ok, as I am going thru the process of building my system in my car, I have
ineviteably came to the point of chosing some interconnects for it. my
question is... which rejects noise better, twisted pair, or standard sheiled
sheilded. or, more to the point.. do I really need to pay 60 bucks for
interconnects (i.e. 1 12 ft Stinger Expert series Interconnect, Street wires
Zero noise series 12 ft, ect)
or are the 6.99 Radio Shack offerings just as good as far as sq/noise
rejection goes

In article D7KSa.97099$GL4.26973@rwcrnsc53,
"Lex" wrote:

ok, as I am going thru the process of building my system in my car, I have
ineviteably came to the point of chosing some interconnects for it. my
question is... which rejects noise better, twisted pair, or standard sheiled
sheilded. or, more to the point.. do I really need to pay 60 bucks for
interconnects (i.e. 1 12 ft Stinger Expert series Interconnect, Street wires
Zero noise series 12 ft, ect)
or are the 6.99 Radio Shack offerings just as good as far as sq/noise
rejection goes



The cheapest cables at Radio Shack and most hardware stores are bad.
They're thin and you can sometimes feel loose strands of wire crunch
around when you roll the cable between your fingers.

Spend another $3 for one grade higher and you're good. Inexpensive
cables shield just fine. No cable will fix a ground loop. Forget about
$60 cables because there's nothing they can do better.

The only effects that spending $60 on interconnects may have (besides less $
in your wallet) are psychological effects. Since you spent $60 you might
THINK your music sounds better, but in reality, you won't hear a difference.

So.. if you need that psychological reinforcment, then spend $60, otherwise
save yourself a wad of cash and buy generics or make your own.


"Lex" wrote in message
news7KSa.97099$GL4.26973@rwcrnsc53...
ok, as I am going thru the process of building my system in my car, I have
ineviteably came to the point of chosing some interconnects for it. my
question is... which rejects noise better, twisted pair, or standard
sheiled
sheilded. or, more to the point.. do I really need to pay 60 bucks for
interconnects (i.e. 1 12 ft Stinger Expert series Interconnect, Street
wires
Zero noise series 12 ft, ect)
or are the 6.99 Radio Shack offerings just as good as far as sq/noise
rejection goes




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"Lex" wrote in message
news7KSa.97099$GL4.26973@rwcrnsc53...
ok, as I am going thru the process of building my system in my car, I have
ineviteably came to the point of chosing some interconnects for it. my
question is... which rejects noise better, twisted pair, or standard
sheiled
sheilded. or, more to the point.. do I really need to pay 60 bucks for
interconnects (i.e. 1 12 ft Stinger Expert series Interconnect, Street
wires
Zero noise series 12 ft, ect)
or are the 6.99 Radio Shack offerings just as good as far as sq/noise
rejection goes


I prefer the nicer cables just because there more rugged, thicker, and look
nicer for an install. They seem to stay connected much better than the super
cheap ones which may just come loose in a moving enviroment like a car. Just
avoid the 'twisted pair' rca cables. there a complete waist and dont provide
any shielding at all. even the cheap cables shield better than these pieces
of crap.

Paul Vina wrote:

Just to play devil's advocate, twisted pair cables reject noise better
because the accept less noise than a standard rca because the conductors are
closer together than in a regular rca

No, that's not right. They reject noise because the wires are at roughly
90 degree angles to each other. Any voltage inducted onto one conductor
will be out of phase with a voltage inducted on the adjacent section of
conductor.


--
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teamROCS #007 / Technical Director / Founding Member *res derelicta*
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No, that's not right. They reject noise because the wires are at roughly
90 degree angles to each other. Any voltage inducted onto one conductor
will be out of phase with a voltage inducted on the adjacent section of
conductor.


But the noise is still there just quieter. If it was out of phase it would
be completely gone and there would be no need to use digital or balanced
cables. And the conductors aren't at 90 degree angles with one another
either. Besides, they don't reject noise, they just pick up less of it
compared to standard RCA's.

