[Scott[_6_]]

On Jun 13, 10:48=A0am, wrote:
This week's stereophile in its online offerings has a gem of an article.

'AudioQuest Headquarters Tour'

http://www.stereophile.com/content/a...dquarters-tour

If one would want to produce subjective results guaranteed, the "tests"
described at the wire company could not have been setup more perfectly.

See if you can spot the obvious flaws in the "tests"? =A0Extra points for
those who spot the attempts to vaccinate the author's remarks against
these flaws?

For an even more interesting question, why did they bother when the
outcomes were predictable? =A0Might it have something to do with trying t=
o
vainly evoke science in support of a marketing department?

The obviosu problem with the first demo is that while on the surface
it may appear to be blind it is in fact not entirely blind. Even if
one does not know which is A and which is B one does know that one of
them is Audioquest and one of them is cheap no name cable. So the
listener does know what A and B are just not which is which. So it's
hardly proof of audible differences to claim one heard a difference
between A and B. This little bit I found to be interesting fro JA

"Quote:
One controlled blind test would suffice, thank you very much.

Michael Fremer and I independently took part in a blind test organized
by a Wall Street Journal editor at a CES a few years back. When the
scoring was analyzed after the test, it appeared that each of us could
distinguish between the cables by listening. Interestingly, neither of
us knew we were listening to cables when we took the test. Instead we
were under the impression that the test was investigating lossy
codecs.



John Atkinson

Editor, Stereophile"

[Audio Empire]

On Thu, 16 Jun 2011 19:41:56 -0700, Scott wrote
(in article ):

On Jun 13, 10:48=A0am, wrote:
This week's stereophile in its online offerings has a gem of an article.

'AudioQuest Headquarters Tour'

http://www.stereophile.com/content/a...dquarters-tour

If one would want to produce subjective results guaranteed, the "tests"
described at the wire company could not have been setup more perfectly.

See if you can spot the obvious flaws in the "tests"? =A0Extra points for
those who spot the attempts to vaccinate the author's remarks against
these flaws?

For an even more interesting question, why did they bother when the
outcomes were predictable? =A0Might it have something to do with trying t=
o
vainly evoke science in support of a marketing department?

The obviosu problem with the first demo is that while on the surface
it may appear to be blind it is in fact not entirely blind. Even if
one does not know which is A and which is B one does know that one of
them is Audioquest and one of them is cheap no name cable. So the
listener does know what A and B are just not which is which. So it's
hardly proof of audible differences to claim one heard a difference
between A and B. This little bit I found to be interesting fro JA

"Quote:
One controlled blind test would suffice, thank you very much.

Michael Fremer and I independently took part in a blind test organized
by a Wall Street Journal editor at a CES a few years back. When the
scoring was analyzed after the test, it appeared that each of us could
distinguish between the cables by listening. Interestingly, neither of
us knew we were listening to cables when we took the test. Instead we
were under the impression that the test was investigating lossy
codecs.



John Atkinson

Editor, Stereophile"

Wouldn't you be inclined to say that too if some of your largest advertisers
were "high-end" cable makers. I think so. First of all to avoid ****ing them
off and of course, if they got angry enough to pull their ad from your rag,
goodbye $$$$. In all things, follow the money. It (almost) always leads to
the truth these days.

[Arny Krueger]

"Scott" wrote in message
...
On Jun 13, 10:48 am, wrote:
This week's stereophile in its online offerings has a gem of an article.

'AudioQuest Headquarters Tour'

http://www.stereophile.com/content/a...dquarters-tour

If one would want to produce subjective results guaranteed, the "tests"
described at the wire company could not have been setup more perfectly.

See if you can spot the obvious flaws in the "tests"? Extra points for
those who spot the attempts to vaccinate the author's remarks against
these flaws?

For an even more interesting question, why did they bother when the
outcomes were predictable? Might it have something to do with trying to
vainly evoke science in support of a marketing department?

