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Discussion Starter · #1 ·
I saw this question time and again in various forms with generally the same answer while searching. That answer is that you can use any as another.


What I want to know is what the physical differences are. As in, if I were to take each type and cut them in half what would I see.


I saw one claim that all of them have coaxial wire in them. This simply must be bogus there is no way that the white/red ones are like that since they are far too thin. Generally so is the yellow one. Alot of times they actually all three are the same thickness even though the yellow is supposed to be more substantial than that.


Then there's component which should be more than that and digital coax and subwoofer cable which all appear to be the same thing. I know they can be used as such, I just want to know the physical - not electrical measurements - difference.
 

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Component video is three yellow (composite) video cables tied together. No physical difference at all, except the color of the plugs so the connections are correct (red to red, green to green, blue to blue.) If you cut them open, they'll look the same. It's all just electrical pulses.


Digital coaxial is the same thing, too. Just repurposed and color coded so newbs can easily connect things up.


Monoprice markets its digital coaxial, subwoofer, and composite video cable as the exact same thing. They're rated at 75ohm. Analog audio doesn't have to have that ohm rating, but some companies make it that way anyway.

http://www.monoprice.com/products/su...02&cp_id=10236


Subwoofers can use one red/white analog audio, although using a composite/component/digital coax cable won't hurt anything as well.
 

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Coaxial cable--concentric shield around a central conductor separated by a dielectric with specific electrical properties and geometry to maintain a specific characteristic impedance. Necessary for things that function as transmission lines, like RF, digital audio, etc. but not necessary if the length of the cable is less than a significant fraction of the wavelength of the signal.


Shielded cable--shield (that doesn't necessarily stay concentric) around an insulated central conductor, distance between shield and center conductor can vary. Not designed to maintain a specific characteristic impedance. Fine for audio because unless they are very long, audio cables do not function as transmission lines.


Shielded twisted pair--shield around a twisted pair of insulated wires. Sometimes used for unbalanced connections (RCA), more often for balanced connections.


Twisted pair--no shield. Used to be common back in the days of tubes.
 

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So to sum it up. Technically all RCA type cables are the same basic wire but some companies make little tweaks to them for better "performance", performance most people will never see or hear. Really cra... bad cables may have issues but only if there is a defect in them or if the cable has been compromised due to a very bad cut or a VERY powerful local source giving incredibly strong em/rf interference.


I like a thicker cable... It just looks cool and gives me a little piece of mind.
 

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Okay fine. But my point was that unless he is using very long runs for very precise things he will hear no difference.
 

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Kinda true for audio over an unbalanced connection, but not for video or digital audio.


For most analog video and digital video, except for very short runs, you need to use 75 ohm coaxial cable because the cable is acting like a transmission line and the sending and receiving equipment are designed to match up with the 75 ohm cable. If you don't part of the signal will be reflected at the receiving end, degrading the signal. For video, the effect can be subtle to pronounced. For digital, you won't notice anything until it gets bad enough to start affecting the values of the bits.


For analog audio, simple shielded cable works as well in almost cases, like those skinny things that come with some equipment because at practical lengths the cable does not function as a transmission line, and the equipment isn't designed as if it did anyway.


Can you use coax for audio? Sure, doesn't even have to be 75 ohm. Won't hurt anything unless it is a long run and the capacitance of the particular cable is high enough to roll off the high end. It is convenient to have just one type of cable. Down side is that the cables are not as flexible. Looks more impressive, but doesn't really do anything for you.
 

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Discussion Starter · #9 ·

Quote:
Originally Posted by m-heat /forum/post/19570092


Okay fine. But my point was that unless he is using very long runs for very precise things he will hear no difference.

Technically speaking that was the exact type of answer I wasn't looking for. I already know this and stated as much.


After all this

http://en.wikipedia.org/wiki/RG/6


states that RG/6 or current cable/antenna cables are used as digital coaxial cable (it doesn't say that it's the only kind used, however). Is it, or are there others?


1. After seeing my HD antenna's in, it makes me wonder why we opted for using the extra hassle of component instead of just one of these (or digital coax, but for video) because it's obviously capable of plenty.


2. So then its, in order of beefiness, the coax (which may or may not be RG/6) - including digital coaxial and subwoofer cable. Then the "regular" yellow stuff which definitely has less shielding in it - including composite video and component. Then there's the white/red which can be nearly anything and still end up with those ends in buyable wires. Correct me if I'm wrong.


3. I saw something about subwoofer cable having a separation of grounding to eliminate possible hum caused by differences of grounding voltage in the sub and the receiver. How important is this?


Thank you for all the to the point responses I've gotten so far, it was starting to bug me alot that all I could find on the topic was that anything with RCA connectors could be used interchangeably. Even though the connectors themselves were apparently originally used for phonographs, and just have been used for various things over the years. It also seems strange to me that all the current connectors (besides ones invented in the last 10 years, like HDMI and DisplayPort) are all basically 50 plus years old.
 

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The RG classification system is obsolete. Manufacturers continue to label things as RG6 type, RG59 type, etc. to narrow down the range when you are looking for a cable. There are many different types of coaxial cable, differing in characteristic impedance, size, shielding, etc. RG59, RG6, an RG11 are all classes of 75 ohm cables and differ primarily in size and attenuation of the signal. There are other 75 ohm coaxial cables that don't fit the RG scheme. A larger cable will typically have lower attenuation than a smaller cable, all other things being equal.


