If wire is wire...

[Bavarian3 10+ year member]

wow someone bought it what the hell

 

[n2audio 5,000+ posts]

Originally posted by jlaine Wrong...

 

Not even in the general ballpark...

Wow - don't know that I've ever disagreed with one of your posts - this is a first.

Shields are useful against frequencies much higher than that which are present in the car audio environment. In a car shielded cables are more likely to pick up the lower frequency noises that are present than they are to reject them.

UTP's are the way to go.

 

[jlaine 10+ year member]

Originally posted by n2audio Wow - don't know that I've ever disagreed with one of your posts - this is a first.

 

Shields are useful against frequencies much higher than that which are present in the car audio environment. In a car shielded cables are more likely to pick up the lower frequency noises that are present than they are to reject them.

 

UTP's are the way to go.

Wrong again.

Please reference factual and documented information proving your theory before we continue this argument.

I'll quote an old conversation going into detail why utp is pointless.

In single ended systems, shielding is what matters; in balanced systems, twisting matters.
PREAMBLE - the following is based upon my understanding of E/M theory, and the result of a good 10 years in scientific research applications using cable...

Twisted pair operates on the premise that induced noise should be equally induced - in amplitude and phase - on both lines. The goal isn't to avoid induced noise; the goal is to make sure induced noise is equally coupled to both leads.

Take a pair of wires: A+ and A-. Now, put a signal down the wires; let's take the signal (X) and break it into two parts,B and C such that (B - C = X). Now, put x+ on A+, and x- on A-. In effect, X = A+ - A-.

Now, couple in noise, N, to both leads. What do you get at the end? Well, on A+ we have B + N. On A- we have C + N. Now do the subtraction to get back to X:

X = A+ - A- = (B + N) - (C + N) = B + N - C - N = B - C.

Note that the noise cancels out! That is the result of a balanced system, where the signal is the DIFFERENCE between what is on the two conductors. And this is why pro-sound applications use balanced conductors (XLR, which has both A+ and A- conductors, plus a shield/ground reference). We don't care if noise gets on to the line; we want it to get on both lines equally so that when we take the difference the noise gets cancelled out.

Now, let's consider an unbalanced system, like you have with RCAs. You have the same wire, A+ and A-. In this case, the signal X is placed on A+. Ground is on A-. All should be OK, right?

Wrong. The problem is that ground IS ground - it can sink lots of current (relatively speaking). As such, inducing noise on to the ground lead does NOT result in the same amount of induced noise as on the signal lead. You can think of it as the signal on A+ getting N noise, and the ground getting N/2 (or less) noise. Now the difference between signal and ground is NOT the same - the noise is not equally coupled. The result? Noise in the line.

Shielding acts to stop radiated fields. In particular, we're concerned with electric fields, as you get from most car noise sources. The noise is coupled into the shield, and - provided the shielding is sufficient - the noise field is blocked from the conductor. It can't get to the conductor at all. Then you can derive a filtered ground at the receiving end of the signal, and the coupled noise on the shield isn't a problem - you don't even worry about the signal/reference on the shield.

So, in terms of balanced systems, shielding is redundant; we don't care if it's there or not, since we want it to equally couple to both conductors.

In terms of unbalanced systems, shielding is the ONLY way we can eliminate noise. We have to keep the noise from getting on the signal at all, since we can't subtract it back out (we're not balanced).

Now, as far as cables go... I worked in the SONAR research field for a a good 6 years. In that time, I designed some VERY high-end (still state-of-the-art) gear, with full 22 bit dynamic range (132 dB S/N+D levels) capability. Beyond what extreme-high-end audio can do, even.

Anyway, we used to instrument up the fronts of dams, to monitor fish bypasses. Lots of concern of salmon getting sucked through the turbines on power generation dams, rather than using the fish bypasses. So lots of money spent on using SONAR to track the fish, determine how/where they are moving, and use that information to build more effective bypasses.

Now, a typical SONAR element will return signals on the order of 10-15 microvolts from a typical 1 year old salmon, at a range of 5 meters. In other words, we get VERY low signals from the elements. And we have to measure and quantify that signal, to make the determination of how effective the current bypass is.

Problem is, we were installing on dams - power generation dams. As such, we often ran over 1000' (yes, one thousand) feet of cable along the top of a dam. You know, where you have 500 kV (half a million volts) floating around. Not like the easy 40 kV you have in a distributor!

So, how did we make our measurements so noise-free? Balanced systems and good cable. We used LOTS of Belden 8412 - around $0.60 a foot, in 100 foot quantities (around $0.11 a foot when buying a mile). Twisted shielded pair. The reason for twisted was pretty obvious - noise rejection. But the shielding was just as critical! If it wasn't there, the noise induced on the signal wires could be as high as 400-500V, and blow up the preamp inputs! With the shielding, the induced noise was in the range of a mV or two; easy to handle, and since it was equally coupled on both lines balancing cancelled it out.

So, from that point on I use Belden 8412 for line level signals. You can use it balanced or unbalanced, it's very tough (rubber jacket over the conductors, and over the shield), cotton filler (non-conductive), good braided shield, etc. And easy to pull - not too fat at all. Overall, great cable to use, easy to work with, and relatively low cost. Looks nice, too...

Dan Wiggins

Adire Audio

Now I'd almost buy your idea, except for the reality you are attempting to state that shielding will induct noise, when it really can't, the potential isn't there.

Problem is, I could never even realistically reproduce such an instance like you are purporting even if I wanted to.

Your other "idea" about low frequency is also flawed and I'll go into detail as to why.

Shielding is used in pro sound to eliminate (for the most part) 60 cycle noise induced by ballasts and other radiant sources from power lines, lights, etc. That is in no way high frequency - and guess what?

Yup... It works.