The obviosu problem with the first demo is that while on the surface
it may appear to be blind it is in fact not entirely blind. Even if
one does not know which is A and which is B one does know that one of
them is Audioquest and one of them is cheap no name cable. So the
listener does know what A and B are just not which is which. So it's
hardly proof of audible differences to claim one heard a difference
between A and B. This little bit I found to be interesting fro JA

"Quote:
One controlled blind test would suffice, thank you very much.

Quote: John Atkinson

Michael Fremer and I independently took part in a blind test organized
by a Wall Street Journal editor at a CES a few years back. When the
scoring was analyzed after the test, it appeared that each of us could
distinguish between the cables by listening. Interestingly, neither of
us knew we were listening to cables when we took the test. Instead we
were under the impression that the test was investigating lossy
codecs."

More details of this test can be found at:

http://online.wsj.com/article/SB120044692027492991.html

Two words - single blind

There was no double blind evaluation.

[Rob Tweed]

I've been wondering whether, if you look at the issue the other way
round, there's a minimum standard of cable beyond which there are no
discernable differences?

In other words, if you look at the cheapo end of the cable market
instead, as you get cheaper and crappier, is it reasonable to assume
that at some point you *will* hear a deterioration in sound? If so,
what are likely to be the criteria that dictate this point at which
discernable degradation occurs?

Rob

---

Rob Tweed
Company: M/Gateway Developments Ltd
Registered in England: No 3220901
Registered Office: 58 Francis Road,Ashford, Kent TN23 7UR

Web-site: http://www.mgateway.com
Twitter: @rtweed

[bob]

On Jul 13, 5:15=A0pm, Rob Tweed wrote:
I've been wondering whether, if you look at the issue the other way
round, there's a minimum standard of cable beyond which there are no
discernable differences? =A0

Sure. You can measure/calculate the effect that a cable will have on
frequency response within a given system. So long as that impact
remains below what is audible, there is no way to improve on that
wire--assuming that your standard is transparency, and you don't want
to use wire as a dumb equalizer.

In other words, if you look at the cheapo end of the cable market
instead, as you get cheaper and crappier, is it reasonable to assume
that at some point you *will* hear a deterioration in sound?

No, because "cheap" and "crappy" are not technical specs. For most
systems, the only thing that matters for speaker wire is that it not
be too thin for the lengths you are running. If your lengths are short
enough, the thinnest, cheapest, crappiest wire on the planet will do.
For patch cord/interconnects, you do need a minimal level of
robustness for the connections, but that's achieved pretty close to
the bottom of the market. Just don't spend any less than what
Monoprice charges, and you're probably good.

=A0If so,
what are likely to be the criteria that dictate this point at which
discernable degradation occurs?

Should be clear from the above.

bob

[Audio Empire]

On Wed, 13 Jul 2011 14:15:30 -0700, Rob Tweed wrote
(in article ):

I've been wondering whether, if you look at the issue the other way
round, there's a minimum standard of cable beyond which there are no
discernable differences?

In other words, if you look at the cheapo end of the cable market
instead, as you get cheaper and crappier, is it reasonable to assume
that at some point you *will* hear a deterioration in sound? If so,
what are likely to be the criteria that dictate this point at which
discernable degradation occurs?


You have to be careful there. If you wire-up a pair of very inefficient
speakers using long runs of 18 gauge wire (or smaller) you will definitely
hear a degradation of sound, but it is not due to the "quality" of the wire,
but rather its size. 14 Ga or larger is the rule of the day for speakers.

As far as interconnects are concerned, since they carry only small voltages
(10 volts, normally) at little current, wire size isn't so importa.t. In
fact, you could wire up your stereo from component to component with
coat-hanger wire and there would be no audible difference - even in a DBT.

[Arny Krueger[_4_]]

"Rob Tweed" wrote in message
...

I've been wondering whether, if you look at the issue the other way
round, there's a minimum standard of cable beyond which there are no
discernable differences?

Leaving out cables that are broken, I have to admit that I can't recall ICs
that were so bad that they had a bad effect on audio to an extent that would
be remotely audible.

In other words, if you look at the cheapo end of the cable market
instead, as you get cheaper and crappier, is it reasonable to assume
that at some point you *will* hear a deterioration in sound?

