On Feb 21, 7:34=A0am, "Bill Noble" <nob...@nowhere.czm> wrote:
> you see, those who wish to believe there are no differences are just as
> religious in damming those who have made reasonable experiments to prove
> otherwise. =A0

This appears to just a personal attack on people who disagree with
you. It tends to convince me that you really are not rational about
this. But even given that you are right, (which you aren't) you have
not provided any evidence that they are wrong, nor any evidence that
reasonably designed wire makes any difference.

>There is nothing anyone could do, there is no possible test
> involving human subjects that will ever be found suitable to the
> non-believers. =A0

This is factually incorrect and shows that you don't understand how
science works.
All we require to make us reconsider our beliefs is a properly
conducted blind, or preferably double blind experiment that shows you
(or anyone else) can reliably detect such differences to a
statistically significant level. A real scientist can do such tests
fairly easily. Actually they've done it many times and the results do
not support your beliefs.

It is also a personal attack on those who disagree with you.

>So, let them use the cheapest cables from the trash can
> with rusty connectors if it pleases their sound pallette.

Now you set up a straw man, since no one has ever made such a
suggestion here.

Your whole argument seems to amount to "the people who disagree with
me are bad, therefore I am right". Rather silly.

"Bill Noble" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)

> you see, those who wish to believe there are no
> differences are just as religious in damming those who
> have made reasonable experiments to prove otherwise.

Simply not true and even libelous.

> There is nothing anyone could do, there is no possible
> test involving human subjects that will ever be found
> suitable to the non-believers.

It is not a matter of non-belief. It's a matter of failing to find something
that is suitable to believe in. Dilligent efforts have been made.

> So, let them use the
> cheapest cables from the trash can with rusty connectors
> if it pleases their sound pallette

How can someone who is sincere and honest say such a thing?

On Feb 21, 9:55=A0am, dave a <blkcatREMOVET...@gmail.com> wrote:
> On 2/21/2010 7:34 AM, Bill Noble wrote:

> I have no problem if you want to spend the money on fancy cables. =A0They
> look nice and make you proud of your system. =A0That's fine. =A0Just don'=
t
> claim the cables make any audible difference, they don't.

Well I have no objection to anyone making such a claim, but if they
make a point of discussing it in a public opinion forum they shouldn't
be surprised or upset when other people disagree with them. To get
angry and say bad things about those who disagree with your beliefs is
just verbal abuse, not reason.

"Audio Empire" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)

> Sure, interconnects, if they're at least 20 ft long, they
> will most assuredly degrade sound.

Simply not true. Constructing a blameless interconnect that is 20 or even 50
feet long is no a big problem.

> Speaker cables which
> are too long or of insufficient wire size for the length
> of the run or the power that they are carrying will
> likewise degrade the sound.

But, there is a lot of copper in the world and forming it into a good long
speaker wire is not rocket science.


<snip rest of post which seems just fine>

"Bill Noble" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)

> 2. years ago I had a summer job as a lab tech testing
> cables for a cable TV company - it didn't take much to
> change SWR with a freq sweep - the setup was a terminated
> cable, and a freq sweep generator, and the usual
> transformer to look at reflected energy versus input
> energy - a small void in the insulator would cause real
> problems.

I seem to recall that something like this was lab experiment number one in
EGR 225 - Fields and Waves.

The lecturer made it clear that transmission lines (cables) had to be
several wavelengths long for our observations to be relevant.

The wavelength of the high end of the cable TV band is a few inches, while
the wave length of the high end of the audio band is a few dozen miles.

miles... inches... which one relates to things happening in anybody's
listening room?

Bill Noble wrote:
> it comes around from time to time and it will never end.

It comes around from time to time because people are simply
not willing to reconcile the difference between their beliefs
and physical fact.
Let's deal with one of your points

> 2. years ago I had a summer job as a lab tech testing cables for a cable TV
> company - it didn't take much to change SWR with a freq sweep - the setup
> was a terminated cable, and a freq sweep generator, and the usual
> transformer to look at reflected energy versus input energy - a small void
> in the insulator would cause real problems. I am pretty sure that the issue
> with the worst cable is reflected energy but I am not set up to test it. I
> can tell you for sure that a 6 inch length of it (the bad cable) made a
> decent CD player sound horrible, and changing it to pretty much anything
> else made it better.

I have no doubts that your experience and lessons learned
in testing cables for cable TV are valid. The question is
whether they have applicability to short audio interconnects.

The problem with a non-perfect termination (which an interruption
in a cable insualtion could certainly cause) comes, as you suggest,
from a reflection.

