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Uni Directional Subwoofer Cables - Page 4

post #91 of 189
4/4/10 at 5:06am
Quote:
Originally Posted by Gizmologist View Post

"The shield is NOT used to carry the signal, but rather as a true shield in which any noise that gets "onto" the shield will then be directed to ground (assuming the piece of gear that the has the end of the shield hooked up has a good path to ground. Not all do."

Please show me ANY unbalanced audio INPUT to an amp that does NOT need a shield. As explained at least 3 times. it makes no difference whether you use 1 wire in a twisted pair as the return (and ALL audio circuits need a return of some sort) connected to the sleeve or ground (shield) connection or you use the correct method and use the actual shield. If at ANY point in the interconnect between A and B you use some sort of a conductor connected between the grounds you have a ground between the circuits
Leaving one end of the shield on an UNBALANCED cable does nothing electrically. You can use an unshielded TP for a very short distance in some cases (a couple feet max) before you begin to present the amplifier with extraneous noise /hum. This is WHY we use shielded cables.

Doing that on a truly BALANCED setup is a whole other scenario.


I will try one last time. The shield is NOT needed for the circuit to work. The other wires provide the electrical path.

BTW I never said an unbalanced circuit did not need a shield. I said the shield did not have to be hooked up at both ends. And of course the end that is hooked up, HAS to have a good path to ground, or the whole thing falls apart.

But by the shield not BEING one of the paths, the noise from the outside world does not get onto one of the wire that is actually part of the circuit-as it would if the shield was a conductor.

This way the shield is an actual shield and not part of the circuit path. Such as the chassis around an amplifer. It is not part of the actual circuit (but is still connected to ground), but provides isolation to the internal parts from the outside world.

As I stated before, I have seen this work well, and not at all. It depends on the particular situation and the pieces involved. In no case (that I have tried) was it any worse than a regular guitar cable. But that doesn't mean that it couldn't-nosie can be a weird tricky thing and every situation is different.

You can believe what you want, but unless you have tried it (and yes it may take several tries in different situations with varying results), you cannot say it will have no effect.
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post #92 of 189
4/4/10 at 4:42pm
You really need to look at the circuit again to understand. It makes no difference electrically at all if one end of the shield is free and floating.

If the other end is connected IN ANY WAY WHATSOEVER, to the ground the shield IS in the circuit. It is NOT the ONLY path as you are using one wire in a TP to complete the ground to ground connection. That is why lift the shield on one end of an unbalanced cable and using a TP to complete the same circuit CANNOT and does not alter the ground to ground circuit.

I do have a few years doing audio of every type and ground hunting. problem solving is something I have spent a LOT of time learning. It is my livelihood as well and I make a nice living KNOWING what I am doing.
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post #93 of 189
4/4/10 at 5:46pm
I think it's imperative to follow your heart and choose a profession you're passionate about, and if you haven't found that "spark" yet, if you're not sure what you want to do with your lives - be persistent until you do.
Steve Kerr

To be passionate about ones work is a wonderful thing, this has been a great learning experience. It started with a subwoofer cable with perhaps coaxial cable and RCA connectors and then got into twisted pair and twisted pair with shield. Most everything except for star quad with shielding were discussed. I have been experimenting with it lately and like the effects of having two twisted pair as well as shielding but this probably opens an entirely new can of worms.
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post #94 of 189
4/4/10 at 6:10pm
All I do is check the cable for an arrow pointing one way and that end goes to the sub. No muss, no fuss, no discussion.