If you are talking about speaker wire, there's enough 24 gauge speaker wire
being sold to raise some concens.

24 gauge wire has about 24 ohms per 1,000 feet, which is 2.4 ohms per 100
feet of wire, or almost 5 ohms oer 100 feet of 2-conductor cable. That
means that a 20 foot 24 gauge speaker cable has 1 ohm of resistance which
can cause audible variations in the response of a typical 8 ohm speaker. It
is about as bad as a pretty good tubed amp in that regard!

[Kele]

I have some very old (well, 30 years anyway) RCA cable that still
work... and they are skinny, cheesy, and getting a little gummy.
Every now and then I bust these out to try something. I'm using some
right now while I test a pair of car speaker subs to assist the rear
channels of the home stereo. I'm leaning towards leaving the subs in
so the next thing I'll do is replace the cheesy wires with "better"
ones in the box of collected wires. I use the cheesy wires first
because they slip on and off the jacks easy and their skinniness just
makes them low hassle for experiments. Why do I feel the need to
replace the skinny wires with the turbine tipped variety that fit so
tight it takes several hands to hold everything down while plugging
these in? They're too tight (pain in the butt) and honestly I can't
hear a difference between skinny and turbine tipped. It's all in my
mind this one, and knowing that doesn't make the desire to swap the
wires subside. One thing about the turbine tipped wires is that none
have failed and they are "very old" and have gotten connected/
disconnected, boxed/unboxed, coiled/uncoiled many times. Do you think
my early 80's turbine tipped wires can be considered vintage? Even
though I have heard differences among wires (interconnect, speaker,
power), I feel the change in the sound they impart isn't necessarily
accurate. Sometimes the difference is beneficial so I leave them in
the chain where their "character" seems to help the overall. I do
think the skinny wires and turbine tipped ones actually affect the
sound the least so I feel these are accurate. The ones with character
are obviously more expensive. Some of the expensive ones sound like
the skinny ones (benign) while others have a personality. Shopping
for wires is, I consider, a crap shoot. How you gonna know if the
wire is going to sound neutral or have character? I wonder if it's
not so much the wire itself, but the interaction between components
and the wire that creates the character - like maybe differences in
resistance. This would explain the tester=92s who say there is no
difference between wires. If that's true, then we can't even shop for
wires based on reviews (other's experience) because their components
differ.

[Andrew Barss]

Audio Empire wrote:
: On Wed, 13 Jul 2011 14:15:30 -0700, Rob Tweed wrote
: (in article ):

: I've been wondering whether, if you look at the issue the other way
: round, there's a minimum standard of cable beyond which there are no
: discernable differences?

: As far as interconnects are concerned, since they carry only small voltages
: (10 volts, normally) at little current, wire size isn't so importa.t. In
: fact, you could wire up your stereo from component to component with
: coat-hanger wire and there would be no audible difference - even in a DBT.


Both good points, but they're distinct -- coat hanger wire is
(according to a quick GS) between 10 and 13 gauge, so it's not just usable
for line inputs, it can be used for speaker loads without degradation.


-- Andy Barss

[bob]

On Jul 15, 3:04=A0pm, Audio Empire wrote:

Corners ARE cut along the way. The "throw-away" interconnects such as tho=
se
sold forever by Radio Shack and included in the box with a lot of A/V
equipment, are next to worthless, not because they sound any different fr=
om =A0
a set of interconnects costing 10X, 100X, or even 1000X what they cost, b=
ut
because they a made so poorly.

Yeah, that's why two I/Cs I got with a tape deck in 1978 are still in
good working order. May we all be made so poorly.

bob

[Audio Empire]

On Mon, 18 Jul 2011 07:20:44 -0700, bob wrote
(in article ):

On Jul 15, 3:04=A0pm, Audio Empire wrote:

Corners ARE cut along the way. The "throw-away" interconnects such as tho=
se
sold forever by Radio Shack and included in the box with a lot of A/V
equipment, are next to worthless, not because they sound any different fr=
om =A0
a set of interconnects costing 10X, 100X, or even 1000X what they cost, b=
ut
because they a made so poorly.

