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jc1k66 11-14-2012 03:43 PM

Wiring Interference Question
 
Finishing a room in my basement, and there will be several types of wall stud wiring and junction outlet going on, including:

- AC
- Cable Coax
- RCA analog audio
- Cat6 Ethernet
- Audio Optical
- USB
- Speaker wire
- HDMI

My general goal is to keep AC lines at least 2 inches away from all other wires at all times (most of the time 1 ft away). Other than that, though, I'm not sure what to expect or mitigate ahead of time as far as interference issues. Any ideas or general guidelines? (i.e., its ok to couple cat6, optical, usb, hdmi together, however keep AC, coax, speaker, RCA at least X inches away from each other and everything else)

Thanks for any advice...

tylernt 11-14-2012 04:17 PM

Well you don't need to worry about the optical, it's immune to RFI/EMI and generates none of it's own. Run it wherever.

If you haven't purchased your patch cables yet, get ones that have a big lump between the ends. That's a magnetic toroid, which helps filter out interference.

You can cross 120VAC with digital data cables (USB, Cat6, HDMI) at right angles. It's just parallel runs that cause problems.

Digital data should all play nice with each other even in close proximity, but all will inject noise into speakers and RCA cables to some degree.

Speaker wire could conceivably induce noise in RCA too, dunno if it's significant.

The coax cable I'd put off by itself. It's susceptible to RFI and generates RFI of it's own. Use the good RG6 instead of crappy RG59.

ddawg16 11-14-2012 04:23 PM

Tyler pretty much coverd the bases.....

However....I would rethink your USB. That is not really intended for long runs. Noise is not your issue.......you might want to rethink running USB in walls. I believe the spec for USB 2.0 is a max of 5m....or about 15'.

jc1k66 11-14-2012 04:42 PM

Thanks for the quick feedback.

What you say all makes sense. Can you quantify "off by itself", a little, specifically with regards to the RCA, speaker, and coax that might cause trouble with other cables? The studs are 3.5" wide, so about 2" is the max I can separate them out in some cases as they pass each other. Can I do something to further shield the proximity in brief places where the pass closely?

Regarding USB, noted and understood. I had the spare cable, key stones and junction outlet spots. It was just to possibly USB connect a computer directly to a TV 15 ft away (through the wall), but no real specific planned use. I was just going to lay the wire. If I find a use and it works, great. If not, no biggie.

jc1k66 11-14-2012 05:15 PM

Reading up a little more on this USB 2.0 distance limitation, apparently it is 16 ft (5m). If the total USB distance between the computer and TV is <= 16ft, including:
- USB cable from comp to keystone 1
- USB cable though wall from keystone 1 to keystone 2
- USB cable from keystone 2 to TV +
--------------------------------------
<= 16 ft

Will this likely work? Or am I just wasting my time with this USB endeavor, of which I am not sure I am even going to use.

Thanks...

mysterd429 11-14-2012 05:50 PM

I've never done this before, but you might try using a USB repeater, like is described here, to get the length required.

tylernt 11-15-2012 09:34 AM

Quote:

Originally Posted by jc1k66 (Post 1052190)
What you say all makes sense. Can you quantify "off by itself", a little, specifically with regards to the RCA, speaker, and coax that might cause trouble with other cables?

I don't have any hard data, except that the longer you run cables together, the greater chance of interference. If this is just going 4ft from a wall-mounted TV to jacks in the lower part of the wall, you probably won't see any issues.

Quote:

The studs are 3.5" wide, so about 2" is the max I can separate them out in some cases as they pass each other. Can I do something to further shield the proximity in brief places where the pass closely?
Shielded RCA cables are readily available and probably a good idea. The rest is probably fine with 2" separation between digital and audio. You don't need an expensive HDMI cable, just look for one that's "thick" which indicates good shielding. Same goes for USB, thicker the better. Shielded Cat6 ("STP" Shielded Twisted Pair) is expensive and overkill, I wouldn't bother unless you're going 100'.

As for coax, the cable just by itself usually isn't too "leaky", in fact you can buy Cat6+Coax bundled together. It's the connectors where the noise (both spewed out and injected) is the worst, so use high-quality terminations and take care when installing them. Use threaded coax patch cables, not the push-on type.

You might consider having two wall plates placed in the left and right of a stud bay (typically 16" on center): one for digital, one for audio. That would give you over 10" of separation.

ddawg16 11-15-2012 09:46 AM

Use a good shielded RCA cable and you will be fine.

As for speakers....in reality, the speaker wire is more likely to cause interference in other wiring vs other stuff affecting the speakers. Your driving those with a low impeadance source...they will not be an issue......(translation, you don't need to waste money on Monster cables)

Dave632 11-15-2012 10:01 AM

The AC line is most likely to affect the speakers, those are the two I'd want to keep as far apart and as non-parallel as possible.

Maybe enclose the AC in metallic conduit?

gregzoll 11-15-2012 10:01 AM

Forget optical, it is a dead technology. For HDMI, pull Cat-6, rca audio and video use rg-6. In reality, all you need where the tv is going, is just one hdmi interface, everything else would connect to the AV receiver.

Evstarr 11-15-2012 03:52 PM

IF you have newer equipment. Cables are cheaper than tvs an receivers if you don't. But plan for the new stuff now while you're feeding the old.

gregzoll 11-15-2012 08:58 PM

Quote:

Originally Posted by Evstarr (Post 1052961)
IF you have newer equipment. Cables are cheaper than tvs an receivers if you don't. But plan for the new stuff now while you're feeding the old.

If they do a central wiring scheme, everything will connect at the point they have their AV Receiver, Cable or Satellite box/dvr, Blu-Ray player, Xbox 360 or PS3, HTPC. From there, you would have a single HDMI run to your TV mounted on a wall, and speaker wiring going to the points that the speakers will be.

If it is going inside a stand that the tv will be sitting on, everything will be in the cabinet under the tv, with the speakers next to it, and only wiring that would need to be run, is surround speaker wiring, ethernet, coax for satellite or catv.

To the OP, you really need to look at the room designs at AVSforum.com to see what people have done, and what a really good home theater setup is like, not something just thrown together. Wiring it up is not hard, it is just that if you do not have a written plan and schematic where everything is going, you are going to find and run into trouble during the middle of your install.


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