Bill
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post #95 of 189
4/4/10 at 6:13pm
Getting back to the OP question, and maybe to clear up some of these misconceptions about noise rejection and hum: The reason that this is done most commonly in subwoofer interconnects is due to the longer wire runs typically used for them. If noise can be caught and reduced at the source end, it is not going to be amplified as much at the sub since the radiated noise has been directed to the ground path back at the receiver instead of being distributed to either end simultaneously. By doing this, for a very low cost, radiated noise can be reduced, albeit only by a small amount. As Giz has pointed out, there may not be a difference electrically. But there would not be an electrical difference if you stuck a pair of coat hangers into the rca plug and kept them from touching each other, and used them to carry the signal from your amp to your sub. How much noise is it going to pick up though? Keep in mind that audio and noise are frequencies that can be radiated, picked up, and amplified by your gear. I am surprised on this forum, that everyone will spend countless hours discussing tweaks and treatments that in many cases cannot get any audible improvement out of your system, but as soon as you mention cables, everyone has to pick side. I dont buy into the high priced cable technology, but this is a simple design technique that can reduce hum to a sub. Since most radiated hum in a household is mostly 60hz radiated from the electrical wiring, it is a potentially useful design can that assist in reducing that noise reaching your sub.
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post #96 of 189
4/4/10 at 6:35pm
maybe he meant a cable that sends a signal to the sub, but no return signal, as when you have a built in filter/by-pass...

pre-amp out to the sub
NO sub back to power-amp in
???

I guess than could be considered 'uni-directional'
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post #97 of 189
4/5/10 at 5:14pm
Gizmologist wrote:

Please show me ANY unbalanced audio INPUT to an amp that does NOT need a shield.

"I think that "return" is more correct than "shield". As some use twisted-pairs for un-balanced interconnects.

But if the return shield or wire is disconnected, the signal will find some other less desirabilia part to return to the source. If no other path is found then no audio.

Sometimes the other path is the power cords, other signal wires or chassis to chassis metal contact.
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post #98 of 189
4/5/10 at 6:19pm
However again I ask for an example of any unbalanced IC that does NOT have a shield aside from a cheap speaker cable that uses RCA or 1/4" phone connectors.

Technically speaking the shield IS a return but as a single ended IC cable will have a phase and a shield they are one in the same on HI-Z unbalanced cables.
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post #99 of 189
4/5/10 at 7:48pm
Lot's of the Kimber Kable unbalanced phono plug interconnects are just twisted pair. See:
http://www.audioadvisor.com/prodinfo...umber=KKSS0147

I'm sure that there are others but I don't follow that kind of stuff!

Technically speaking the shield IS a return but as a single ended IC cable will have a phase and a shield they are one in the same on HI-Z unbalanced cables.

Yes, on a correctly wired co-ax the "return" and the "shield" are the same thing.
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post #100 of 189
4/5/10 at 9:33pm
I was hoping for a real scientifically based product as an example. Using KK 300.00/ 1.5 ft RCA cables with all the associated BS is NOT exactly a ringing endorsement.

I sure wish I could find commercial clients as gullible as anyone who gets suckered by that claptrap. I could retire by noon tomorrow.
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post #101 of 189
4/6/10 at 3:28am
Thread Starter 
I completely realise that some here believe that uni directional subwoofer cables make no difference at all (this scientifically makes perfect sense to me by the way). However, some feel that it does.

Either way I want to make sure that I completely understand this theory so I made something up in photo shop (see attachment).

Could I please ask for verification that I at least have a grasp on the way a uni-directional subwoofer cable is "meant" to work.
LL
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post #102 of 189
4/6/10 at 3:42am
100dB,
Yes that's how a truly directional unbalanced interconnect works.
But it's far from the best choice for an interconnect. Especially a sub-woofer interconnect. Chose a co-ax with a heavy braided shield.

Some balanced interconnects are wired this way or with a small added capacitor.
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post #103 of 189
4/6/10 at 4:02am
Thread Starter 
Kevin, I was under the impression that twisted pair wiring was the preferred choice for subwoofer interconnects and it seems that most the major cable producers do it this way also.

Also, from what was posted earlier (which also makes perfect sense to me), an RCA cable can never be considered a balanced interconnect by nature of it's design.

Edit: By the way, I just looked at the price of those Kimber Kable interconnects. This is what I am sick of! Companies that try to convince the "gullible" portion of audiophiles that a cable is worth that much. It amazes me with all the complexities of a home audio system that people look to the cable to bring about the biggest changes in audio sound stage and imaging etc.

From the link above "It's dynamic, involving, accurate, detailed and harmonically pure," raves Todd Warnke in his review for SoundStage "The Silver Streak sets a new standard for me."

All this from a cable??? What about the AV Receiver/Amp and gorgeous speakers sitting there, do they not make the majority of the impact here?