Yeah, that's why two I/Cs I got with a tape deck in 1978 are still in
good working order. May we all be made so poorly.

bob


There are exceptions to every rule, and even the cheapest interconnects will
work forever if you never touch them - just hook 'em up once and forget 'em.

[bob]

On Jul 18, 8:56=A0pm, Audio Empire wrote:

There are exceptions to every rule, and even the cheapest interconnects w=
ill
work forever if you never touch them - just hook 'em up once and forget '=
em.

Actually, they were unplugged and reconnected numerous times as I
moved about (like back and forth between home and dorm rooms). And if
they ever fail, I've got a box of other freebies in the basement that
are as good as new. In my experience, the true exception is the
occasional I/C that fails. And I see no reason to believe that paying
more will necessarily avoid that problem. The people who make "high-
end" wires are dumb enough that there's no reason to assume they
understand the concept of strain relief.

bob

[Ed Seedhouse[_2_]]

On Jul 18, 5:56=A0pm, Audio Empire wrote:

There are exceptions to every rule, and even the cheapest interconnects w=
ill
work forever if you never touch them - just hook 'em up once and forget '=
em.

That was not true of Radio Shack speaker wire I purchased in the
1970's. It sounded fine, but eventually decayed and rusted to the
point where they would go intermittent and eventually just stop. The
sound quality was, so far as I could tell, identical right up to the
point they failed. I don't know the cause, but when a wire stops
conducting electricity you don't need a double blind test to know it!

After awhile they reformulated something and the wires worked fine as
long as I had them, but for awhile there were indeed problems. I
doubt if you could buy anything that would do this kind of things
these days.

[Audio Empire]

On Tue, 19 Jul 2011 03:54:35 -0700, bob wrote
(in article ):

On Jul 18, 8:56=A0pm, Audio Empire wrote:

There are exceptions to every rule, and even the cheapest interconnects w=
ill
work forever if you never touch them - just hook 'em up once and forget '=
em.

Actually, they were unplugged and reconnected numerous times as I
moved about (like back and forth between home and dorm rooms). And if
they ever fail, I've got a box of other freebies in the basement that
are as good as new. In my experience, the true exception is the
occasional I/C that fails. And I see no reason to believe that paying
more will necessarily avoid that problem. The people who make "high-
end" wires are dumb enough that there's no reason to assume they
understand the concept of strain relief.

bob


Actually, I had so much trouble with molded RCAs from Radio Shack over the
years (when I used record a major symphony using my "pro-sumer" 15ips, 1/2
track Sony 880P tape deck on Sony FeCr reel-to-reel tape. The Sony I/O was
RCA jacks) that I'm very quality conscious about interconnects. I don't care
about the sound of cables because, if the cables are doing their jobs, -
there is none. But I look at strain relief and connector quality very
carefully. I'm convinced that build-wise, one can only equal the "My Cable
Store" brand, but it would be hard to surpass it. They're inexpensive, use
good quality REAL RG-59 wire and seem pretty much indestructible.

[Audio Empire]

On Tue, 19 Jul 2011 03:55:56 -0700, Ed Seedhouse wrote
(in article ):

On Jul 18, 5:56=A0pm, Audio Empire wrote:

There are exceptions to every rule, and even the cheapest interconnects w=
ill
work forever if you never touch them - just hook 'em up once and forget '=
em.

That was not true of Radio Shack speaker wire I purchased in the
1970's. It sounded fine, but eventually decayed and rusted to the
point where they would go intermittent and eventually just stop. The
sound quality was, so far as I could tell, identical right up to the
point they failed. I don't know the cause, but when a wire stops
conducting electricity you don't need a double blind test to know it!

The radio shack speaker cable was standard copper AFAICS, Copper doesn't
rust, but it does corrode (the bare ends eventually get a blue-green coating
of crud on them especially in very humid environments.) You can cut the
corroded ends off and re-strip enough to reconnect, but what you really need
to do is to use a good terminations that form gas-tight connections, then the
part of the cable that connects the signal won't corrode.