A thinner cable doesn't necessarily have less shielding. The bulk of coaxial cable comes from the plastic dielectric that separates the center conductor from the shield. RG6 is thicker than RG59 because it has a thicker dielectric. Simple shielded cable will be thinnest, all other things being equal, because there is not plastic dielectric between the the center conductor and the shield other than the insulation around the wire.


Some shielded twisted pair cables have the shield grounded at one end only. Whether this is advantageous or not will depend on your system. If you have real hum problems from induced 60 Hz from your power, it may be that nothing short of encasing the subwoofer cable in steel conduit will work.
 

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Discussion Starter · #11 ·
I'm just asking stuff because I wanted to know what stuff really is.


I just bought a refurb S5300 HTIB, so it's not like I'm having any actual problems with anything (subwoofer hum included, that was just the only real specific thing that was mentioned as an actual difference when I was searching.)


I'm planning to buy one of the $10 rosewill 1.4 HDMI (I already have one figure I might as well get another in case I end up with stuff that wants it) cables and I'll use the free 12-foot digital coax for the subwoofer. All other HDMI cables will just be the $3-4 1.3 version since I don't have anything that actually uses the new standard. (for now)
 

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Quote:
Originally Posted by False_Dmitry_II /forum/post/19570348


It also seems strange to me that all the current connectors (besides ones invented in the last 10 years, like HDMI and DisplayPort) are all basically 50 plus years old.

well, there's no compelling reason to change them just because they are 50 years old...
 

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Almost all the cheap stuff I've ever seen, including the throwaway cables that come with any AV equipment, is coax. It's usually very low quality tiny-gauge mystery coax churned out en-masse, but that's almost universally what I encounter.


Unless you're in pro audio using balanced connections (in which case you need twisted pair), high-quality coax is generally the way to go.
 

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Quote:
Originally Posted by ccotenj /forum/post/19572211


well, there's no compelling reason to change them just because they are 50 years old...

But it sure would have been nice if they had picked the right 50 year old connector for the video and digital audio, BNC. There is no RCA plug that matches the 75 ohm impedance used for the cable. The use of RCA connectors for these was because of cost considerations in consumer products. The early RGB computer monitors used BNC connectors. I use BNC for my long analog video and digital audio runs in the wall with patch cords with a BNC at one end and an RCA at the other to go from the wall to the device. But it just goes to show that for short connections almost anything will work.
 

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Quote:
Originally Posted by ChrisWiggles /forum/post/19572487


Almost all the cheap stuff I've ever seen, including the throwaway cables that come with any AV equipment, is coax.

Sure about that? Look closely. Looks like shielded single conductor wire to me.
 

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Discussion Starter · #16 ·
So was the decision to come up with component cables instead of just using a single coax cable cost considerations or was there some other reason? They just kind of seem annoying to deal with in comparison.


I feel like I should clarify that by 'just bought' I mean I just hit order and I bet it hadn't shipped yet.

Quote:
Originally Posted by ccotenj /forum/post/19572211


well, there's no compelling reason to change them just because they are 50 years old...

"If it ain't broke, don't fix it"? I can respect that. Though I did just say I found it strange not that it should clearly have been overhauled. Especially the TRS stuff that is abit over a hundred years old. I'm betting they were also for something completely different.


As far as new cable standards go I like the sound of HDbaseT much better than even HDMI even though all my stuff uses/will use HDMI. (besides, you know, my Dreamcast) The Idea of just going out buying a bunch of ethernet connectors and then just using that spool of 5e cable on a spool collecting dust in my garage to connect literally everything together is awesome. Especially because you don't care if it's 50 plus feet long when HDMI needs to stay relatively short.
 

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Quote:
Originally Posted by Wayne A. Pflughaupt /forum/post/19581936


Technically-speaking, any single-conductor shielded cable is coax.

Nope. The construction of single conductor shielded cable doesn't ensure that the center conductor and the shield remain coaxial through their length, particularly in bends. Maybe quasi-coaxial describes it?
 

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From Wikipedia, coaxial cable is simply defined as “an electrical cable with an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis.”


In other words, any round single conductor shielded cable meets the definition. Poke around the Web and you’ll find that other sources give pretty much the same definition, at least to the point where they start talking about its most common designation and application, namely high-frequency signal transmission. (“Most common” is not the same as “only.”)


Construction is construction. Bending has nothing to do with a cable “remaining coaxial.” What, does it somehow turn into shielded twisted-pair or doorbell wire at that point?



Perhaps instead of “remaining coaxial” what you really meant was “retaining impedance?” That’s another issue aside from the technical definition.


Regards,

Wayne A. Pflughaupt
 

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Quote:
Originally Posted by Wayne A. Pflughaupt /forum/post/19583593


From Wikipedia, coaxial cable is simply defined as an electrical cable with an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis.

And if it is on Wikipedia, it must be right, huh? Looks like you were just groping to find words to support your erroneous argument. If you had read further you would have found this:


"Coaxial cable differs from other shielded cable used for carrying lower frequency signals such as audio signals, in that the dimensions of the cable are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a radio frequency transmission line."
 
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