XLR and Cat5 cable

[logmedia]

Hi Everyone,

We're getting ready to rewire our worship platform to prepare for the future. We are starting to go digital and as a result will be running both XLR cable and CAT5.

The question I have is do we need to have any seperation between the 2 types of cable to prevent any kind of interference?

Thanks,

Mike
Lord of Glory Church
Grayslake, IL

[shayward]

We stuck all of our XLR cable in metal conduit because it seemed like the thing to do. I've had VGA interfere with XLR cable in very long parallel runs so it stands to reason that you should give a few feet of separation at least just to be safe.

[DrowningnHim17]

The CAT5 should be immune to most interference, especially that of a line level signal. For example, I recently had to pull some more cat5e through the roof down a hallway at the church and had no other option but to run it right through a snakes lair of 220 and 460 3 phase wires and I have no interference whatsoever. Oh and not to mention all the fluorescent ballasts its right over as well.
But like Shay said, its better to be safe than sorry.

[Brent Bauman]

AV industry best practice is that you would want to maintain some separation between your cable types... It's recommended to run these in different pipes.

This is especially true of audio cable used for microphone level sound. The issue is that if you have any induction of noise into the microphone audio prior to the pre-amp stage of your mixer you will certainly be amplifying the noise in addition to the microphone signal.

This is also true when you run mic and line level signals and especially when you run mic and speaker level signals.

FWIW.

[shayward]

The CAT5 should be immune to most interference

Absolutely. It's more the XLR run that I'd be concerned about

After all... noise on Ethernet gets translated into some lost packets now and again. Most people wouldn't even notice. But noise on XLR gets translated into acoustic sound. Not good

[Brad Weber]

Originally Posted by logmedia

We are starting to go digital and as a result will be running both XLR cable and CAT5.

The question I have is do we need to have any seperation between the 2 types of cable to prevent any kind of interference?

Originally Posted by Brent Bauman

AV industry best practice is that you would want to maintain some separation between your cable types... It's recommended to run these in different pipes.

Actually, the cable type has minimal impact on the separation, it is the signal type that is the primary factor. The problem is that 'CAT5' and 'XLR' in the OP refers to a cable type and connector type respectively, neither references the signal being carried and both are commonly used for a variety of signals. For example, they could both be referencing line level audio, which would then require no separation. Or the 'XLR' runs may no longer be used for mics once a digital console is installed, so separating them as mic lines might be pointless. So think more in terms of what signals are potentially involved.

Originally Posted by logmedia

We're getting ready to rewire our worship platform to prepare for the future.

What do you mean by 'rewire' and how extensive is the work? It is pretty typical that the cabling paths available from the platform to the mix position and any other equipment spaces will be a major factor in determining cable groupings and separation. I have a current project where we are having to make numerous compromises on these issues simply because we are trying to work within the existing conduit. So whether you may have a similar situation or if you are able to add new conduit or paths to support whatever you define can definitely be a factor.

Also keep in mind that if you are running outside of conduit that could not only affect cable separation, it could also affect the cable type as plenum rated cable may be required in some situation where cabling is run outside of conduit.

[shayward]

Actually, the cable type has minimal impact on the separation, it is the signal type that is the primary factor. The problem is that 'CAT5' and 'XLR' in the OP refers to a cable type and connector type respectively, neither references the signal being carried and both are commonly used for a variety of signals.

Excellent point.

Still, cables with 3-pin XLR connectors in an audio system typically (I'd dare say 99% of the time) carry balanced analog audio signals at microphone or line level.

And CAT5E cables in an A/V system typically carry data signals (Ethernet, RS232, RS485, DMX). Other times it may carry VGA signals (which are noisy), telephone (analog or digital), and low-voltage relay/control.

[Brad Weber]

Originally Posted by shayward

Still, cables with 3-pin XLR connectors in an audio system typically (I'd dare say 99% of the time) carry balanced analog audio signals at microphone or line level.

Which reinforces the point, you typically want to separate mic from line but not necessarily mic from mic or line from line, so it being an XLR may narrow it down but doesn't really provide the relevant information. Three pin XLRs are also used for standard intercom connections which carry DC power as well as audio and XLRs are not limited to three pins, I have often used four, five and six pin XLRs for purposes other than audio.

Originally Posted by shayward

And CAT5E cables in an A/V system typically carry data signals (Ethernet, RS232, RS485, DMX). Other times it may carry VGA signals (which are noisy), telephone (analog or digital), and low-voltage relay/control.

When CAT5 is used for VGA, or any video signal, it may also be carrying line level audio. I have also seen RF distribution via CAT5 and increasingly hear of people using CAT cable for many inventive uses. The biggest issue is whether the cable is carrying is network related or point-to-point, while interference, crosstalk, etc. may not be an issue, where they need to go may differ.

That leads into that sometimes separation is as much a functional issue as a technical one, from where things run to who installs and services it there can be many more practical reasons for grouping or separating specific cables. For example, Ethernet and low voltage or serial control may have no technical problem running together but you may want to physically separate the AV and data system components for other reasons. Or you probably want to separate mic and line for any long runs but may run them together for a short distance if it is necessary to fit in the conduit available.