After awhile they reformulated something and the wires worked fine as
long as I had them, but for awhile there were indeed problems. I
doubt if you could buy anything that would do this kind of things
these days.

Copper is copper.

[Arny Krueger[_4_]]

"Audio Empire" wrote in message
...
On Tue, 19 Jul 2011 03:55:56 -0700, Ed Seedhouse wrote
(in article ):

The radio shack speaker cable was standard copper AFAICS, Copper doesn't
rust, but it does corrode (the bare ends eventually get a blue-green
coating
of crud on them especially in very humid environments.) You can cut the
corroded ends off and re-strip enough to reconnect, but what you really
need
to do is to use a good terminations that form gas-tight connections, then
the
part of the cable that connects the signal won't corrode.

I've seen cables that have corroded far more quickly and severely than
others. A 250 roll of 12 gauge fine stranded low voltage wire I bought about
a decade ago was particularly bad. I attribute the difference to the
formulation of the plastic insulation.

The corrosion doesn't hurt performance, but it does make termination a lot
more work.

[bob]

On Jul 19, 9:20=A0pm, Audio Empire wrote:

Actually, I had so much trouble with molded RCAs from Radio Shack over th=
e
years (when I used record a major symphony using my "pro-sumer" 15ips, 1/=
2
track Sony 880P tape deck on Sony FeCr reel-to-reel tape. The Sony I/O wa=
s
RCA jacks) that I'm very quality conscious about interconnects. I don't c=
are
about the sound of cables because, if the cables are doing their jobs, -
there is none. But I look at strain relief and connector quality very
carefully.

Well, you're looking at this from the point of view of a professional
(or maybe semi-pro) recordist, who's going to be setting up and
breaking down systems pretty regularly. Yeah, strain relief is REALLY
important in that case. And spending a little money on a brand you can
rely is would definitely be worth it.

The home hifi hobbyist has different needs, and those needs can often
be met by the freebie I/Cs that come with gear--esp. since you get a
new one every time you buy a new component, so backups are always
available. Every freebie I've ever gotten has outlasted the component
it came with.

bob

[Audio Empire]

On Tue, 19 Jul 2011 03:54:35 -0700, bob wrote
(in article ):

On Jul 18, 8:56=A0pm, Audio Empire wrote:

There are exceptions to every rule, and even the cheapest interconnects w=
ill
work forever if you never touch them - just hook 'em up once and forget '=
em.

Actually, they were unplugged and reconnected numerous times as I
moved about (like back and forth between home and dorm rooms). And if
they ever fail, I've got a box of other freebies in the basement that
are as good as new. In my experience, the true exception is the
occasional I/C that fails. And I see no reason to believe that paying
more will necessarily avoid that problem. The people who make "high-
end" wires are dumb enough that there's no reason to assume they
understand the concept of strain relief.

bob


WEll, I've had so many problems with RCA's over the years (my Sony 880P
"pro-sumer" tape deck that I used to record a local symphony orchestra with
at 15 ips, 1/2 track using Sont FeCr

[Audio Empire]

On Wed, 20 Jul 2011 06:32:10 -0700, bob wrote
(in article ):

On Jul 19, 9:20=A0pm, Audio Empire wrote:

Actually, I had so much trouble with molded RCAs from Radio Shack over th=
e
years (when I used record a major symphony using my "pro-sumer" 15ips, 1/=
2
track Sony 880P tape deck on Sony FeCr reel-to-reel tape. The Sony I/O wa=
s
RCA jacks) that I'm very quality conscious about interconnects. I don't c=
are
about the sound of cables because, if the cables are doing their jobs, -
there is none. But I look at strain relief and connector quality very
carefully.

Well, you're looking at this from the point of view of a professional
(or maybe semi-pro) recordist, who's going to be setting up and
breaking down systems pretty regularly. Yeah, strain relief is REALLY
important in that case. And spending a little money on a brand you can
rely is would definitely be worth it.