At 500 MHz and a 1 meter (3 foot) cable, this could be a serious
problem. Assume a cable velocity factor of 0.5, that 1 meter
cable at 500 MHz is over 3 wavelengths long, and a refelection at
the right (wrong) place can lead to actual, measureable and
substantial signal degradation. Even 6 inches long, that's a VERY
large portion of a single wavelength, which, at 500 MHz, is on
the order of about a foot or so.

Let's look at that same cable at, oh, 10 kHz. The wavelength in
the cable (assuming the same 0.5 velocity factor) is a mere 15
KILOMETERS in length. That means your 6 inch (0.2 meter) cable
is on the order of 0.000013 wavelengths long.

So, let's assume that your insulataion flaw reflect a whopping
10% of the energy. And it's halfway down the cable, And let's,
for laughs, assume you also have a bad mismatch at the end
(you do), which also reflects 10% of the incoming energy. That
means 10% gets reflected back to the end, where 10% of that
get's reflected back to the flaw, and 10% of that get's re-
reflected, and so on.

So how long does this keep bouncing around the system until it
gets reduced to insignificant levels? Well, let's call
insignificant to be less than the best-case noise level of the
CD, around -100 dB. That's 5 reflection (since the energy
reflected each time is 20 dB below the incident energy), and in
your 6 inch cable, that's all over and done with in less than
one BILLIONTH of a second.

Okay, let's assume 90% (alomst all) of the energy is
reflected. How long until THAT get's reduced to the same
level of insignificance? Well, each reflection loses only
about 0.9 dB, we need about 111 reflectsion to get it
reduced by 100 dB, and that takes under 15 billionths of
a second.

Now, are you suggesting that there are mechanisms in human
hearing that are capable of detecting decay phenomenon of
this type over periods lasting up to 15 nanoseconds,
corresponding to frequencies in the many Megahertz realm,
at intervals that correspond thousands of time smaller than
the sample interval of the CD player? Intervals over which
the very sound you're listeing two travels a mere 2 ten-
thousandth of an inch? Really?

Here's the point:

IF you are claiming that the same SWR phenomenon that's
responsible for poor performance of cable TV transmission
at 500 MHz is also the mechanism behind the performance
of your 6 inch cable at audio frequencies, as you seem to
be when you say:

"I am pretty sure that the issue with the worst
cable is reflected energy,"

then you have a large contradiction in the resulting
predictions the same SWR physics has.

How do you choose to reconcile that contradiction?

If you choose to ignore it, might I suggest that the
contradiction will, in your words "come around from
time to time and it will never end"?

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

On Mon, 22 Feb 2010 06:04:51 -0800, Bill Noble wrote
(in article <(E-Mail Removed)>):

>> Not so that anyone can measure or so that anyone in a bias-neutral test
>> procedure can hear.
>>
>
> one more point, for consideration - this is a very old experiment, well
> documented. I tried to duplicate it in the 60s but didn't make a good enough
> bandpass since I had no budget for parts and used what I could find. It is
> in many of the text books I read, certainly it can be found in peer reviewed
> literature..
>
> put on a pair of headphones. feed both channels with white noise from a
> single white noise source. you hear "hissssss". now, add a bandpass filter
> and a phase inverter so that you invert the phase of the signal in the
> passband only, and the rest remains as it was before. If done right, you
> can listen to the output and hear "hissssss" - because it's still pure white
> noise, indistinguishable from the original one. Now, put the original white
> noise into one channel of the headphones, put the modified white noise into
> the other channel and listen. What do you hear?
>
> no, you do not hear hisssssss. you hear the hisss with a strong tone at the
> passband frequency.
>
> now, explain that using only measuring instruments applied to the signal
> sources only.

That's easy. It's phase difference. At some point the phase of some frequency
is is shifted by the bandpass filter enough so that it doesn't completely
cancel out when inverted. A spectrum analyzer should be able to easily show
this.

> My point is that if you believe that audio = 2-20Khz sine wave response
> only, you are just plain wrong.

I don't remember anyone making that claim. Perhaps I missed something.


> The human ear processes frequency (arguably
> via a neural equivalent of an Forier Transform) and it processes phase
> information. The measurements described do not account in any way for phase
> distortion - at least none of the ones I've heard described.

I agree. But something has to cause enough "phase distortion" to cross the
ear's threshold of detectability (whatever that may be) and there isn't
anything in a meter or so length of cable that could cause such a phase shift
of even a small fraction of one degree at audio frequencies. But let us
assume, for the sake of discussion, that there were enough phase shift in the
audio passband caused by a cable to be audible. Wouldn't that show up in a
double-blind listening test? Could you not see such a shift using square
waves and an oscilloscope?

Bill Noble wrote:
> My point is that if you believe that audio = 2-20Khz sine wave response
> only, you are just plain wrong.

