspector (juniour new boy I might add) halted an installation becuase it breach the voltages for the low voltage directive. Why- becuase when the telephone rang its voltage peaked over the allowance...duhhh! He phoned his office and his senior told him to 'get real'.

You are right to some extent about the effect of pick up - whether RF of inductive as being one of the least evils.And usually RF is not the issue. Noise does accentuate or reduce a aprticular part of the audio band, but it does raise the noise floor. Noise sums to signal and alters the relative timing- a bit like jitter ( it a Nyquist thing). So you can loose some imaging with increase noise. You may hear it on a very well tuned system, but not your average comerical stuff. However, you miht see it on a TV picture as that info is right in the spectrum.

Induced noise tends to be far more dominant than 'stray RF' - it is a fact that we have to accomodate in large installations as really horrible and unacceptable noises and nasty imaging results if you don't combate it.
 

idc

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Clare Newsome:Every blind test we've conducted with readers as part of our 'Big Question' features has involved them seeing and/or hearing differences wtih a range of cables.... In fact they didn't even know they were testing cables.

WHF are the exception, all other blind cable tests I can find have been no better than random. I am not sure as to why that is.
 

Clare Newsome

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Neither can I, as I wasn't involved in the others. But i'm sure there's lots of informal blind-testing going on that enables people to make up their own minds as to what does/doesn't work for them in their system.
 

JohnnyV111

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"The Big Question" participants normally disagree about any differences and tend to use journalistic cliches obtained from the magazine to describe them. Surely if there were simply, for instance, "more bass" at least two panellists would claim there to be "more bass" and a simple spectrum analyser would confirm that there was "more bass." Why does it have to be so complicated?
 

Clare Newsome

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Because humans are involved. We all have different eyes, ears, preferences and ways of describing our experiences. For example, one person can describe something as 'harsh', another as 'revealing' - they're both hearing more detail, but that doesn't mean they both like it.
 

JohnnyV111

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Yes, but often they are apparently describing something completely unrelated to one another's experience, as is the case with the HDMI cable test which I have just re-read.

Then we get back to the idea of "try it for yourself in your system" - I can't drive but by the same token could offer consumer advice on car engine enhancements - I can't explain how they work, they may work better for some cars than others - go try them and get your money back if they don't work...
 

Clare Newsome

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Really? You're comparing cars with music/movies!

Though there is,I suppose, some simularity - the human factor. Ask our colleagues on What Car? or Autocar - they can have disagreements about cars as much as our team of testers can have about hi-fi/home cinema products. But that's precisely why we team test - so we can gauge a wide range of opinions and viewpoints before coming to an agreed verdict, based on having experienced an array of testing/test material.
 

JohnnyV111

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The car was a fairly random metaphor to illustrate that advice based on the principle of "try it for yourself and see" is non-advice and could as easily be provided by a non-informed person as otherwise.

The magazine offers specific advice on cables in reviews, but the content of "The Big Question," the non-advice on the forum, the unwillingness to provide something simple such as (for instance) screenshots of various cables providing "deeper blacks" or a straightforward scientific explanation of how high end cables work would appear to undermine the reviews.
 

professorhat

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Saying try before you buy is "non-advice" is ridiculous. Just because I'm informed on something and can give an opinion, that doesn't mean that opinion is correct for everyone. I loved the recent Star Trek film, but I'll bet there's a load of people who didn't. Suggesting that because I liked it, everybody should is plain silly clearly - someone needs to see it for themselves to make their own mind up.

In the case of these contentious cable threads, clearly there are people who can see and hear differences and people who can't - this is about the only thing which isn't up for dispute (rightly or wrongly and ignoring the whys and wherefores of how cables can possibly make a difference). With that in mind, advising someone to give something a trial prior to spending cash to see which group they fall in is clearly very good advice, rather than non-advice as you suggest.
 
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Anonymous

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candycable:
Hi GrottyaSh - that's a very abaolute
statement you make there! However, if we didn't upgrade the mains cables
in some of the broadcast studios and theatres I have been involved in,
there would be some very noise broadcasts out there! Dimmer pack noise
is just a biiger version of what switch mode power supplies do. Curretly
I am working in King's College in Cambridge, and there is some serious
RF knocking around their that does modulate onto anything it can -
despite no regulations being busted- extreme, but it happens. That's the
nature of life in electonics.

Actaully we often come across
short coming or paradoxes in standards. one of the funniest was when a
coulcil inspector (juniour new boy I might add) halted an installation
becuase it breach the voltages for the low voltage directive. Why-
becuase when the telephone rang its voltage peaked over the
allowance...duhhh! He phoned his office and his senior told him to 'get
real'.

