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PostPosted: Fri Jul 01, 2011 3:30 am 
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Location: Seattle, WA
Hi,

This is sort of a noob question. Sorry for the preamble...

Long time. I have a home studio in Seattle. And by that I mean, my home -is- my studio. Only one room is what one would call 'proper' (absorption/isolation) but I actually -record- in every room. Eg. one bedroom has a nice wood floor so that's the drum room and a large bathroom is an 'echo chamber' and another room is set up for people to come over and record bvox... and so on. Up until now, this has meant dragging one big snake around as needed. Which has grown tiresome.

Years ago, I ran conduit under the house and a panel to each room for Cat 5. Now I want to add audio to each room as well on the same panels (new jack plates, of course).

WHAT I WANT
1. I want to have XLR wall connectors and run balanced cable in the same conduit as the current twisted pair. One room will need 6 channels (drum room), one will need 4, and the others will need just 2.

2. And IF POSSIBLE, though this is NOT a deal-breaker, I'd like to have a stereo headphone connector in each room so I can have a monitor mix.

And IF I WERE ASKING FOR THE MOON, I'd also want one unbalanced (1/4") jack for plugging in a geetar, rather than having to drag around a DI box... But I have no idea how that would be possible without $$$$$.

3. And above all I need it to be CHEAP as possible. I don't want crap and I'm willing to do things properly, but this is a total 'budget' deal.

4. Oh... and on that note... to save money, I'm planning on 'multing' runs... ie. wiring the same connection in parallel in each room---since there will NEVER be a case where two people could accidentally plug into the same channel.

OK, so my questions:
1. I'm assuming what I want is cable like this: http://www.redco.com/shopexd.asp?id=541 (Canare L-2B2AT Install Cable) and that I can use it for the mic, line -and- if I do it, the headphone signals right?

2. That Canare cable is the cheapest and thinnest. But prices are -all- over the map. Some mogami I've seen @ almost $1 per foot. Is the Canare OK for my application? Remember, it's going to be permanent so it's not like a stage snake that will be rolled around a lot. All I care about is to not degrade the signal.

TIA,

---JC


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PostPosted: Fri Jul 01, 2011 5:43 am 
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Location: Old Tappan, NJ USA
consider multiple pair Mogami (or similar) low capacitance digital plenum wiring. then put a small headphone amp(s) in the rooms so you're only running audio or line level signals. this way you can get enough pairs into each room easily and run the in and out signals without using speaker level voltage...

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PostPosted: Fri Jul 01, 2011 6:21 am 
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Location: Seattle, WA
Thanks. Any recommended vendors?

And... Probably Totally Stupid Question: Does each 'pair' still have a 3rd wire or is there some other method for dealing with the ground?

Cheers,

---JC

gullfo wrote:
consider multiple pair Mogami (or similar) low capacitance digital plenum wiring. then put a small headphone amp(s) in the rooms so you're only running audio or line level signals. this way you can get enough pairs into each room easily and run the in and out signals without using speaker level voltage...


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PostPosted: Mon Jul 04, 2011 3:16 am 
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you get it with the shielding wrap on each pair. you are shooting for 22-24awg and 12-18pf/ft. (~$1.35/ft). you could typically go lower on the capacitance (which impacts your HF) with 8 or 12 pair but then have to run more cables...

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PostPosted: Mon Jul 04, 2011 4:03 am 
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gullfo wrote:
you get it with the shielding wrap on each pair. you are shooting for 22-24awg and 12-18pf/ft. (~$1.35/ft). you could typically go lower on the capacitance (which impacts your HF) with 8 or 12 pair but then have to run more cables...


Got it. That doesn't seem to be that much of a $ savings over bundling separate wires, but it does sound a lot more convenient.

QUESTION: If I go this route can one of the pairs handle a headphone signal from a 75w amp... or should that be run as a separate cable?

Thanks!

---JC


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PostPosted: Wed Jul 06, 2011 5:23 am 
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i'd suggest running the low level audio to a headphone amp in the room or run separate lines.

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PostPosted: Thu Jul 07, 2011 12:20 pm 
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Greetings! Glad to see a fellow Seattlite here.

For multicore cable, my first two recommendations would be Mogami or Canari. (Even though I'm using Mogami in mine, I love the Canari). I wish I could get it here locally.

