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Questions:
Q1:
Why doesn't XLO use silver conductors for
its cables? Isn't silver better?
Q2:
How long can I run my speaker cables?
Q3:
Do my speaker cables both have to be exactly
the same length?
Q4:
If I need long runs of cable for my system,
which is better, to use long speaker cables
or long interconnects?
Q5:
What is the warranty on my XLO cables?
Q6:
Do I need a special type of cable to install
behind walls or construction?
Q7:
Why do all XLO cables have directional arrows?
Q8:
How are XLO cables terminated? Why use gold
plating? Why not nickel or rhodium, like
some other manufacturers?
Q9:
How do XLO cables sound? Are they warm?
Or bright? rolled-off or 'edgy'? What do
they sound like?
Q10:
Does bi-wiring really sound better?
Q11:
How long can I run an S-video cable?
Q12:
Dielectrics? What are they, and what difference
do they make?
Q13:
"XLO sure does have a lot of cables!
How do you tell them all apart?"
Q14:
Why aren't XLO's best cables shielded except
as a "special-order"option?
Q15:
Why does XLO use braided copper and foil
shielding? Why two layers? Why those two
materials?
Q16:
What is XLO's "Field-balanced"
Geometry, and what's so good about it?
Q17:
Does XLO build cables in custom lengths
or with custom terminations?
Q18:
Which type of video cable is better?
Q19:
I've read in the magazines that 75 Ohm characteristic
impedance matching is important in my system
and my cables. What does that mean? What
IS characteristic impedance? How does it
affect my System? Is it really all that
crucial?
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Answers:
Q1:
Why doesn't XLO use silver conductors for
its cables? Isn't silver better?
A1: Although
they're not all specifically voiced, this
is really three questions in one:
o Why doesn't XLO use silver?
o Doesn't silver work better?
o Doesn't silver sound better?
Let's deal with them one at a time:
First of all, the question
"Why doesn't XLO use silver?"
is misleading because, until just recently,
XLO did use silver conductors. These were
the silver conductors at the very center
of the "Precious Metal Composite"
conductor array in XLO's least expensive
speaker cables, XLO/VDO models ER-15 and
ER-16.
Both of these cables
used multiple layers of conducting
wire, each layer of a different effective
resistance, as a cheap and efficient way
of controlling "skin effect phase shift".
Because of its low DC resistance, silver
worked very well in that application, but
we would never use it in any of our better
cables.
Which brings us to the second part of the
question "Doesn't silver work better?".
Many people think that because of silver's
low resistance (it has the lowest internal
resistance of any natural metal) it ought
to be more conductive than other metals.
They also think that its presumed better
conductivity ought to make for better cables.
In fact, that's just not the case.
For one thing, in an audio or video application,
silver isn't consistently more conductive
than copper. Conductivity is the ability
to pass a current. For a DC current, conductivity
is exactly the opposite of resistance, and
if we were dealing with DC, silver's lower
DC resistance (it's 11% less resistive to
DC current flow than copper) really would
make it a better conductor. Music or video
signals aren't DC, though, they're AC, and
that makes a huge difference!
With AC currents, inductance becomes an
important consideration. Silver is inherently
more inductive than copper, and, when an
AC current is passed through it, its greater
inductive reactance creates a steeper AC
resistivity gradient between the center
and outside of a silver conductor than would
be the case in a copper conductor of exactly
the same physical characteristics. This
results in, among other things, significantly
higher "skin effect" phase shift
as compared to a copper conductor, and it
is an important contributor to the characteristic
"silvery" sound of most silver-conductor
cables.
If the issue were just resistance, it would
be easy to make silver and copper cables
equal: Copper has 11% more (DC) resistance
than silver, so just using copper cables
that are 11% shorter would make the resistance
exactly the same. The fact, though, is that
resistance simply isn't the issue!
Another thing that isn't the issue is cost.
People sometimes assume that because silver
coins are generally more valuable than pennies,
silver must be more expensive than copper.
That's not necessarily true: While ETP copper
(the stuff that pennies and household electrical
cables are made out of) is certainly cheaper
than silver (at about $0.68 as compared
to $4.65 per ounce), Laboratory Grade copper
(the specially processed high-purity copper
specified by XLO for use in all Reference2,
Signature2, UnLimited Edition and Limited
Edition cables) currently sells for as much
as $12.21 per ounce . This is more than
2 ½ times the price of silver, so
if silver really were any better than copper,
we would rush to use it.
Which brings us finally to the question
of "Doesn't silver sound better?"
We don't think so, but that's because we
don't think that cables should have any
sound at all!