The home hifi hobbyist has different needs, and those needs can often
be met by the freebie I/Cs that come with gear--esp. since you get a
new one every time you buy a new component, so backups are always
available. Every freebie I've ever gotten has outlasted the component
it came with.

bob


I agree, Still, when really good cables are so inexpensive, why settle for
less when buying?

[KH]

On 7/20/2011 6:31 AM, Arny Krueger wrote:
"Audio wrote in message
...
On Tue, 19 Jul 2011 03:55:56 -0700, Ed Seedhouse wrote
(in ):

The radio shack speaker cable was standard copper AFAICS, Copper doesn't
rust, but it does corrode (the bare ends eventually get a blue-green
coating
of crud on them especially in very humid environments.) You can cut the
corroded ends off and re-strip enough to reconnect, but what you really
need
to do is to use a good terminations that form gas-tight connections, then
the
part of the cable that connects the signal won't corrode.

I've seen cables that have corroded far more quickly and severely than
others. A 250 roll of 12 gauge fine stranded low voltage wire I bought about
a decade ago was particularly bad. I attribute the difference to the
formulation of the plastic insulation.

The corrosion doesn't hurt performance, but it does make termination a lot
more work.


Let me guess - Carol wire from Home Depot? Been there, Green that...

Keith

[Sebastian Kaliszewski]

Dick Pierce wrote:
Audio Empire wrote:
The radio shack speaker cable was standard copper AFAICS,
Copper doesn't rust, but it does corrode

Actually, to be precise, the chemical process that causes
iron to rust is the same that causes copper to turn green:
the rersult is, in both cases, an oxide of the metal that's
formed the same way.

To be precise, copper oxide (copper(II) oxide to be even more precise) is black.
That green stuff is a result of further reactions, mostly with carbon, chlorine,
and sulfur compounds.

Both are covered under the broad
blanket of "corrosion," of which oxidization by atmospheric
oxygen is but one type. Yes, copper doesn't "rust" because
the oxides of sopper doen't look the same as the oxides of
iron ("rust" being derived from one or another word for
"red").

But, it's not that iron "rusts" and copper "corrodes" as
distinctly different processes: they're the same process
but with different names.

The similar (not same, as copper is not iron) process just makes copper black.


Then we have the case of wire turning green inside an
insulating jacket: it's still the same oxidization
reaction, but one that is, ahem, encouraged by a less-
that-ideal choice of plasticizers in the insulation.

Thats true that poorly chosen isolation causes sometimes quick deterioration of
the wire covered by it, but it's other elemnts than oxygen which make copper
green. There is of carbon and ofteh chlorine as well to make wires green.

Generally, plasticizers (the chemical that make plastic [n]
plastic [adj]) are pretty nasty. Dioctyl pthalate is one
that springs to mind and, hopefully springs right out again
quickly. A lot of these things are either sufficiently
volatile (meaning high enough vapor pressure) or unstable
under the unfluence of UV or ozone that the disappear,
the result being the plastic [n] is no longer plastice [adj]:
it gets brittle and crumbly, e.e., plastic that ain't so
plastic any more.

Quiz on Friday.


rgds
\SK

--
"Never underestimate the power of human stupidity" -- L. Lang
--
http://www.tajga.org -- (some photos from my travels)

[Audio Empire]

On Wed, 20 Jul 2011 18:35:31 -0700, Dick Pierce wrote
(in article ):

Audio Empire wrote:
The radio shack speaker cable was standard copper AFAICS,
Copper doesn't rust, but it does corrode

Actually, to be precise, the chemical process that causes
iron to rust is the same that causes copper to turn green:
the rersult is, in both cases, an oxide of the metal that's
formed the same way. Both are covered under the broad
blanket of "corrosion," of which oxidization by atmospheric
oxygen is but one type. Yes, copper doesn't "rust" because
the oxides of sopper doen't look the same as the oxides of
iron ("rust" being derived from one or another word for
"red").

Yes, I think we all know that. Only iron rusts. other metals corrode, but it
is all oxidation.