What do you mean "2-10kHz sine wave response?" By itself, it's
sufficently vague as to be essentially useless as a definition.
If you want to argue againsta useless strawman, have at it, you
won't get any onjection against those who aren't paying any attention.

Butyour implication that your "2-10 kHz sine wave response" ignores
phase information is, itself, "just plain wrong."

Taking, for example, the headphones in your proposed experiment
as an example, if you were to obtain what I believe you mean as
the amplitude vs frequency response, there is enough information
to completely construct the phase response of the system as well.

Thus, your statement is, in and of itself, "just plain wrong"
as a generalization.

> The human ear processes frequency (arguably
> via a neural equivalent of an Forier Transform) and it processes phase
> information.

So, you invoke Fourier analysis to support your position, yet,
above, you effectively reject Fourier synthesis, since any
finite signal that can be broken down into its sine-wave Fourier
components can also be created with the same sine-wave components,
yet you claim that the concept of 2-20 kHz sine wave response is
just plain wrong.

Which is it?

> The measurements described do not account in any way for phase
> distortion - at least none of the ones I've heard described.

Yes, you're right: you have either failed to describe
the proper measurements, or you have failed to properly
describe the measurements.

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

On Mon, 22 Feb 2010 06:06:20 -0800, Arny Krueger wrote
(in article <(E-Mail Removed)>):

> "Bill Noble" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)

>
> Two problems:
>
> (1) Most comparisons between interconnects don't involve the best and the
> worst. They are comparisions of two adequate and blameless items.
>
> (2) Just because there is a measured difference is not proof of an audible
> difference. It is all about quantificaiton and relevance.

Boy is that statement true! In the latest issue of the British magazine,
"Hi-Fi News" , there is a 'shootout' between different interconnects. For
each interconnect in the survey, they list all the pertinent facts: Shunt
capacitance, inductance, DC resistance, etc. The problem is, there is
absolutely no correlation between these specifications and the ranking given
these interconnects by the magazine. One would think that those interconnects
with the lowest impedance across the audio bandpass would affect the "sound"
of the cable (if any!) the least. But the results don't show that to be the
case at all.

On Mon, 22 Feb 2010 06:03:52 -0800, Bill Noble wrote
(in article <(E-Mail Removed)>):

> "Audio Empire" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> On Sun, 21 Feb 2010 07:34:44 -0800, Bill Noble wrote
>> (in article <(E-Mail Removed)>):
>>
>>> you see, those who wish to believe there are no differences are just as
>>> religious in damming those who have made reasonable experiments to prove
>>> otherwise.
>>
>
> two points, then I will stand down on this discussion - it comes around from
> time to time and it will never end.
>
> 1. when doing the testing of these cables in my living room, I had swapped
> from one cable to another (these were all 3 meter cables, XLR connectors,
> from preamp to power amp), and was listening again - I had been using one
> set for most of the day. my daughter (about 15 at the time) had been
> outside, walked into the room, stopped, and said "you changed the cables
> again, I liked the other ones" - now she did NOT see me change the cables.
> Yes, this is not a fully controlled test, but it might just hint at the
> reality of this.
>
> 2. years ago I had a summer job as a lab tech testing cables for a cable TV
> company - it didn't take much to change SWR with a freq sweep - the setup
> was a terminated cable, and a freq sweep generator, and the usual
> transformer to look at reflected energy versus input energy - a small void
> in the insulator would cause real problems. I am pretty sure that the issue
> with the worst cable is reflected energy but I am not set up to test it. I
> can tell you for sure that a 6 inch length of it (the bad cable) made a
> decent CD player sound horrible, and changing it to pretty much anything
> else made it better. Everyone who has listened to this cable (and I've
> made reasonably blind tests, not perfect by any means) hears it as
> defficient.

I won't address the first point. It's anecdotal and who knows what the entire
story is (not that you are trying to mislead us, but there are so many
variables involved in a scenario such as the one above, that I cannot even
attempt to second guess it).

The second one is easy. Cable TV works in the VHF and UHF range. At these
frequencies, even relatively short runs of coax can affect the signal
enormously. You have to deal with VSWR, skin effect, signal attenuation from
cable capacitance and cable inductance as well as plain old cable resistance.
In addition, you have ringing, waveform distortion (for instance, square wave
in, differentiated or integrated waveform out the other end). IOW, a whole
slew of parameters that makes it a modern miracle that cable TV outlets can
push an RF signal through miles and miles of cable and make it work AT ALL.
But none of this is transferable to audio. Audio frequencies are so low that
things such as cable capacitance and inductance, which are HUGE at VHF and
UHF frequencies are so insignificant at audio frequencies that in the case of
most domestic interconnect runs ( a meter or so), they are not even a factor.