Paul Vina

In article ,
The Lizard wrote:

Paul Vina wrote:

Just to play devil's advocate, twisted pair cables reject noise better
because the accept less noise than a standard rca because the conductors are
closer together than in a regular rca

No, that's not right. They reject noise because the wires are at roughly
90 degree angles to each other. Any voltage inducted onto one conductor
will be out of phase with a voltage inducted on the adjacent section of
conductor.

For fields far away.

Twisted pair can work better when there are no nearby noise sources. It
cancels distant electromagnetic fields and it acts somewhat as common
mode rejection transformer (can reduce some ground loop noise). It
doesn't reject nearby sources well because the signal applied to each
wire isn't well balanced.

I don't think I would use it in a car because noise sources could come
very close to the wire. It would be better for house wiring where the
distance from noise sources can be easily controlled during installation.

"The Lizard" wrote in message
...
Lex wrote:
ok, as I am going thru the process of building my system in my car, I
have
ineviteably came to the point of chosing some interconnects for it. my
question is... which rejects noise better, twisted pair, or standard
sheiled
sheilded. or, more to the point.. do I really need to pay 60 bucks for
interconnects (i.e. 1 12 ft Stinger Expert series Interconnect, Street
wires
Zero noise series 12 ft, ect)
or are the 6.99 Radio Shack offerings just as good as far as sq/noise
rejection goes


That depends if you have a noise problem or not. I've done tons of
installs with the el-cheapo rat-shack RCA's without a problem.

When I do get noise, I use twisted pair. It works for high speed
computer networks, and it works for car audio.

Totally different animals. "twisted pairs" in networks uses pairs of cables
for each signal. TX+ TX- are on a pair, RX+ RX- are on another pair. the TX
for example sends the same signal twice only in opposite polarity(balanced).
So, if I have an original signal of 1,0,1 on the + and -1,0,-1 on the minus
then a differental amp would output 2,0,2

now if I induce +37v on noise on each line; I get 38,37,38 on the + and
36,37,36 on the minus. a differential amp still outputs 2,0,2


In an rca "twisted pair" cable. one cable is signal the other is ground. the
signal cable is getting the noise just like the ground but the recieving
amps own chassis ground will still be the reference and will hardly be
affected by the noise on the cable's ground. then your left with a noisy
signal referenced to chassis ground. bad.

A simple (elcheapo) rca cable with signal on the center conductor insulated
by a conductive shielding attenuates noise much better than nothing.(which
rca 'twisted pair gives)

http://www.westbay.ndirect.co.uk/ShieldingTools.htm (not an audio site)
this site has some tools to calculate the effectiveness of different
shielding types. note that the twisted pair refenences on the page are
refering to true twisted pairs and not the miss named for marketing; rca
twisted pair cables.


Sheilding really is anywhere from highly unecessary to
counterproductive. More importantly, it's needlessly expensive.

I'd recommend going with simple twisted pair right off the bat. They're
more expensive than the elcheapo, but it's worth saving the labor if you
do have a noise issue. It'll also give you peace of mind.

Do NOT buy ZN, Expert, or any of that other ****. It's all VooDoo
technology. Esoteric Streetwires justifies it's cost with higher
precision machining of the RCA's, and better materiels that are more
robust for car environments. But honestly, if you buy some $20/ft RCA's
that feature "discrete paths" for "time aligned audio signals", I'll
kick your ass.


agreed!!

I found some speaker cables that claimed "time aligned "
15' and $400 bucks!



--
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teamROCS #007 / Technical Director / Founding Member *res derelicta*
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Save Farscape http://www.watchfarscape.com

You don't think they're at ~90 degree angles? Twist a wire...holy ****,
what do you make of that?

I have, many times and they're lucky if they're a 45 degree angle. If it
was 90 degrees or close the cables would be a lot thicker than they are.



...and this is different from rejection how?


I would call rejection something that happens actively. The cables aren't
*doing* anything to keep the noise away, they're just not picking up as much
of it. That's like saying a small bucket rejects water because it will hold
less of it.