Even people who like silver cables agree
that they have their own characteristic
sound. Silver cables tend to give everything
that passes through them a "shiny"
or "silvery" quality that might
be quite seductive, but that's NOT part
of the music or the sound that's actually
on the recording. That isn't what XLO is
all about. We believe that cables should
just pass signal from one point to another,
without adding, subtracting, distorting,
coloring, or in any other way imposing their
own voice on what you hear - even if the
change are, as with silver's characteristic
coloration, something that some people might
like better.
"Hi-Fi" is a contraction for
"High Fidelity", a term which
originally referred to a philosophy of sound
recording and reproduction that held to
"a high degree of fidelity (faithfulness)
to the actual sound of the original music.
That's still what XLO believes in, and that's
why we don't use silver in our cables.
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Q2:
How long can I run my speaker cables?
A2: In most
cases, resistance and inductance are the
two most important concerns when running
long lengths of speaker cable. Resistance
wastes amplifier power, and, if too high,
can actually lower your amplifier's effective
damping factor and limit its ability to
control your loudspeakers' drivers. Excessive
inductance can act like an audio "choke"
and limit and roll off high frequency response.
Capacitance can also be a concern, with
excessive capacitance limiting and "muddying"
bass response. Even so, the problem of too
much capacitance is less common than that
of too much inductance except in certain
"ribbon" (flat format) or other
cables designed with consideration only
for low inductance.
Resistance, inductance and capacitance
are all cumulative - the longer your cables,
the higher the total value for each - so
the best general rule is to keep your speaker
cables as short as possible.
Another general rule - especially for long
runs - is to use the "biggest"
(lowest numerical AWG gauge ) that you can
find. The bigger the cable is, the lower
the resistance will be. Beware, though,
of getting a speaker cable that's ONLY bigger.
There are many ways to make cables bigger,
and unless they are properly designed, bigger
cables can have more skin-effect phase shift
and actually make your speakers sound worse.
As long as good speaker cable is used,
which is properly designed and of an appropriate
AWG gauge , there is really no practical
limit on the length that speaker cables
can be run. Most homes, and even most movie
theaters, simply aren't big enough to require
cable runs long enough to pose a problem.
XLO speaker cables, at every price point,
are all designed for optimum performance,
even in the longest lengths ever likely
to be required. To be sure your system always
sounds as good as it can, always specify
XLO!
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Q3:
Do my speaker cables both have to be exactly
the same length?
A3: Unlike most
other manufacturers, XLO does NOT require
that its speaker cables be used in equal-length
pairs.
Some cables have a high resistance to current
flow (thin cables, many cheap or poorly
designed cables, and especially the surprisingly
high-priced carbon fiber cables from a certain
well-known European cable designer who really
ought to know better). High resistance speaker
cables can reduce your amplifier's effective
damping factor and limit its ability to
control your speakers' drivers. High resistance
can even produce audible differences in
speaker volume. If sufficiently unequal
length of these cables are used, uneven
speaker volume levels and inconsistent channel-to-channel
driver control can alter and unbalance stereo
imaging and instrument placement.
High inductance or high capacitance - both
found in some speaker cables (especially
those that feature flat "ribbon"
construction or "magic boxes")
- can act as filters or even resonant equalizers
and noticeably change speaker frequency
response and tonality. Where these effects
are present unequally because of differences
in speaker cable length, channel-to-channel
tonality will be skewed, depth and detail
will be lost, and stereo imaging will suffer.
Phase-shift effects in speaker cables arise
not only from "skin effect", but
also from resistive/capacitive (R/C) and
resistive/inductive (R/L) resonances within
the cables. Because these effects are cumulative
with length, different cable lengths for
the two stereo channels can, where these
effects are significant, cause audible problems.
XLO speaker cables simply don't suffer
from these problems. The result is that,
to a very substantial degree, different
length cables on your two stereo channels
just don't matter.
Regardless of different run lengths from
your amplifier, you no longer need to put
up with an unsightly coil of extra, unnecessary
cable behind one speaker. Even more importantly
where very expensive cables are used, you
no longer need to buy one cable longer than
necessary just because you do need the extra
length in the other. At tens or even hundreds
of dollars per foot for top quality speaker
cables, XLO's exclusive ability to allow
you to get good sonic results from unequal
length cables can amount to not just improved
"WAF" (Wife Acceptance Factor)
for your system, but to very real money
savings, as well!
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Q4:
If I need long runs of cable for my system,
which is better, to use long speaker cables
or long interconnects?
A4: The very
best thing to do is always to try to use
the very shortest cables possible for every
application.
Regardless of local fashion, neither the
use of long interconnects and short speaker
cables, nor of long speaker cables and short
interconnects offers any particular advantage,
and both have their associated problems:
Very long interconnects can pick up hum
and noise and require shielding or, where
characteristic impedance is crucial (as
is sometimes the case in digital or video
applications) they can result in heterodyning
and "dropouts." Very long speaker
cables can result in losses of signal level,
high frequency roll-offs, resonant effects
and loss of amplifier damping factor.