But, it's not that iron "rusts" and copper "corrodes" as
distinctly different processes: they're the same process
but with different names.

I see we have a a champion of the obvious in our midst. 8^)

Then we have the case of wire turning green inside an
insulating jacket: it's still the same oxidization
reaction, but one that is, ahem, encouraged by a less-
that-ideal choice of plasticizers in the insulation.

Certainly possible and I have seen the phenomenon,

Generally, plasticizers (the chemical that make plastic [n]
plastic [adj]) are pretty nasty. Dioctyl pthalate is one
that springs to mind and, hopefully springs right out again
quickly. A lot of these things are either sufficiently
volatile (meaning high enough vapor pressure) or unstable
under the unfluence of UV or ozone that the disappear,
the result being the plastic [n] is no longer plastice [adj]:
it gets brittle and crumbly, e.e., plastic that ain't so
plastic any more.

Like British car wiring from the late '50's and '60's

Quiz on Friday.

Looking forward to it.

[Ed Seedhouse[_2_]]

On Jul 20, 6:35=A0pm, Dick Pierce wrote:
Audio Empire wrote:
The radio shack speaker cable was standard copper AFAICS,

=A0 Copper doesn't rust, but it does corrode

Actually, to be precise, the chemical process that causes
iron to rust is the same that causes copper to turn green:
the rersult is, in both cases, an oxide of the metal that's
formed the same way. Both are covered under the broad
blanket of "corrosion," of which oxidization by atmospheric
oxygen is but one type. Yes, copper doesn't "rust" because
the oxides of sopper doen't look the same as the oxides of
iron ("rust" being derived from one or another word for
"red").

Copper oxide forms on the surfaces of exposed copper but it does not
fall away and stays chemically bonded to the underlying metal,
something like a form of natural anodizing perhaps.
Many government buildings have copper roofs that turn green
eventually, and it actually, as I have been told at least, helps
protect the underlying copper by keeping oxygen away from it. One
reason why copper used to be a popular choice before it got expensive.

The "Parliament Buildings" visible from the harbor of my home town,
Victoria B.C., are a good example of this. Probably most state
capital buildings in the USA also show this. Not sure if the dome of
your federal congressional building is copper clad, but if so that
would be another example.

In the case of my bad experiences with RS cable years ago I suspect
plasticizing agents as suggested. They used to get all gummy and
unpleasant. I don't remember if the copper had changed color, but I
believe coper oxide is an insulator so that might explain it failing
as a speaker connector.

There are actually two forms of copper oxides. And as pointed out in
(as I remember it) a further post the green patina is not from the
oxide, but from the effects of sulphides on the oxide after it has
formed. It must be true because that's what Wikipedia says. :-)

Ed

[Doug McDonald[_6_]]

On 7/22/2011 7:56 AM, Ed Seedhouse wrote:

There are actually two forms of copper oxides. And as pointed out in
(as I remember it) a further post the green patina is not from the
oxide, but from the effects of sulphides on the oxide after it has
formed. It must be true because that's what Wikipedia says. :-)



It could be sulfides or it could be a combo of water and carbon dioxide.
The green looks like Malachite, a copper carbonate-hydroxide.

Doug McDonald

[August Karlstrom]

On 2011-07-14 02:06, Audio Empire wrote:
You have to be careful there. If you wire-up a pair of very inefficient
speakers using long runs of 18 gauge wire (or smaller) you will definitely
hear a degradation of sound, but it is not due to the "quality" of the wire,
but rather its size. 14 Ga or larger is the rule of the day for speakers.

In a typical setup even a thinner wire like 2x1.5 mm^2 will suffice. For
instance, if you need two runs of four meter wire and your loudspeaker
impedance do not drop below 7 ohm even a wire as thin as 2x0.5 mm^2 will
suffice. In general, if the resistance of the wire is allowed to be no
higher than one percent of the (minimum) speaker impedance the minimum
cross-sectional area of the wire can be computed as

A = (1.68 * 10e-6 ohm m) * l / R_L

where l is the length of the wire and R_L the minimum impedance of the
speaker.


August