Don't answer...please...

Why?

Paul Vina

They're roughly 90 degrees, which means they're only roughly out of phase.

Very roughly out of phase, Yes they are out of phase to some degree, but in my
mind I consider "out of phase" to mean 180 degrees apart.

Besides, they don't reject noise, they just pick up less of it
compared to standard RCA's.

...and this is different from rejection how?

I would agree with Paul, rejection to me implies that it actually did
something, but in reality it just did less work.
But noise is very rarely an issue with RCAs anyway so I cannot see any
advantage to using twisted stuff.

Les

Paul Vina wrote:

I have, many times and they're lucky if they're a 45 degree angle. If it
was 90 degrees or close the cables would be a lot thicker than they are.

Paul, do the math. Each wire is at a ~45 degree angle to center. Their
total offset from each other is ~90 degrees.

Don't answer...please...


Why?

Cause it could get ugly. The issue everyone will miss entirely is that
twisted pair offers better sheilding than plain wire, but that it's not
that big of a deal. Most causes of noise have little to do with radiated
noise, and more to do with fault equipment and most commonly, poor
installation.

--
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teamROCS #007 / Technical Director / Founding Member *res derelicta*
http://www.teamrocs.com/
Save Farscape http://www.watchfarscape.com

Soundfreak03 wrote:
They're roughly 90 degrees, which means they're only roughly out of phase.


Very roughly out of phase, Yes they are out of phase to some degree, but in my
mind I consider "out of phase" to mean 180 degrees apart.


180 degree is out of phase. 1 degree is out of phase. What's your point?
If you could put the wire 180 degree out of phase, you'd have near
perfect noise rejection. But any phase difference helps suppress induced
noise.



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Paul, do the math. Each wire is at a ~45 degree angle to center. Their
total offset from each other is ~90 degrees.


I meant 45 degrees total. I'm looking at one right now and there is no way
they cross at a 90 degree angle or or even have a 90 degree total offset.




Cause it could get ugly. The issue everyone will miss entirely is that
twisted pair offers better sheilding than plain wire, but that it's not
that big of a deal. Most causes of noise have little to do with radiated
noise, and more to do with fault equipment and most commonly, poor
installation.



I agree with this as well. This discussion would be be best left alone as
long as the benefits are noted.

Paul Vina

180 degree is out of phase. 1 degree is out of phase. What's your point?
If you could put the wire 180 degree out of phase, you'd have near
perfect noise rejection. But any phase difference helps suppress induced
noise.

yes but when someone refers to "out of phase" most people assume 180. Thats the
point. If thier is a phase reverse switch on some component and it is not
labeled then what degree do you assume? 180.
And how often is induced noise a problem in car audio? Not alot in my
experience. Were talking less than a 20ft run anyway. And were not talking
about massive power sources, So I still think that twisted cables are not any
better.

Les

Soundfreak03 wrote:

yes but when someone refers to "out of phase" most people assume 180.

Never ASSume anything.

Thats the
point. If thier is a phase reverse switch on some component and it is not
labeled then what degree do you assume? 180.

I never assume anything. However, experience tells me that it'll be 90
degrees, not 180. What's the point in changing your bass 180 degrees?
It'll destroy your sound by cancelling out at the frequencies where your
subs overlap with your highs.

Some phase switches don't even have a specific phase. I had a crossover
once upon a time that had "vPhase". The degree of phase was shifted
according to the crossover point the crossover is set at.

And how often is induced noise a problem in car audio? Not alot in my
experience. Were talking less than a 20ft run anyway. And were not talking
about massive power sources, So I still think that twisted cables are not any
better.

I mentioned this in another post. Most noise problems are because of
damaged equipment, or more commonly, poor installation.

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In article ,
The Lizard wrote:

Paul Vina wrote:

I have, many times and they're lucky if they're a 45 degree angle. If it
was 90 degrees or close the cables would be a lot thicker than they are.

Paul, do the math. Each wire is at a ~45 degree angle to center. Their
total offset from each other is ~90 degrees.

