Unbalanced audio cable shielding

[Skwisgaar]

It is accepted practice in the industry to have the negative conductor separate from the shielding on unbalanced cables. It doesn't cost much to obtain cables like this. But I am wondering, does it really make a difference?

There are some situations in the pro audio world (microphone cables with phantom power) that you are using the shield as the negative conductor.

 

[Swerd]

It is accepted practice in the industry to have the negative conductor separate from the shielding on unbalanced cables. It doesn't cost much to obtain cables like this. But I am wondering, does it really make a difference?

Not in my experience. I've used both coax cables and shielded two-conductor cables for audio connections, and was never aware of an audible difference. The only industry standard I am aware of is using coax cable with 75 ohm impedance for video connections.

 

[Skwisgaar]

I didn't state in the OP, but thought it would be understood, is the expected audible difference is in the noise level of the signal.

Just because a cable is coax doesn't mean that the shield is the negative conductor. For the coax cables that I have looked at the negative conductor is shaped like an inner shield. It is difficult to find cables in this day and age where the shield is used as a negative conductor. The only examples I can think of are microphone cables with phantom power, and stereo headphone cables.

 

[highfigh]

It is accepted practice in the industry to have the negative conductor separate from the shielding on unbalanced cables. It doesn't cost much to obtain cables like this. But I am wondering, does it really make a difference?

There are some situations in the pro audio world (microphone cables with phantom power) that you are using the shield as the negative conductor.

The shield is not usually used as an audio conductor in pro audio balanced applications or microphones- the plug (XLR or TRS) uses Pin 1 (sleeve) for the shield and this is usually grounded. Pin 2 (Tip) is the normal signal carrier and pin 3 (ring) is for the inverted signal. Sometimes, Pin 1 needs to be lifted and sometimes, it needs to be combined with Pin 3 to unbalance the signal. Some mics need a battery or some other source of power in order to work (condensor mics) and the current uses Pins 2 and 3 for this. If a mic is connected and doesn't need power, activating Phantom power (called that because the battery isn't in the mic and the source is somewhere else) will release the magic smoke from the mic.

Shielded, twisted pair should only have the shield connected to the negative at one common end and that is the preamp, integrated amp or receiver (stereo or AVR). In this case, the shield acts as an antenna for the noise and when it reaches the common piece's grounded chassis. If the input/output jacks' shield ferrules are isolated from the chassis, this won't work but the noise will still be connected to the circuit's negative, which is grounded at some point.

Whether it makes a difference depends on the strength of the interference, distance to the field(s), signal strength on the cable, length of cable and whether the cable is running parallel (physically) to a noise source.

 

[highfigh]

I didn't state in the OP, but thought it would be understood, is the expected audible difference is in the noise level of the signal.

Just because a cable is coax doesn't mean that the shield is the negative conductor. For the coax cables that I have looked at the negative conductor is shaped like an inner shield. It is difficult to find cables in this day and age where the shield is used as a negative conductor. The only examples I can think of are microphone cables with phantom power, and stereo headphone cables.

If it has one conductor at the center, the shield IS the negative conductor unless the equipment is stacked together and bonded in which case, the shield is only used as a shield.

Typical cables with RCA plugs use the shield as the negative conductor. That's why ground loops occur so often.

What cable are you referring to- post the brand and item number.

 

[TLS Guy]

highfigh said: -

If a mic is connected and doesn't need power, activating Phantom power (called that because the battery isn't in the mic and the source is somewhere else) will release the magic smoke from the mic.

This should not happen if things are wired correctly. The elegant thing about phantom powering is that the + 48 volts is on pins 2 and 3. Since they are at the same potential, no can flow between them. Ground is the neg. So both pins 2 and 3 have the 48 volts above ground but not between each other.

That allows you to use a mix of phantom and non phantom powered mics from the same desk at the same time. I have done this for years, and never had smoke, and my mics are fine.

So if you have seen what you say, someone did something improper.

Phantom powering is very elegant and robust.

 

[highfigh]

highfigh said: -

That's assuming the mic is supposed to be used with phantom power. A dynamic mic doesn't like this and I have seen dynamic mics smoke when the switch was in the On position.

If everyone would make sure of what they were using, this wouldn't happen.

 

[TLS Guy]

That's assuming the mic is supposed to be used with phantom power. A dynamic mic doesn't like this and I have seen dynamic mics smoke when the switch was in the On position.

If everyone would make sure of what they were using, this wouldn't happen.

Sorry, but if it smokes it is not true phantom powering. It is called phantom, because it is unseen. It was set up just so you could use phantom mikes and M/C and ribbon mikes off the same deck. I have done this numerous times.