Try running UTP across that region (in an unbalanced line) once and see what you get other than a LOT of induced noise.

 

[eengrms 10+ year member]

Originally posted by jlaine Wrong again.

 

Please reference factual and documented information proving your theory before we continue this argument.

 

I'll quote an old conversation going into detail why utp is pointless.

 

 

 

Now I'd almost buy your idea, except for the reality you are attempting to state that shielding will induct noise, when it really can't, the potential isn't there.

 

Problem is, I could never even realistically reproduce such an instance like you are purporting even if I wanted to.

 

Your other "idea" about low frequency is also flawed and I'll go into detail as to why.

 

Shielding is used in pro sound to eliminate (for the most part) 60 cycle noise induced by ballasts and other radiant sources from power lines, lights, etc. That is in no way high frequency - and guess what?

 

Yup... It works.

 

Try running UTP across that region (in an unbalanced line) once and see what you get other than a LOT of induced noise.

I haven't really been following this argument, but I do have a question.

Since when do you have ballasts (assuming you mean lamp ballasts) and radiant sources in 'pro sound'?

I work in a telecom field, somewhat, and shielded wiring is the standard. So I agree with you, but that statement made me wonder if you were just pulling this stuff out of your ***.

 

[jlaine 10+ year member]

Originally posted by eengrms I haven't really been following this argument, but I do have a question.

 

Since when do you have ballasts (assuming you mean lamp ballasts) and radiant sources in 'pro sound'?

 

I work in a telecom field, somewhat, and shielded wiring is the standard. So I agree with you, but that statement made me wonder if you were just pulling this stuff out of your ***.

Quaint...

When don't you have radiant sources in pro sound?

Have you ever gone to a party hosted by a DJ?

See any strobes? Fluroescent Lighting? HID lighting? Neon?

Any signal wires run next to 120V sources? 220?

I find it an enjoyable pasttime to pull things out of my ***... Don't you?

 

[ramos 5,000+ posts]

Originally posted by jlaine  

I find it an enjoyable pasttime to pull things out of my ***... Don't you?

I really don't know . I have never tried to pull anything out of your *** //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif j/k //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[n2audio 5,000+ posts]

My "E/M theory" consisted of an engineering physics class about 8 years ago, I managed a B, but I recall little, if anything about it.

However, there are a few members at carsound that I consider 95% of what they say to be pure scientific fact - so I'll stick to UTP's.

 

[jlaine 10+ year member]

Originally posted by n2audio  

However, there are a few members at carsound that I consider 95% of what they say to be pure scientific fact - so I'll stick to UTP's.

That's fine, you can blindly follow...

I'll return to making sure what I say is backed up with verifiable proof.

Remember, just because the change isn't audible, doesn't mean it isn't there.

One is more physically sound, whether or not you choose to believe it based on someone's name doesn't concern me.

I've run lamp cord in my car with no noise resultant - that's because the noise level just isn't there in most cases. But, that does not lend any to your theory that UTP is better.

 

[ss3079 5,000+ posts]

Originally posted by jlaine I find it an enjoyable pasttime to pull things out of my ***... Don't you?

Not if Derek's been up there.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

- Steve

 

[jlaine 10+ year member]

Originally posted by ss3079 Not if Derek's been up there.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

- Steve

Awww...

No sloppy seconds for you?

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[ss3079 5,000+ posts]

Originally posted by jlaine Awww...

No sloppy seconds for you?

 

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Heck no, I'll leave it to the boys at SIN this time.

Oh and hey, who was the guy that was supposed to send me the chicken video's?//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

- Steve

 

[eengrms 10+ year member]

Originally posted by jlaine Quaint...

 

When don't you have radiant sources in pro sound?

 

Have you ever gone to a party hosted by a DJ?

 

See any strobes? Fluroescent Lighting? HID lighting? Neon?

 

Any signal wires run next to 120V sources? 220?

 

I find it an enjoyable pasttime to pull things out of my ***... Don't you?

Ohhh... 'pro sound'... I was under the assumption we were talking about something relavent like car audio, since that was what n2audio was talking about... my mistake.

 

[jlaine 10+ year member]

Originally posted by eengrms Ohhh... 'pro sound'... I was under the assumption we were talking about something relavent like car audio, since that was what n2audio was talking about... my mistake.

Quite relevant... I guess I need to expand on the basics for you since you are missing it.

Ever seen a car with a neon tube somewhere near an amp rack for decoration?

How about strobes?

Linear actuators?

I have... If you haven't, then get outside more often.

Your only mistake so far is thinking the two don't have quite relevant similarities.

 

[n2audio 5,000+ posts]

here's what they think.

http://www.carsound.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic&f=1&t=021545#000000

I'm using some $10 foil shielded (when I bought them I thought they were mylar) BOSS cables and have no audible noise - obviously, I have no need to upgrade.

Can we just agree that the best cables to use are the ones that work best for you??

 

[eengrms 10+ year member]

Originally posted by jlaine Quite relevant... I guess I need to expand on the basics for you since you are missing it.

 

Ever seen a car with a neon tube somewhere near an amp rack for decoration?

 

How about strobes?

 

Linear actuators?

 

I have... If you haven't, then get outside more often.

 

Your only mistake so far is thinking the two don't have quite relevant similarities.

That's quite a condescending tone.

So let me get you straight... we all need to use shielded wire in the event we put strobes or neons in our car?

I guess you are smarter than me because you treat this one specific example as if it were an everyday occurance, rather than the anomaly that it is.

Why did I get in the middle of this? I guess I didn't realize you're the type of guy who isn't going to change his mind, just get more mad the longer we talk about it and use phrases like "I guess I need to expand on the basics for you" and "get outside more often" to make yourself feel better.

Good luck with all that.