All of these things will affect the sound
of your system, and should be avoided whenever
possible. Try moving or rearranging your
system or your listening room or re-stacking
your electronics or putting them in a rack
or cabinet that will allow you to bring
them closer together, using shorter cables.
If none of these can be done, here's our
very best advice:
Choose the cable option that will cost you
the very least amount of money!
It's true, at least if the cables you're
using are from XLO: XLO cables are all engineered
to minimize the negative effects of use
in very long lengths, so just figure out
which will be less expensive -- long speaker
cables or long interconnects -- in the length
you require, and go with that.
In doing your calculations, be sure to remember
that XLO speaker cables can be ordered and
used in unequal-length pairs , and that
just that one thing could
save you a worthwhile amount of money.
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Q5:
What is the warranty on my XLO cables?
A5: All XLO
cables, from the very least expensive, all
the way up to the Limited Edition, are warranted
for the life of the product against damage
or failure due to defect of manufacture.
If any XLO cable ever fails because of any
manufacturing-related reason, just return
it to XLO and we will, at our option, either
repair or replace it and return it to you
absolutely free of charge.
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Q6:
Do I need a special type of cable to install
behind walls or construction?
A6: The answer
is a firm "yes", "no",
and "maybe", with the key being
the word being "need":
Most building codes require that any wiring
that will be built into a structure must
meet certain standards of fire resistance.
In the United States, the normal standards
are "CL-2" or "CL-3";
in Canada, it's "FT-4"; and similar
standards are in place in most parts of
the world. If you're talking about having
your home or office wired for sound as part
of new construction, and that construction
is going to have to be inspected and approved
in accordance with the local code, you probably
DO "need" to use cables that will
comply.
If you're running your wiring as a retro-fit
after the building is already up and approved,
but you're still worried about possible
electrical fire hazards, set your mind at
ease: Interconnects are always run at low
voltage and low current, so they simply
aren't a concern in that way. Even speaker
cables are run at low voltages (The absolute
MAXIMUM most amplifiers can ever put out
is around 50 Volts), so there's little danger
of sparking and even the least expensive
XLO cable, if intact, has insulation capable
of resisting voltages VASTLY higher than
it will ever see. In terms of heat resistance,
too, every one of XLO's Teflon-insulated
speaker cables will withstand temperatures
THREE TIMES HIGHER than is required for
CL-2 rating, so you DON'T "need"
to worry about using them in retrofit applications.
You don't "need" special "built-in"
cables from a performance standpoint, either.
All of XLO's cables will sound just as good
for built-in applications as they do when
used conventionally, so "maybe"
you ought to go to your friendly nearby
XLO dealer to check them out.
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Q7:
Why do all XLO cables have directional arrows?
A7: To indicate
which way the cables should be installed
for proper signal flow. The arrows should
always point from "source" to
"load", so interconnects will
have their arrows pointing from the CD player
(for example) to the preamp, or from the
preamp to the amplifier. Similarly, speaker
cables should always be installed so that
the arrows point from the amplifier or receiver
to the speakers.
Because XLO's two proprietary treatments
interact with the grain of the copper conductors,
all XLO cables are highly directional, and
all must be properly installed in order
to achieve their full performance capabilities.
If installed in the wrong direction, XLO
cables sound harsh. bright and "forward",
just the opposite of the effects that the
treatments are so famous for producing.
Another very important point on the directionality
of speaker cables: INSTALLING SPEAKER CABLES
WITH THE WRONG LEADS TO "HOT"
AND "GROUND" WILL ACTUALLY REVERSE
THEIR DIRECTIONALITY AND AFFECT THEIR PERFORMANCE.
IN ADDITION TO MAKING SURE THAT THE ARROWS
ARE POINTING IN THE RIGHT DIRECTION, ALWAYS
BE SURE THAT THE LIGHTER COLOR LEAD IS ATTACHED
TO THE POSITIVE ("HOT' or RED) TERMINAL
OF YOUR AMPLIFIER AND THAT THE DARKER COLOR
LEAD GOES TO THE NEGATIVE ("GROUND"
or BLACK) TERMINAL.
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Q8:
How are XLO cables terminated? Why use gold
plating? Why not nickel or rhodium, like
some other manufacturers?
A8: All XLO
cables are hand terminated using connectors
of XLO's own design, made from the very
best materials and dielectrics to XLO's
own rigorous standards. Audio interconnects
feature RCA, XLR or BNC connectors. RCA,
"S","F", and BNC connectors
are used for video. All connectors are non-magnetic,
and feature direct gold-plated contacts.