If it is proper phantom powering there is no voltage across the V/C of a moving coil mic as both ends of the coil are at the same potential so NO current can flow through the coil.

If you have had trouble, then you have used some off brand non professional muck up. I can assure the deck pictured above can supply phantom condensers and moving coil mics at the same time, with phantom powering on at all XLR mic inputs.

I routinely use to use my Neumann and Shure phantom studio condensers and my two way M/C AKG studio mics at the same time when I was doing the broadcast for the local public radio station. No smoke or incidents, because that is the way true phantom powering is designed.

The same goes for that RME mixer/DAC to the right of it.

Look it up and see how phantom powering is supposed to work, it is very elegant and simple.

 

[highfigh]

Sorry, but if it smokes it is not true phantom powering. It is called phantom, because it is unseen. It was set up just so you could use phantom mikes and M/C and ribbon mikes off the same deck. I have done this numerous times.

If it is proper phantom powering there is no voltage across the V/C of a moving coil mic as both ends of the coil are at the same potential so NO current can flow through the coil.

If you have had trouble, then you have used some off brand non professional muck up. I can assure the deck pictured above can supply phantom condensers and moving coil mics at the same time, with phantom powering on at all XLR mic inputs.

I routinely use to use my Neumann and Shure phantom studio condensers and my two way M/C AKG studio mics at the same time when I was doing the broadcast for the local public radio station. No smoke or incidents, because that is the way true phantom powering is designed.

The same goes for that RME mixer/DAC to the right of it.

Look it up and see how phantom powering is supposed to work, it is very elegant and simple.

I know how it's supposed to work, but on that occasion, things converged to cause this and I think someone's desire to save money was behind it. The mic was an off-brand thing that might have cost $50 to replace. I have some Audio-Technika mics that can use a battery or phantom and I've never had a problem with those.

What recording software are you using and why do you have so many remote controls?

 

[TLS Guy]

I know how it's supposed to work, but on that occasion, things converged to cause this and I think someone's desire to save money was behind it. The mic was an off-brand thing that might have cost $50 to replace. I have some Audio-Technika mics that can use a battery or phantom and I've never had a problem with those.

What recording software are you using and why do you have so many remote controls?

If a mic smoked connected to phantom powering, then it was a POS that deserved to be smoked and discarded.

I use Steinberg WaveLab 6. Actually I don't use remotes much. I can't be bothered to mess with a universal remote.

For the TV I just use the remote to switch it on an off. My pre/pro is close by me and it is easier to just get up and use old fashioned knobs. I use the remote for the BD player some and the Direct TV remote. I never use the remote for the Marantz disc players, always manual. For my HTPC I use a full sized wireless key board and love it. The rest does not have remotes, except a couple of tape machines that have hard wired remotes.

I really don't like remotes and find them a nuisance more than help more often than not. Things were just fine before they came on the scene.

Now if everyone would cooperate so I could run everything easily and quickly from a smart phone or tablet, then count me in. It could use the screen to show connections and all current settings.

My view of remotes is that it is bad awkward interim technology. We need much better, to improve on what we had 50 years ago.

 

[highfigh]

If a mic smoked connected to phantom powering, then it was a POS that deserved to be smoked and discarded.

I use Steinberg WaveLab 6. Actually I don't use remotes much. I can't be bothered to mess with a universal remote.

For the TV I just use the remote to switch it on an off. My pre/pro is close by me and it is easier to just get up and use old fashioned knobs. I use the remote for the BD player some and the Direct TV remote. I never use the remote for the Marantz disc players, always manual. For my HTPC I use a full sized wireless key board and love it. The rest does not have remotes, except a couple of tape machines that have hard wired remotes.

I really don't like remotes and find them a nuisance more than help more often than not. Things were just fine before they came on the scene.

Now if everyone would cooperate so I could run everything easily and quickly from a smart phone or tablet, then count me in. It could use the screen to show connections and all current settings.

My view of remotes is that it is bad awkward interim technology. We need much better, to improve on what we had 50 years ago.

At times, universal remotes are the bane of my existence. URC falls all over themselves, telling us that they have the largest code library and then, when time is tight, I find that the equipment I need to control isn't in the list or the codes are faulty, named incorrectly, missing or the software crashes repeatedly while I'm trying to create/change the program. The recently rolled out a "New and improved" way for dealers to have their programming accelerator when they don't buy directly from URC and less than six months later, pulled the plug on it. Programming RTI is even more tedious, the big brands (Crestron, AMX, Control 4) require buy-in orders that are far more than smaller specialized dealers can justify and consumer brands like Harmony don't want to do the things custom integrators want/need. The irony is that Harmony's code base IS the most complete and they have been more helpful in analyzing problems than anyone. They don't communicate well, though.