It is blind robbery! I am all for a high quality cable but it is impossible that a cable can be worth $700 for a 2m length. This is why I want to form the company that I am about to launch as I want to offer the best possible quality that a cable can be, but ask a realistic price. Nowhere near the amount that some of these thieves do. I would estimate a quality 3m Subwoofer interconnect will list for about $25 - $30. I really want to educate my valued customers and provide them with genuine, caring service.

Sorry if this offends those that spend insane amounts of money on their cables but there is a point that crosses the ridiculous line. $700 for a 2m stereo cable is well and truly across the line. I would rather use the money to buy better speakers etc.

**End of rant... Sorry about that, I just get passionate about this kind of thing.**


Question open to everyone...
Is there any reason why one type of cable is better than the other (coaxial vs. twisted pair) for analog audio? And why? Please provide solid facts, I don't want this to turn into an opinion debate.
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post #104 of 189
4/6/10 at 6:14am
Quote:
Originally Posted by 100db View Post

I completely realise that some here believe that uni directional subwoofer cables make no difference at all (this scientifically makes perfect sense to me by the way). However, some feel that it does.

Either way I want to make sure that I completely understand this theory

Despite what some would seem to suggest there is nothing theoretical about wire. What people "believe" does not matter. All that matters is reality and fact. Take what Gizmo posts to the bank. Its fact, not theory.
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post #105 of 189
4/6/10 at 8:50am
I like Kimber Cable even though there cables are overly expensive, Black pearl any one ..
If you Have the money to burn on Expensive Speakers why not buy good quality Audio Cable ..

I have run Kimber 8TC speaker cable shotgun for years and love the stuff..

Cheers...
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post #106 of 189
4/6/10 at 8:57am
Quote:


If you Have the money to burn on Expensive Speakers why not buy good quality Audio Cable

No one has suggested otherwise. Good quality audio cable can be had for well under a dollar per foot.
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post #107 of 189
4/6/10 at 9:37am
So you can get Kimber cable for under A Dollar A foot ..


Cheers...
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post #108 of 189
4/6/10 at 9:49am
Quote:


So you can get Kimber cable for under A Dollar A foot ..

If you say so.

Of course, Kimber isn't the only supplier of cables, there are many many others who supply quality cables at much lower prices...I'm guessing that you just haven't heard of any other maufacturers...shop around, enlighten yourself.
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post #109 of 189
4/6/10 at 10:00am
Try Canare L4E6S. About .25 a ft in the quantity I buy it and about .38 ft retail.

Star quad construction, untinned copper conductors, 98% ultra dense braided shield, uber flexible jacket available in 10 colors, and most important, THIS is the cable (and similar) used by the recording studios to CREATE what you listen to and it is the professional industry standard for broadcast and EFP and ENG TV, and movie production.

This is what is used to create the 2,3,4,5,7,9.1 soundtracks and they use hundreds of thousands of feet.

This cable is used equally well all over the world for LO-Z dynamic mics, condenser mics, balanced +4 line level, ICs, control and clocking data, field intercoms, DMX multichannel lighting control (digital) so it has a fairly well proven track record.

I doubt your home system can, in any way, strain the capabilities of this cable.
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post #110 of 189
4/6/10 at 2:19pm
The Canare L4E6S is excellent cable and I use it often. I may have to shop around though, that price is very good! I have not used it for DMX lighting but will give that a try if the need arrises.
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post #111 of 189
4/6/10 at 3:07pm
Thread Starter 
Quote:
Originally Posted by 100db View Post

Question open to everyone...
Is there any reason why one type of cable is better than the other (coaxial vs. twisted pair) for analog audio? And why? Please provide solid facts, I don't want this to turn into an opinion debate.

Could anyone offer any thoughts to this? Kevin mentioned above that coax. is a better choice for a subwoofer cable but this seems to go against what most cable manufacturers do.
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post #112 of 189
4/6/10 at 3:14pm
Quote:


Is there any reason why one type of cable is better than the other (coaxial vs. twisted pair) for analog audio?