Don't answer...please...


Why?

Cause it could get ugly. The issue everyone will miss entirely is that
twisted pair offers better sheilding than plain wire, but that it's not
that big of a deal. Most causes of noise have little to do with radiated
noise, and more to do with fault equipment and most commonly, poor
installation.

And the world is flat.

Twisted pair is not superior in signal quality to shielded cable. It's
just _much_ cheaper.

Forget about the degrees of separation; there is none. You're smoking
crack again. It's a matter of inductive pickup. From a distance, the
magnetic fields of the wires are in perfect balance so there's no
differential radiation or pickup between the wires. The wires are
twisted so that, to a distant object, one wire is not significantly
closer than another. Twisted pair wires pick up and radiate plenty of
electromagnetic fields at close proximity. Use twisted pair wires as
microphone cable and you'll see its limitations very clearly.

Twisted pair wires will also not eliminate alternator whine caused by a
ground fault. There isn't enough inductance to eliminate common mode
currents at such low frequencies. If you spun 100 feet of twisted pair
around a magnetic core, then yes, it would eliminate some whine.

yes but when someone refers to "out of phase" most people assume 180.

Never ASSume anything.


You have to assume certain things, come on even you do that and know that. Get
off your high and mighty horse just so you can be right.

Thats the
point. If thier is a phase reverse switch on some component and it is not
labeled then what degree do you assume? 180.

I never assume anything. However, experience tells me that it'll be 90
degrees, not 180. What's the point
in changing your bass 180 degrees?

Of course you never assume anything. You always have the time and energy to get
out the equipment and measure if its not labeled. Well I am sorry but I dont so
you have to make certain assumptions based on what is typical of something.
If you are getting cancelation then a phase swap of 180degrees could definantly
help that, hey so could 90 but I have definantly seen more 180s. But I dont
only deal with car audio, in fact my main profession is designing and operating
Pro Audio systems. And I will tell you that if it says phase reverse or
whatever then it most likely means 180.

It'll destroy your sound by cancelling out at the frequencies where your
subs overlap with your highs.


Unless they already are then it is the best thing you could do.

What's the point in changing your bass 180 degrees?
It'll destroy your sound by cancelling out at the frequencies where your
subs overlap with your highs.

sigh

Kevin McMurtrie wrote:
And the world is flat.

Twisted pair is not superior in signal quality to shielded cable. It's
just _much_ cheaper.

Nobody said it was better in signal quality. It's just better to
rejecting noise than standard two conductor RCA's.

snip blah blah blah **** that totally contradicts physics

Twisted pair wires will also not eliminate alternator whine caused by a
ground fault.

Who said it would? Ground fault (or more properly for this discussion,
ground loops) have nothing to do with em fields.

There isn't enough inductance to eliminate common mode
currents at such low frequencies. If you spun 100 feet of twisted pair
around a magnetic core, then yes, it would eliminate some whine.

You could eliminate some high frequencies to. You could introduce whine.
They use coils in radio many radio receivers. You ever put a crossover
near an ECM?

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Soundfreak03 wrote:

Of course you never assume anything. You always have the time and energy to get
out the equipment and measure if its not labeled. Well I am sorry but I dont so
you have to make certain assumptions based on what is typical of something.

You don't need test equipment for COMMON SENSE things like this. You
make assumptions because you don't have the knowledge or experience to
know better. But that doesn't make it right. Assumptions get you killed
("I assumed there was no train, since I didn't see any flashing lights!").

If you are getting cancelation then a phase swap of 180degrees could definantly
help that, hey so could 90 but I have definantly seen more 180s. But I dont
only deal with car audio, in fact my main profession is designing and operating
Pro Audio systems. And I will tell you that if it says phase reverse or
whatever then it most likely means 180.

Who said "phase reverse"? You're pulling **** our of your ass now. We've
been talking about phase shifts.


Unless they already are then it is the best thing you could do.

The best thing you can do is set everything up properly.