When equipment has IP control, I like to use that- it tends to work pretty well.

My background isn't in programming but I refuse to believe that the way the current state of remote controls is the state of any kind of art. Now, a company called On Controls/iRule has a program that uses Global Cache controllers, but it operates on the Cloud, which is a problem because it uses the cloud for operation, not programming. That's a problem for the house I'm working on- there's no guarantee that internet connectivity will be consistent in that location (very remote location) and without that, it doesn't work at all. It uses only mobile devices from Apple and Android. Not many dealers, yet.

Here's a link- it may do what you want. It does two-way communication, variables, hidden navigation bar and panel sharing.

http://www.iruleathome.com/irule-builder/the-software

 

[Alex2507]

http://www.bluejeanscable.com/articles/shielding.htm

 

[TLS Guy]

At times, universal remotes are the bane of my existence. URC falls all over themselves, telling us that they have the largest code library and then, when time is tight, I find that the equipment I need to control isn't in the list or the codes are faulty, named incorrectly, missing or the software crashes repeatedly while I'm trying to create/change the program. The recently rolled out a "New and improved" way for dealers to have their programming accelerator when they don't buy directly from URC and less than six months later, pulled the plug on it. Programming RTI is even more tedious, the big brands (Crestron, AMX, Control 4) require buy-in orders that are far more than smaller specialized dealers can justify and consumer brands like Harmony don't want to do the things custom integrators want/need. The irony is that Harmony's code base IS the most complete and they have been more helpful in analyzing problems than anyone. They don't communicate well, though.

When equipment has IP control, I like to use that- it tends to work pretty well.

My background isn't in programming but I refuse to believe that the way the current state of remote controls is the state of any kind of art. Now, a company called On Controls/iRule has a program that uses Global Cache controllers, but it operates on the Cloud, which is a problem because it uses the cloud for operation, not programming. That's a problem for the house I'm working on- there's no guarantee that internet connectivity will be consistent in that location (very remote location) and without that, it doesn't work at all. It uses only mobile devices from Apple and Android. Not many dealers, yet.

Here's a link- it may do what you want. It does two-way communication, variables, hidden navigation bar and panel sharing.

http://www.iruleathome.com/irule-builder/the-software

Sorry the delay in getting back to you, but Spring is a busy time in lakes country. I have been servicing boats and getting ready for the summer lakes season.

That iRule looks interesting, but I think the site is awful.

I understand the set up, but I don't understand why it needs a handset. It seems it should control from a laptop, smartphone or tablet.

It looks to me as if the devices are controlled from a unit that can have Wi-Fi or wired connection, and this plugs into the IR sockets of the units to be controlled. Is that correct?

It is not that expensive.

My Direct TV DVR does not have an IR in or out sockets. I am eligible for an upgrade though.

The ones that do are my Marantz AV 8003, Marantz DV 9600, Oppo BD-83 and my Panasonic Plasma TV. The only other item with a remote is my DAT player, but this is very seldom used, and I would not use the remote anyway.

Downstairs I just have the TV a Sony Bravia, another Direct TV DVR and a Panasonic BD player.

At our Eagan residence everything is remote. The TV, Comcast DVR, Panasonic BD player and a Sony Media player. That is where a system like this would be a help, especially for the Sony media player that is a pain to use from the small two sided remote.

No problem with Internet connection, especially at the lake where it is fiber 25 MB up and down.

Any further suggestions, you have especially about the hardware, that goes with it would be welcome. Again, their site is awful, which does not inspire confidence.

 

[highfigh]

Sorry the delay in getting back to you, but Spring is a busy time in lakes country. I have been servicing boats and getting ready for the summer lakes season.

That iRule looks interesting, but I think the site is awful.

I understand the set up, but I don't understand why it needs a handset. It seems it should control from a laptop, smartphone or tablet.

It looks to me as if the devices are controlled from a unit that can have Wi-Fi or wired connection, and this plugs into the IR sockets of the units to be controlled. Is that correct?

It is not that expensive.

My Direct TV DVR does not have an IR in or out sockets. I am eligible for an upgrade though.

The iRule DOES use iPhone/iPad- I don;t remember seeing any other hand-held controller that's not an i-Device or Android.

I might see if I can get some additional work servicing boats- I'm tired of dealing with video. I like working with audio, but all of the flash in the pan garbage is really boring me.