Speaker cables may be specified with "pin"
connectors, "standard" (6mm) spade
lugs, "large" (8mm) spade lugs,
standard banana plugs, "Deltron-style"
banana plugs, or Signature Series "Saf-T-Plug"
non-shorting banana plugs. All spade lugs
(except for the Limited Edition) are made
from CDA alloy 101 "four nines"
(99.994% pure) copper, and (except where
bare copper is specified), all are direct
gold plated, with no intervening layer of
nickel to spoil the sound.
We use gold plating just for cosmetics
and to keep the connectors' substrate metal
from oxidizing or corroding. Perhaps surprisingly,
gold is neither particularly good-sounding
nor a particularly good conductor. It's
only about 40% as conductive as copper and,
being highly subject to self inductance,
it's NOT recommended for ultra high frequency
applications.
Rhodium is another metal that some designers
use for cosmetics and to prevent corrosion.
Some claim that its "lattice-type"
molecular structure should allow it to pass
electrons more freely, but the fact is that
its conductivity is even worse than gold,
and its resistance is more than ELEVEN TIMES
as high as copper!
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Q9:
How do XLO cables sound? Are they warm?
Or bright? rolled-off or 'edgy'? What do
they sound like?
A9: Good questions!
Many cable brands have sonic characteristics
of their own that they impose on any signal
that passes through them. Sometimes it's
intentional, sometimes it's not, but it's
never right! XLO cables are different. We
believe that cables should be neutral -
that they should never add anything to,
or subtract anything from the signal, and
that they must never distort the signal
or modify it in any way.
That's XLO's design goal for every cable,
and within the limits imposed by budget,
materials and technology, that's what we
deliver: Our very best cables, the Limited
Edition come very close to this ideal of
perfection, and even our least expensive
cables have far less of a noticeable sonic
"signature" than any of their
competition. So what do XLO cables sound
like? The higher you go up the XLO line,
the less you hear of the cables, and the
more you hear of the sound of the music,
the recording, and the sound of your other
components. Even at the very lowest price
points, you hear more of what's actually
there than with any other brand. Isn't that
exactly what you want?
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Q10:
Does bi-wiring really sound better?
A10: Maybe.
Here's the story: In order to make their
products bi-wireable, speaker manufacturers
have to separate the "high-pass"
and "low-pass" elements of the
crossover. Then, once they've done this,
they have to do something to connect the
two elements back together, in case the
customer doesn't want to bi-wire them. To
make this connection, they generally use
a pair of stamped brass straps running between
the two sets of binding posts that the speakers
had to get in order to make them bi-wireable.
What they don't seem to realize is that
brass, among other nasty characteristics,
has only about 20 percent of the conductivity
of copper, and that those jumpers can hurt
the sound of the speaker if it is used wired
normally.
XLO believes that much or all of the improvement
that seems to come from bi-wiring may actually
come about just from removing those awful
brass straps. To that end, XLO offers jumpers
made of genuine VDO, Ultra, Reference2,
Signature 2, UnLimited Edition and Limited
Edition speaker cable with either spade
lugs (large or small) or banana plugs. In
most cases (except where [as we recommend]
two different "special" cables,
such as the combination ER-14 and ER-12
are used for special purposes), we believe
that jumpers sound every bit as good as
bi-wiring, and that using them can save
audiophiles a whole lot of money!
One thing that we know for certain about
bi-wiring is that CABLES NOT INTENDED TO
BE INTERNALLY BI-WIRED ("internal"
bi-wiring is making a "bi-wire"
set of conductors out of a single cable)
MUST NEVER BE USED IN THAT WAY: Each time
a conductor element is halved (as is done
in internally bi-wiring a cable not designed
for that purpose), its resistance is doubled;
its (AWG) gauge is reduced by three full
sizes; and its original conductor geometry
(which presumably was an important part
of its design) is lost completely. IN NUMEROUS
TESTS, INVOLVING CABLES FROM MANY DIFFERENT
MANUFACTURERS, WE HAVE NEVER HEARD A WRONGLY
BI-WIRED CABLE THAT SOUNDED EVEN AS GOOD
AS THE SAME CABLE USED AS IT WAS INTENDED
TO BE.
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Q11:
How long can I run an S-video cable?
A11: NO cable
manufacturer - not even XLO - recommends
using S-video for runs of more than 5 meters
(16.4 feet)
That's NOT to say that it can't be done
-- some of XLO's customers have reported
successfully using XLO/VDO model ER-1s S-video
cables for runs of as much as 80 feet (!)