Coax cable should be used for unbalanced interconnects. Twisted pair for balanced interconnects. This can be for either digital or analog signals.
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post #113 of 189
4/6/10 at 3:15pm
Thread Starter 
Quote:
Originally Posted by duvetyne View Post

Coax cable should be used for unbalanced interconnects. Twisted pair for balanced interconnects. This can be for either digital or analog signals.

So that would mean any RCA cable should be using coax cable? As from what I absorbed earlier, all RCA cables are considered unbalanced.
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post #114 of 189
4/6/10 at 3:21pm
Quote:


So that would mean any RCA cable should be using coax cable?

Depends on the application.

RCA originally used Cinch connectors (the things that everyone calls RCA connectors) for unbalanced audio. Since then they've been used for RF and video signals. The connector itself is a coaxial connector.

Quote:


all RCA cables are considered unbalanced.

Non symetrical two conductor cables (such as coax) are unbalanced, meaning, the characteristic impedance between the signal carrying conductors and ground is not the same.
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post #115 of 189
4/7/10 at 7:56am
It figures the guys who love to go around bashing cables know very little about them outside of their particular experience in usage.

Gizmo argues about the function of a shield, when all he really knows is how to connect it (or frig it) so there is no hum, as if that were the only criteria for a shield to be properly functioning. This is a very common basic understanding but only touches upon low frequency noise rejection, namely 60 Hz. He also thinks that a twisted pair shielded should not be used as a single ended connection, but if you must that you should connect the twisted pair together at both ends for 'hot (double up on the gauge), and only use the shield for neutral/ground, rather than the proper method of using the twisted pair for the audio, and the shield solely as a shield. I take it you've been doing this for 40 years. Try using a coaxial in car audio..

duvetyne, bluesky636, DaBuzzard, Weasel9992, Easyaspie, Av Doogie, Lhasa-lover, geekhd, Bigus, and Ratman, all believe that directional markings are BS or (until now) only used as marketing hype, samo samo from most of these guys. In reality the markings signify the proper direction given the shields configuration or connection point, usually to the source, as Ivan Beaver and ChrisWiggles so correctly attempted to point out and had to argue for even tough they understood this the best.

So to 100db, if you're truly thinking about building cables for others, suggest you look to a more solid reference than these forums for your humble beginnings, for everyones sake.
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post #116 of 189
4/7/10 at 8:58am
From you: "

Gizmo argues about the function of a shield, when all he really knows is how to connect it (or frig it) so there is no hum, as if that were the only criteria for a shield to be properly functioning. This is a very common basic understanding but only touches upon low frequency noise rejection, namely 60 Hz. He also thinks that a twisted pair shielded should not be used as a single ended connection, but if you must that you should connect the twisted pair together at both ends for 'hot (double up on the gauge), and only use the shield for neutral/ground, rather than the proper method of using the twisted pair for the audio, and the shield solely as a shield. I take it you've been doing this for 40 years. Try using a coaxial in car audio.."

Please show me where I said anything of the sort.

What I said was and I CAN PROVE IT, was that if any IC cabling between 2 devices where a ground loop exists (there is a an AC voltage potential between the grounds of the 2 devices) that dropping the shield on a cable yet using one wire of a TP to electrically complete the same circuit will not in any way improve the function as the AC potential STILL exists. It makes zero difference if the ground conductor is a single wire or a shield.

You might want to learn a bit more about audio interconnects and the pros and cons of the various methods and their limitations. You see my job is to build systems that work 100% of the time, not sell Hyperbole brand wire that actually has nothing special about it.

Would you care to explain to our friends here why NO studio or production facility uses anything aside from the industry standard suppliers of stock cables?

BTW I (we) are still waiting for you to post the actual specifications for any of your magical mystical "Wallet Drainer" series of cables. You pick a cable and I' will pick one made by a legit manufacturer and let's post all the details.
Sound like a plan? Please don't bother posting anything in the way of a delay or deflection attempt, just the data please.
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post #117 of 189
4/7/10 at 9:24am
Quote:
Originally Posted by Joe Skubinski View Post

So to 100db, if you're truly thinking about building cables for others, suggest you look to a more solid reference than these forums for your humble beginnings, for everyones sake.