You are right to some extent about the effect of pick
up - whether RF of inductive as being one of the least evils.And
usually RF is not the issue. Noise does accentuate or reduce a
aprticular part of the audio band, but it does raise the noise floor.
Noise sums to signal and alters the relative timing- a bit like jitter (
it a Nyquist thing). So you can loose some imaging with increase noise.
You may hear it on a very well tuned system, but not your average
comerical stuff. However, you miht see it on a TV picture as that info
is right in the spectrum.

Induced noise tends to be far more
dominant than 'stray RF' - it is a fact that we have to accomodate in
large installations as really horrible and unacceptable noises and nasty
imaging results if you don't combate it. I don't necessarily
disagree with you, but there's a world of difference between domestic
situations and broadcast studios/theatres where you're going to have
some pretty heavy duty equipment around. A one or two meter electrical
cable is going to have little impact, if any, on the noise you may, and
it's a big may, in the domestic environment, and even if it really
could then its not going to give you the type of improvements to bass,
timing, soundstage etc which some claim to hear.

It's quite
possible to test for mains noise as you'd be aware, but my instinct
tells me that 99% of people who buy exotic after market mains cables
never do, so it becomes a leap of faith.
I'm always surprised that
manufacturers and reviewers never publish scientific tests on mains
cables, since they're not that hard to conceive and carry out, and there
are some specialist labs around. Perhaps a grant to a research student
would be the way to go forward.
 
A

Anonymous

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I know there is a lot of cable out there with magic ingredients and some associated claim. As a
practical lad I ask questions' Why do you tap the cable 70 times? - Why exactly
do you add carbon to the copper? -( carbon is a bad conductor by the way)
Always the same answer ' the customer experiences a difference' Smoke and
mirrors? (you decide). It's really the only industry that gets away with it. I
was involved with a high tech probe cable for medical use- and also cable for
runway lighting (...it's special...) - Could I say that I dont know the technical
criteria is coverd but the customer experiences a difference? No - the end user
might just die!..

So I walked into a good dealer in my area and he has just
fired up an copy of Beethoven 7th, one I know well. It sounded muted and kind
of pulled into the wall behind the speakers. Not nice- but I did not know that
particular recording so I didn't judge. Then I looked round and saw the CD cover
was exactly the same pressing as the one I have - I immediately said to the
shop tec- 'There is something wrong'. It wasn't subtle. Assuming the CD's
DAC was up the creek (an advanced technical term) we skipped it and used the
amplifiers internal DAC. Problem solved, Beethoven was back and breathing
again. At that very moment, as if by magic, the UK distributor for the CD and
Amp walked in and said ' No the CD DAC should sound better than the Amplifier's
one'. Ah... So we switched back - the only variable remaining was the cable- so
out came a £8000 pair of interconnects and (not a sales pitch) in went a pair of
Ref Plus Interconnects. Bingo- Beethoven was back, and not just breathing, but
breathing with a twinkle in his eye. Seriously, the image came forward, opened
out and it sounded really natural again.

The word I would use to describe the difference - Stilted-
Natural.

The fact is I don't know how any heavily screened
interconnect can deliver timing detail because it inherently has such a large
propagation delay. That's why I stripped all the capacitive and inductive
elements out on the Ref Plus design. The audio band remains the same- and anyone can look with
a scope and try and spot an amplitude or distortion figure until they are blue
in the face- and there will be a small roll off at HF and hardly detectable magnetic bumps at LF - but its not that. When I started my bit on this thread I mentioned
how I was struck by being able to sit in the garden and point to a bird accuratly within
a few degrees without looking at it. To do that the ears differentiate the time
difference that the sound hits each ear to within a few micro seconds – way out of
audio band. It's called the Hass effect and its well established and
documented. (school maths - speed of sound, distance between ears, change of angle, change of relative distance (Tangents, Cosines etc)= change of timing= minisle)

Once that timing is lost in recording or playback, the
sound is OK but the imaging goes flat. We are lucky these days – most good CD's
are mastered so as to give us precision of timing that is very close to the source.
If you have a really good DAC then there is only the delay in the cables that can
become the possible 'mist' and soften the timing accuracy.When there is jitter or whewre there is a different delay relative to the frequency (nromal in electroncs) then this minute tiing is scambled a bit

I did some work for producer Robin Millar – (I built a
studio for him). I was privileged to here the acetate - the original test
pressing -of Sade's first album 'Diamond Life' – I remember the incredible
depth, warmth and imaging it had. My partner bought me a copy on CD for a
birthday a few years back – I could not play it. It was flat, lifeless and just
not right. It turns out that it had been transcribed to 48kHz and then to 44.1
with no attention to re-clocking. Effectively the timing of the data was skewed –
or – as I would say- screwed. The audio measured superbly I am sure – but it
suddenly sounded flat. (That was done in the early days of transcribing, and
things are now (generally) taken care of much better, but …that's assuming the
mastering engineer knows what they are doing and doesn't have a hangover….)