-- What we DO say, though, is that it can't
be done with any degree of certainty: Among
the problems that can arise from using long
runs of ANY S-video cable is that "standing
waves" can develop along the length
of the cable. These are exactly like acoustical
standing waves, and come about as a result
of characteristic impedance mis-matches
between the two pieces of equipment and
the cable. If the length of cable you're
using is at or near the standing wave peak-to-peak
distance (which will vary with the length
of the cable and the amount and frequency
of reflected energy), you'll have problems,
like bars or diamond patterns on the screen.
Going either longer or shorter MIGHT solve
this: As with acoustical standing waves,
if you're between the wave peaks, everything
appears normal and transmission could be
completely unhindered.
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Q12:
Dielectrics? What are they, and what difference
do they make?
A12: To answer
that, let's first ask a different question:
Do you know what a capacitor is? Sure you
do: It's an energy storage device that's
formed when any two electrical conductors
(the "plates") are separated by
any non-conductor (the "dielectric").
"Charging" the capacitor is done
by passing current (of either positive or
negative polarity) through the conductors.
This results in some of the (signal) energy
being picked up and stored in the dielectric
and then dumped back (INTO THE SIGNAL PATH!)
when the polarity of the current changes.
In a cable, the dielectric is the insulating
material surrounding and separating the
conductors, and just like the dielectric
in a capacitor, it will pick up some of
the signal energy passed through the cable
and dump it back into the signal path (ALWAYS
OUT OF PHASE) when the signal polarity changes.
This storage and subsequent dumping of signal
energy changes the signal, and therefore
the sound of the entire system.
Poor quality or poorly chosen cable dielectrics
are often the reason why cables have a distinct
"sonic signature" when, really,
they should have no sound of their own at
all! For minimum sonic effect, the dielectric
in a cable must store as little energy as
possible, (It must have a low "dielectric
constant.") and it must return its
stored energy to the system in the smallest
possible increment of time. (It must have
a high "dump rate.") DuPont Teflon
has the lowest dielectric constant and the
quickest dump rate of any wire insulation
material now available, and it or Teflon
variants are the only dielectric or jacketing
materials used in any XLO/Ultra brand, Reference2,
Signature 2, UnLimited Edition or Limited
Edition cable.
The ethylene polymers and co-polymers used
in XLO/VDO brand cables (including proprietary
products like Elvax, Surlyn and Alathon)
are the next best thing to Teflon. These,
while much less expensive than Teflon, also
have excellent dielectric properties and
can offer outstanding cable performance.
The lowest performance dielectric materials
are PVC compounds, thermoplastic rubbers
and nylon. These are cheap, easy to use,
and tend to have a nice texture or "feel".
While many other manufacturers (including
some "High-End" brands) make extensive
use of these materials, XLO will only use
PVC for outer jacketing on its lowest cost
cables, and uses none of the other materials
for any purpose at all.
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Q13:
"XLO sure does have a lot of cables!
How do you tell them all apart?"
A13: The first
way to tell one XLO cable from another is
by color: Yellow is the official color that
the industry has adopted for video cables,
so most XLO/VDO cables have yellow on them
somewhere, and ALL VDO packaging has YELLOW
as part of its color scheme. For XLO's High-End
cables - Ultra, Reference2, Signature 2,
UnLimited Edition and Limited Edition --
the color is PURPLE. See? You're already
starting to become an XLO expert!
XLO's product numbering system is just
as easy as its colors: For every product
line EXCEPT VDO, all of the numbering follows
exactly the same pattern:
1 = Unbalanced interconnects (e.g. Ultra
1, Signature 1.2, etc.)
2 = Balanced interconnects (e.g. Ultra 2,
Signature 2.2, etc.)
3 = Phono cables (e.g. Reference2 Type 3a,
Signature 3.2)
4 = Digital cables (e.g. Ref2 Type 4a, Signature
4.2, etc.)
5 & 6 = Speaker cables (Ultra 6, Signature
5.2, etc.)
10 = Power cords (ER-10, Reference2 Type
10a, Signature 2 S2/10)
12 = Double run speaker cables (ER-12 and
Ultra 12)
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Q14:
Why aren't XLO's best cables shielded except
as a "special-order"option?
A14: Because
SHIELDING AFFECTS THE SOUND. Even shielding
done the right way (which is the only way
that XLO will ever do it) acts like an additional
capacitor, and creates "dump artifacts"
that will audibly change the sound of the
system. Done the way XLO does it (with insulated
overshielding spaced as far as possible
from the signal conductors and grounded
outside the signal path) the sonic effect
of shielding is minimal. Even so, to the
critical listener, it may still be audible,
if only very slightly. XLO recommends that,
for the very finest systems, shielding for
line level interconnects should not be used
unless severe EMI or RFI problems make it
necessary. If you must use it, though, USE
IT. It's far better to deal with tiny incremental
shielding losses than with large annoying
hum, noise and static problems. The proof?