The shield is run inside w/ the 24/2 (or 22/2) mic cable. Usually you have an actual drain wire along w/ additional copper wire or foil wrapping it to help shield it.

If budget is of concern, you can go with alternatives such as Belden, Gepco, etc. But if your savings are only marginal (like a hundred bucks or so, spend the money on the quality cable, you'll never regret it). It's when the savings are several hundred or even thousands where this should really be an option, in my opinion.

I prefer Neutrik connectors for XLR and many others. If you need a source for some at a great price, let me know, I'll send you a contact.

Most multipair cable come in the following pair quantities: 2, 4, 8, 12, 16, 24, and if you can find it, 32 and 48.

If the guitar cables are being amplified, run them separate. If it's only a line level, you'll be OK. Don't worry about PLENUM cable. You don't need it in the conduit, and it's very expensive.

The main issue with trying to mult or daisy chain your cables from room to room, A) a degradation in signal quality, B) an entrance for RF or other signals to enter your cable, C) you're running voltage! And there's more, but I can't think of them at the moment. Bottom line, avoid it if at all possible. Run your mic lines all as home runs. Period. I don't recommend it at all. However, what you could do to minimize, is use the one panel as a patch panel. Bring the short run to the same plate as the main runs, and create some short jumper cables and patch them in. You could do this, and as long as the connectors and shielding are done correctly, you can minimize any RF problems at that plate. Just food for thought. It's not as good as having a straight run, but if it's just a few connectors, you'll be fine.

Anyways, welcome to the forum!

Aaron


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PostPosted: Mon Nov 14, 2011 6:11 am 
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I know this thread is a bit old, but I'd like to give my two cents:

suntower wrote:
WHAT I WANT
1. I want to have XLR wall connectors and run balanced cable in the same conduit as the current twisted pair. One room will need 6 channels (drum room), one will need 4, and the others will need just 2.

2. And IF POSSIBLE, though this is NOT a deal-breaker, I'd like to have a stereo headphone connector in each room so I can have a monitor mix.

And IF I WERE ASKING FOR THE MOON, I'd also want one unbalanced (1/4") jack for plugging in a geetar, rather than having to drag around a DI box... But I have no idea how that would be possible without $$$$$.

3. And above all I need it to be CHEAP as possible. I don't want crap and I'm willing to do things properly, but this is a total 'budget' deal.

4. Oh... and on that note... to save money, I'm planning on 'multing' runs... ie. wiring the same connection in parallel in each room---since there will NEVER be a case where two people could accidentally plug into the same channel.

---JC


1. I say if you think you need 6 channels, put in 10. Always better to have those extra channels just in case, instead of the bare minimum you think you'll need. Also FWIW, don't try and pull past the cat5 cable, better to tie a string onto it and pull it out, put your new stuff on with it , then pull it back in.

2.You can run the headphone level on the same cable you use for the mics. It may not be the best way, but it will work. I've run my headphone amp into the 1/4" TRS returns of a snake and plugged headphones in at the box many times. I've also used adaptor cables and driven headphones with the line-level Left and Right Main balanced outputs of a console.

As for the guitar jack, you shouldn't run a high impedance un-balanced instrument line more than 20-25' or so. What you could do is mount a DI inside the wall and wire it to a 1/4" jack on a wall plate. Would be more expensive to do though, you'd need a DI at each wall plate.

3.West Penn 291 will do a great job for you. It's less than $100 for 1000' of wire. Doesn't have to be plenum either.

4.Home run every cable to a dedicated patchbay, then you can patch them wherever you need.

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PostPosted: Thu Jun 14, 2012 12:34 pm 
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Probably Totally Stupid Question: Does each 'pair' still have a 3rd wire or is there some other method for dealing with the ground?

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PostPosted: Fri Jun 15, 2012 4:16 am 
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Location: Cleveland, Ohio, USA
With balanced analog interconnects, the third wire (XLR pin #1) is not audio ground, it's the shield. It's normally connected to the chassis at both ends. But under some special conditions, the shield may not be connected at the receive end. Or maybe at the received end with a hybrid connection.

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PostPosted: Fri Jun 15, 2012 4:26 am 
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So each pair has a shield, but all the shields in a snake may be connected together or they may be connected individually .

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