People ask me if there really is a difference' and a I plant them in form
of my humble Arrow/ Moon combination with spot on timing cables and they say things like 'The drummer is
sitting there'…that kind of sums it up.

I can hear a difference when its good, but I can't
differentiate much between mediocre on mediocre and more mediocre. At the risk
of sounding arrogant- that might be why A/B tests are indistinguishable. Can you see the detail in the horzon through one mist any differently then you can throuw another eild of mist? No. Detail gone.You then grappleing with the less details, macro stuff. A very low capacitance
signal cable will sound better than a high capacitance. If two cables have more
or less the same physical build, they will have very similar electrical
characteristics. They will sound more or less the same. You have to break the
mold to get out of that. And once the detail is lost (due to high interlink capacitance
or dodgy balancing 'techniques'), its not going to be brought back by the
cleverest amp or speaker. But that's me- At the end of the day, you go to a
good – non pushy dealer and insist on listen to exactly what you want, or what
trusted opinion might suggest – and you makes your choice and you pays your
money.

Here are some extreme examples of cables defintly, absolutley having a big effect on sound…

Can you hear cable difference? The BBC uses Starquad mic
cable – they use it not because it sounds better, but because it bucks the RF
that the lighting dimmer pack chuck out. However, it has quite a high capacitance
so it rolls the HF quite a lot on mic signals on long runs, - on a 500m run on
a golf course you may have to out the 5k up a good 6dB . Of course you can hear
cable.

Modern PA systems at big concerts – you may have notices-
sound heaps better than, say, the pile of boxes that used to be used, say, 20
years ago. The clever, centrally hung speakers consists of an array of units
that all focus on specific areas of the audience. These very well defined 'rays'
of sound are controlled by a complex micro second sized delay system. In order
to work accurately and sound half decent, the speakers depend totally on a phase
coherent link to the amps. If that cable is compromised its virtually impossible
to get the system to right or to focus. You can hear cable.

I suppose you could say to the question 'Can you hear cable' – that it depends what
you're listening to and listening with.

The same goes for power cable - as covered in some earlier post - but its the same deal- Noise effectiley skews timing- reduce noise and the image is better. The only thing with power cables is whether the threshold of the dealys and noise in your system are below the threshold of any that a mains cable can help with.

Hope that is useful. I better do some real work now....
 

Clare Newsome

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JohnnyV111:

The car was a fairly random metaphor to
illustrate that advice based on the principle of "try it for yourself
and see" is non-advice and could as easily be provided by a non-informed
person as otherwise.

The magazine offers specific advice on
cables in reviews, but the content of "The Big Question," the non-advice
on the forum, the unwillingness to provide something simple such as
(for instance) screenshots of various cables providing "deeper blacks"
or a straightforward scientific explanation of how high end cables work
would appear to undermine the reviews.

Well that's where we're going to have to disagree, sadly.

We've made our views - based on blind testing in fixed conditions - very clear (either for or against) in our reviews.

The Big Question seeks to open up these questions to a wider audience, under more informal circumstances, just to get the debate rolling. For example, when people say there are no differences between HDMI cables, let's see what readers think.

The fact that different people see/hear things differently is perfect illustration of the need for everyone to make their own mind up. We're not just saying 'try before you buy' to be dismissive, but precisely because it can be so subjective!

And I know from previous experience with trying to print screenshots showing subtle differences that they're virtually impossible to effectively produce in either print or online (and that's before people randomly accuse you of Photoshopping them...
emotion-40.gif
)
 

JohnnyV111

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Professorhat- Wouldn't it strike you as a little odd if you were to buy Total Film magazine and some of the the reviews read "go and see for yourself?"

EDIT - This post refers to Professorhat's earlier example about opinions on films, and is not intended to imply that WHF magazine offer no opinions in magazine reviews which they clearly do. Apologies for any confusion.
 

Clare Newsome

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But we give our reviews definitive ratings - we write what we see/hear
emotion-40.gif
However, we know that some people disagree. Other opinions are available!
 

JohnnyV111

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Clare Newsome:But we give our reviews definitive ratings - we write what we see/hear
emotion-40.gif
However, we know that some people disagree. Other opinions are available!

Thanks for taking the time to provide some considered replies - that about wraps up this afternoon's discourse for me, too!
 

professorhat

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JohnnyV111:Professorhat- Wouldn't it strike you as a little odd if you were to buy Total Film magazine and some of the the reviews read "go and see for yourself?"

Of course. What WHF reviews have you seen where they say "go and listen to it for yourself"? With either publication, you're purchasing it for the opinions of the reviewers.

However, I wouldn't read that opinion and think "well they say this film is brilliant so it must be" or "they think this TV is brilliant so I'll go and buy it without thinking about anything else". There's always an understanding in these things that opinions differ (well, there is for most ordinary folk with common sense anyway).
 

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