All of XLO's phono cables (even the Signature
2 Type 3.2) are shielded, and the critics
still regard them as "The Best in the
World."
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Q15:
Why does XLO use braided copper and foil
shielding? Why two layers? Why those two
materials?
A15: By now
you should know that, because cable shielding
always affects the signal being transmitted,
it's always XLO's preference not to use
any shielding at all unless it's absolutely
necessary. When it IS necessary, though,
we DO use it, and we insist that what we
use must be the very best available. That's
why, for the most critical applications,
we choose both copper and foil shielding.
There are three reasons for this:
o Coverage
o Metal content
o Coverage bandwidth
Braided shields cannot by themselves ever
offer consistent complete coverage of the
conductors to be shielded. Braiding always
leaves gap areas next to the points where
the braided wires cross, and even "served"
shielding, , which can be applied so that
it initially offers 100% coverage will spread
apart and develop gaps at the point opposite
the point of greatest flexure whenever the
shielded cable is bent. Foil shielding has
no such coverage restriction, and can be
applied so that it provides and maintains
100% shield coverage. Although 100% shield
coverage is not necessary in all applications,
where it is required, XLO always uses at
least one layer of foil.
If you remember that shielding only works
when it is grounded, you'll understand that
"impedance to ground" is an important
consideration in every shielded cable design.
The object is to get the lowest possible
impedance to ground so that even the lowest-level
current can be effectively grounded. (The
lower the level of signal that can be grounded,
the more effective the shield will be.)
An important element of impedance is resistance,
and the more metal is in the ground path,
the lower the resistance - and therefore
the total impedance -- will be. Lowering
impedance to ground is one of the most important
reasons for ALL multi-layer shielding, and
using both copper braid and foil shielding
puts that much more metal in the ground
path.
The currents that are sent to ground from
the shield are the result of induction from
the collapse of electromagnetic hum and
noise fields surrounding the shielded cables.
Different shielding materials have different
induction characteristics and different
sensitivities to the induction of current
flow at different frequencies. Copper has
its best sensitivity to current induction
at one range of frequencies and aluminum
has its best sensitivity at a different,
but partially overlapping, range of frequencies.
By using both copper and aluminum in our
foil and braid shields, we ensure that our
cables will have the broadest possible bandwidth
of protection.
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Q16:
What is XLO's "Field-balanced"
Geometry, and what's so good about it?
A16: It's the
only cable geometry in the industry that
actually recognizes and takes advantage
of the physics of cable operation.
Whenever current is passed through a wire,
an electromagnetic field is formed around
the conductor. When the current-carrying
wire is insulated, an electrostatic field
is also formed around the insulation. Both
of these fields - the current-controlled
electromagnetic field and the voltage- controlled
electrostatic field affect the passage of
signal information, and can have a significant
effect on the sound of an audio cable. Many
cable designers have tried to deal with
one or the other of these field phenomena
(usually the electromagnetic field), but
until XLO, no one had ever recognized the
importance of both fields and of their interrelationship.
The fact of it is that there is only one
optimum relationship for the two fields,
and where that is present signal transmission
is materially improved.
Optimizing the relationship of the electrostatic
and electromagnetic fields is what XLO's
"field balanced" geometry is all
about. It's also why XLO cables look different
from everything else and even from each
other.
This is understandable if you consider
that different applications have different
current-to-voltage ratios, and that voltage
and current control the intensity of the
different fields. Phono cables pass very
tiny currents at equally tiny voltages;
line-level cables pass relatively very large
voltages with very little current flow;
and speaker cables need to be able to pass
very large currents at relatively small
voltages. With different current/voltage
ratios creating different relative field
intensities, but only a single optimum field
relationship, it's obvious that different
constructions will be necessary to achieve
the same point of balance, and that is exactly
what XLO has produced.
XLO's High-End cables are the first to
effectively deal with the physics of signal
transmission. That's why they seem to sound
so good. The fact, though, is that they
have very little "sound" of their
own at all -- what XLO users actually hear
and enjoy is the sound of the music!
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Q17:
Does XLO build cables in custom lengths
or with custom terminations?
A17: Maybe.
It depends on which cables you want, how
long you want them, and what kind of custom
termination you need. On our lowest-priced
cables we generally DON'T do custom lengths
or custom terminations, just because the
amount we would have to add for individually
making the cables to your special order
would probably be enough to make you not
want them! On our better cables, though,
(XLO/Ultra, Reference2, Signature 2, UnLimited
Edition, Limited Edition, and even some
products in the XLO/VDO and XLO/Pro lines)
custom lengths and custom terminations are
things that we do all the time.