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In article ,
The Lizard wrote:

Kevin McMurtrie wrote:
And the world is flat.

Twisted pair is not superior in signal quality to shielded cable. It's
just _much_ cheaper.

Nobody said it was better in signal quality. It's just better to
rejecting noise than standard two conductor RCA's.

snip blah blah blah **** that totally contradicts physics

Twisted pair wires will also not eliminate alternator whine caused by a
ground fault.

Who said it would? Ground fault (or more properly for this discussion,
ground loops) have nothing to do with em fields.

There isn't enough inductance to eliminate common mode
currents at such low frequencies. If you spun 100 feet of twisted pair
around a magnetic core, then yes, it would eliminate some whine.

You could eliminate some high frequencies to. You could introduce whine.
They use coils in radio many radio receivers. You ever put a crossover
near an ECM?

No, it would not eliminate any high frequencies. You really need to
take a basic electronics course. You're like a 3 year old kid
explaining the universe on some quick observations.

You don't need test equipment for COMMON SENSE things like this.

Yes and its common sense that tells you when talking about changing the
phase
most people are referring to a 180degree shift. Maybe you dont but IME
thats
how MOST experienced installers think.

Remember what he was addressing initially. The orientation of wires with
respect to one another in terms of a noise issue. What good would 180
degrees be? It's essentially the same as 0 in this context.

Who said "phase reverse"? You're pulling **** our of your ass now. We've
been talking about phase shifts.


"phase reverse or whatever" I dont keep up with your exact wording so
thats why
I put whatever so that you knew I was referring to whatever the hell you
want
to call it. Phase shifts, phase reverse, if its not specified then I would
think 180 unless I had reason to think otherwise. What do you think it is
most
of the time?

"Phase shifts" usually do not refer to 180 degree reversals. At least no
more than any other phase angle. In this field, you most commonly see the
term applied to filtering.

Remember what he was addressing initially. The orientation of wires with
respect to one another in terms of a noise issue. What good would 180
degrees be? It's essentially the same as 0 in this context.


You are correct Mark. But now weve got to the point where we are arguing over
what you would assume when some just talks about changing phase. So thats the
deal now

"Phase shifts" usually do not refer to 180 degree reversals. At least no
more than any other phase angle. In this field, you most commonly see the
term applied to filtering.


Well I guess I am relating to much other audio gack to it. But myself and
other audio guys would assume a phase shift of 180degrees if no other info was
given. Phase is often denoted with the symbol PHI and most times no degree
given. But 99% of the time it means 180.
So the point I am making is just that what I have said above. That what the
argument seems to be about.

Les

I rarely see this on RAC, but this is SO TRUE!
I couldnt have said it better myself....

Eddie Runner

Kevin McMurtrie wrote:

Twisted pair is not superior in signal quality to shielded cable. It's
just _much_ cheaper.

The Lizard wrote:

Yes, but the wires _are_ twisted to reject noise.

No Liz,
the wires are twisted together to induce noise equally IN BOTH and
that noise is cancelled in a balanced system...

the twists reject noise from one wire to another!! NOT outside noise!


Eddie

"The Lizard" wrote in message
...
scott johnson wrote:

Coils are also used in high-pass filters.

Yes, they are. Very good observation. But look at how they are used:
they shunt low frequncies, thereby increasing the slope of the high pass
crossover.

http://www.teamrocs.com/technical/pages/twoway.htm

Do you see how that coil is connected in parallel with the tweeter? The
coil has a lower resistance than the tweeter, so electicial current will
go through it instead of the tweeter. That is, of course, until the
frequency rises to the point where the coild has more resistance than
the tweeter. Electical currents at those frequencies will then go
through the tweeter.

A typical crossover which only uses one element has roughly a 6 db /
Octave filter slope. But adding the opposite element at a value that
provides the same crossover slope provides up to 12 db / octave of
filter slope.



Erm? yes, this is ultra-basic stuff.

scott johnson wrote:

Erm? yes, this is ultra-basic stuff.


Yes it is...so next time don't feel the need to explain it to me.



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