Joe Skubinski, aren't you the one who sells boutique cables? Your pocket depends on sales so whatever you post here wouldn't be something that can compromise your income level, even if they are facts about audio cable. Am I right?
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post #118 of 189
4/7/10 at 9:27am
Joe Skubinski is a salesdroid with no basic knowledge of electronics....evident in every thread he posts in. Who would take technical advice from him?
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post #119 of 189
4/7/10 at 10:11am
Quote:
Originally Posted by Gizmologist View Post


Please show me where I said anything of the sort.

You might want to learn a bit more about audio interconnects and the pros and cons of the various methods and their limitations. You see my job is to build systems that work 100% of the time, not sell Hyperbole brand wire that actually has nothing special about it.

>>>>>>

OK mun, you asked for it. Do you know Giz that I engineer cable for a living? I mean the actual cables themselves, from the inside out, as well as finished terminated products. I say this only in the interest of saving 100 more posts of you continuing to argue your point.

Try googling ' twisted pair magnetic field rejection ' for starters in reading about what you term 'electrically the same'. Some results are this, or a bit more technical here.

It's obvious from your posts what you know. I did pro audio and broadband RF when I was a teenager- I know the tricks, I know what I thought I knew back then. It's obvious to me that you never really moved beyond that, you probably never had the need to. Suggest you try listening instead of arguing- it's a whole different world.

>>>

Quote:
Originally Posted by 100db View Post

In all fairness Gizmologist, I believe the marketing aims at a theory of reducing interference or "hum".

Quote:
Originally Posted by Gizmologist View Post

It is beyond ANYONE's understanding because it is 100% BS

Above shows how your teachings are applied.

Quote:
Originally Posted by Gizmologist View Post

What we are trying to do is to educate people. We hope they actually learn some basic physics, basic audio and most important, how to spot 100% BS, claptrap, garbage, nonsense, sheer stupidity, lunacy and to take the appropriate steps and flush it. Flush it twice please.

The above of course a second response to directionality (shield polarity).

Quote:
Originally Posted by Gizmologist View Post

If someone assembles an RCA (unbalanced) cable using 2 wires in a shield and twists those 2 wires together at each end to solder them to the center pin of an RCA male connector.

Above shows how you are accustomed to using twisted pair shielded cable.

There is ZERO difference between a single wire in a pair and both wires in a pair connected to the same points on the connectors.

See google results on twisted pairs- there is a HUGE difference in the way the cable rejects noise.

Quote:
Originally Posted by Gizmologist View Post

Trust me on this. I do read and understand schematics rather well. I make a nice living drawing them, using them, and building rather extensive AV systems for many years.

As I said earlier, the picture shown with a single ended cable connection (RCA) is of absolutely zero difference electrically from a straight through soldered connection shield to shield tie point on the connectors[/b]. [b]There is zero benefit OR electrical change in the IC circuit between 2 devices so connected. NONE.

Same as above.

Anyone who touts that has very little experience in the real world of audio interconnects. The ONLY benefit to lifting one end of a shielded pair is IF and ONLY if the devices are using balanced input/output connections where neither the phase nor the return is referenced to ground AND there is a low voltage potential difference between the chassis or signal grounds of the aforementioned units.

Single ended RCA to RCA is electrically the same no matter what you do to the cable. As long as there is a shielded connection and phase, the cable functions identically to an off the shelf RCA cable.

Again above, you are confirming your lack of understanding on twisted pairs.

Quote:
Originally Posted by Gizmologist View Post

You really need to look at the circuit again to understand. It makes no difference electrically at all if one end of the shield is free and floating.

I do have a few years doing audio of every type and ground hunting. problem solving is something I have spent a LOT of time learning. It is my livelihood as well and I make a nice living KNOWING what I am doing.

Shows a lack of understanding about shields.
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post #120 of 189
4/7/10 at 10:17am
Joe, why don't you post the links to your engineering papers, patents and designs? Impress us....since you haven't done so with the 'knowledge' you've displayed here.
Asserting that you 'know what you're doing'....and then falling flat on your face in every technical discussion doesn't convince anyone that you know anything.
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