If you think that you might need custom
cables, the very first thing you should
do is to contact your XLO dealer and tell
him what your requirements are. All XLO
cables are made in a wide variety of lengths
and offer a wide variety of terminations
AS STANDARD, so it's possible that you don't
really need custom cables at all! If you
do need something really special, your dealer
will be able to tell you exactly what it
will cost and (after he talks with us) give
you a firm date when your it can be available.
Give him a call! We and all of our dealers
are all Audiophiles and Home theater fans,
too, and we really WANT to make sure that
you get exactly what you need, exactly when
you have to have it!
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Q18:
Which type of video cable is better?
A18: There
are four basic types of video cable:
o Composite
o S - video
o Component
o RGB
The composite video system is by far the
most common (and the cheapest) and uses
a single coaxial cable (1 single center
conductor plus 1 overall shield/ground)
to carry all of your TV's sound, sync, chrominance
(color) and luminance (brightness) information
as a single matrixed signal. Composite video
cables are almost always terminated with
an "F" connector at each end.
S-video separates the video signal into
its chrominance and luminance elements and
carries them separately in a four conductor
shielded cable terminated with 4 pin "Mini-Din"
connectors which, because of their ubiquitous
use in this application, have come to be
known as "S-video" connectors.
Component video separates the video signal
differently, dividing it into its three
primary color components, red, green and
blue and carrying the color and brightness
information for each single color in one
of three single coaxial cables which make
up the complete component video "set".
Each of these three cables is usually terminated
with a "BNC" connector.
The RGB system is named for the three primary
light colors (Red, Green, Blue) and RGB
cables may consist of either four or five
(five is the more common) single coaxial
cable elements. If four are used, each single
cable carries one of Red, Green, Blue and
Sync. Five element cables add another cable
for Control functions. RGB cables are almost
always terminated with BNC connectors
As to which is better, the first thing
to determine is WHAT KIND OF CABLES ARE
YOUR COMPONENTS EQUIPPED TO TAKE? Whether
one is better than another makes no difference
if your equipment isn't set up to use it!
REMEMBER, ALSO, THAT BOTH COMPONENTS TO
BE HOOKED-UP WITH A PARTICULAR CABLE MUST
BE SET UP FOR THAT CABLE'S SPECIFIC OPERATING
SYSTEM. You CAN'T run from a (for example)
composite video output to an S-video input.
IT JUST WON'T WORK!
Even if you have all four systems available
to you on all of your equipment, it's still
not easy to determine which will be best
for your particular system under your particular
circumstances. Generally, ALL OTHER THINGS
BEING EQUAL, RGB will be the same as or
slightly better than Component Video, which
will be slightly better than S-video, which
will usually be a little better than Composite
Video. NONE OF THESE THINGS ARE CERTAIN,
HOWEVER. For long runs, Composite video
may actually be better than S-video, and
because of brand-to-brand and model-to-model
differences, the particular execution or
impedance match characteristics of any one
particular system on any one particular
component may be better or worse than any
of the other systems on that same component.
Our best suggestion is to either ask your
dealer about which type of cables will work
best with the equipment you have or intend
to buy, or try all of the systems available
to you before you make your purchase decision.
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Q19: I've read
in the magazines that 75 Ohm characteristic
impedance matching is important in my system
and my cables. What does that mean? What
IS characteristic impedance? How does it
affect my System? Is it really all that
crucial?
A19:
Video and coaxial digital signals and equipment
are specified by industry agreement to have
a characteristic impedance of 75 Ohms. Although
"Ohms" is the quantifying unit
for resistance, resistance isn't what is
being referred to in this case. Because
video and digital signals are always either
very high frequency AC or very rapidly occurring
digital pulses, they are affected not only
by resistance but also by capacitive and
inductive reactance. The combination product
of all three of these factors is called
"impedance", and impedance is
to AC and pulsed signals essentially what
simple resistance is to a DC current. The
"characteristic" impedance of
a circuit, a cable or a connector refers
to its characteristics when used as a transmission
line for high frequency or pulsed signals
and the most important thing about characteristic
impedance is not its specific value, but
whether the characteristic impedances of
all the elements to be used together (components,
cables, connectors) match.
Matching characteristic impedances in low
impedance circuits is always a good idea,
and the Hi-Fi and Home Theater magazines
are right when they say that a 75 Ohm source
and a 75 Ohm load should always be matched
to a 75 Ohm cable terminated with 75 Ohm
connectors. The problem is that even components,
connectors or cables that fall within the
normal range of variance allowed by their
specifications can still be 20% apart from
each other , and XLO has actually measured
input and output impedances on High End
components that were claimed to be "75
Ohm" but were really as low as 3 Ohms
or as high as 200.
The point of all this is that, regardless
of what your equipment's claimed characteristic
impedance may be, it may still be impossible
to match it correctly. Does this matter?
Maybe. It all depends on the frequency of
the signal that you want to pass and the
length of the cable that you want to pass
it through.
The reason for matching characteristic
impedances is that in a perfectly matched
transmission line, where all of the characteristic
impedances of all of the components, cables
and connectors is identical, all of the
signal energy that is put in at one end
of the line will be passed through and come
out at the other. In an IMPERFECTLY matched
transmission line, though, some of the signal
energy will not be passed through, but will
hit a point of mismatch and be reflected
(bounced) back to its source.
It's this reflected energy that creates
problems. Heading back down the cable like
a driver going the wrong way on a one way
street, the reflected signal energy "heterodynes"
(adds algebraically to form a new signal)
with the energy coming in the opposite direction
and produces -- just as one example - the
black bars or diamond shapes that appear
in the picture of a video system using mismatched
components or a too-long S-video cable.
Heterodyning artifacts are "noise",
in that they add something to the signal,
and they can be a serious problem in a video
or digital transmission system. Here's how
they come about:
All reflected energy can be described by
its frequency of reflection and by its relative
amplitude, as compared to signal level.
The frequency of reflection in a cable is
easily calculated by simply dividing the
length of the cable in meters into 300 million,
the speed of light expressed in meters per
second. Doing this, it's easy to see that
the frequency of reflection in a one meter
cable will be 300 megahertz (300,000,000
meters ) 1 = 300,000,000); that the frequency
of reflection in a 2 meter cable will be
150 megahertz (300,000,000 ) 2 = 150,000,000),
and so on, the longer the cable, the lower
the frequency of reflection.
As reflected energy passes back along the
line at its frequency of reflection, that
frequency adds to or subtracts from the
incoming energy to create a new "beat"
frequency (a heterodyne) at a frequency
which is the average of the frequency of
reflection and the frequency of the incoming
signal.
If the frequency of the incoming signal
is 5 megahertz and the frequency of reflection
is 300 megahertz, the heterodyne frequency
will be 152.5 megahertz:
5 megahertz
+300 megahertz
=305 megahertz
305 megahertz ) 2 [to get an average]
= 152.5 megahertz [1st heterodyne]
If the reflected energy represents 25%
of the signal energy, its amplitude will
be 6dB below signal level and the heterodyne
frequency will be 6dB below that, or a total
of 12 dB below signal level.
The heterodyne adds noise to the signal,
but it's far above the frequency of the
signal information and, even it's only 12
dB below signal level, it will probably
be of little consequence. That's not the
end of it, though:
the new (1st) heterodyne frequency, 152.5
megahertz, will also beat against the incoming
signal and will produce a second (2nd) heterodyne
at 78.75 megahertz, 18dB below signal level:
152.5 MHz [1st heterodyne] + 5 MHz [video
signal] = 157.5 MHz
157.5 MHz ) 2 = 78.75 MHz [2nd heterodyne]
Similarly, the 2nd heterodyne will beat
against the incoming signal to produce a
3rd heterodyne at (approx.) 42 mHz, and
so on, until (you can calculate this for
yourself if you want to) finally an 8th
heterodyne is formed at very close to the
video signal frequency, some 54dB below
signal level.
Will this matter? We don't know. We doubt
it, but it depends on how good your equipment
is; how good your eyesight is; and how picky
you are.
Remember, though, that that calculation
was done using the 300 megahertz frequency
of reflection of a 1 meter cable. If the
cable were TEN meters long (with a frequency
of reflection of only 30 megahertz) and
everything else was held the same, it would
only take a 4th heterodyne to get right
smack into the frequency range of the incoming
signal and that heterodyne, at only 30 dB
below signal level would DEFINITELY make
a difference.
So what does this all mean? First of all,
TRY TO KEEP YOUR DIGITAL AND VIDEO CABLES
AS SHORT AS POSSIBLE. Second, ALWAYS BUY
GOOD QUALITY PRODUCTS FROM REPUTABLE MANUFACTURERS.
Third, NO MATTER WHAT YOU DO, THERE'S ALWAYS
THE POSSIBILITY THAT YOU'LL STILL HAVE IMPEDANCE
MISMATCHES TO ONE DEGREE OR ANOTHER. Fourth,
DON'T WORRY ABOUT IT. SOME MISMATCHING IS
ALLOWED FOR IN THE SPECIFICATIONS FOR ALL
EQUIPMENT, AND - AS LONG AS YOU KEEP YOUR
CABLES AS SHORT AS POSSIBLE - A CONSIDERABLE
AMOUNT OF MISMATCHING CAN BE TOLERATED WITHOUT
ANY VISIBLE PROBLEMS AT ALL.
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