| Author | Message | ||
| byoung
Senior Member Username: byoung Post Number: 1015 Registered: 12-2004 |
So. I'm attempting to wire up our church sound system. Specifically, I'm going to wire all the microphone jacks in floor boxes. Previously, we had a snake (aka multi-core) which worked fine, but for the distances we're talking about, and the fact that we're going to be re-wiring the whole platform anyways, I'm hoping to just hard-wire the whole thing. Wires from the box in the platform to the sound booth. I have found the jacks on line, and feel confident that buying a good brand (switchcraft or neutrik, both of which Alembic uses) will save hassles. However, I'm at a loss as to what wire to use. This is going to be a permanent installation, and I'd need about 1000 or so feet. Does anyone have suggestions? Would I be totally insane to use cat 5 wiring, which is easy to acquire and has good noise rejection? Will phantom power be a problem in this case? Just for reference, I'm looking for something that works, and will last, and won't give me headaches. I don't really care about "audiophile" items like gold plating or stuff that costs $100 a foot. Bradley | ||
| dfung60
Advanced Member Username: dfung60 Post Number: 320 Registered: 5-2002 |
You don't want to use Cat5 - it's cheap and common twisted pair for data transmission, but it's unshielded which won't work for you. It's also the wrong impedance which will cause problems. You need to get real microphone cable which is twisted pair with 100% shielding. The well-known names would be things like Belden or Mogami. I just glanced at Markertek.com and it looks like you'd be looking at $250-$600 for 1000 feet. There are special systems that run audio or video over regular cat 5 wiring. They are intended for use in applications where you want to get point to point with a few signals and running coax or audio cable would be prohibitive in price. These systems use special transformers on each end to process and recover the signal but the endpoints would be expensive for a system like you're building. David Fung | ||
| byoung
Senior Member Username: byoung Post Number: 1016 Registered: 12-2004 |
Thanks David. Would something like the following: https://www.cablesforless.com/index.asp?PageAction=VIEWPROD&ProdID=15079 Work? My big concern is that it isn't 100% shielded, only "copper wound, 95%" shielded. Does the gauge matter much? 20 vs. 22 gauge? I can get 22 gauge Belden cable which looks correct for my application here: http://www.newark.com/05F1851/cable-wire-accessories/product.us0?sku=BELDEN-1266A-0101000 For $158 per 1000 ft. Is that suitable? Do I need a higher (lower numbered) gauge? I'll have a max run of approx 150 ft., and will be running some "line level" (amplifier returns) stuff, hopefully over the same type of cable. | ||
| bkbass
Intermediate Member Username: bkbass Post Number: 166 Registered: 11-2003 |
I've wired up my Church with Canare StarQuad (4wire + braided ground). I used HAVE INC.to purchase the wire from as they had the best Prices at the time. I got hip to Canare from an old Rick Turner article in Guitar Player Magazine. Nuff Said? I find it to be quieter than Mogami and less microphonic as well. | ||
| dfung60
Advanced Member Username: dfung60 Post Number: 322 Registered: 5-2002 |
byoung - The deal with shielding percentage is related to whether you're going to be handling the cable or not. With the Belden cables for permanent installation, they use an aluminum shielding foil that is wrapped around the signal pair. Its 100% shielding (which is good), but if you use that kind of cable for a stage mic, then bending or stepping on the cable can fracture the foil and things go downhill quickly from there. For cables that you handle, you normally use braided copper for that which can take the flexing with no hassles, but they typically are not 100% shielding. If you remember the discussion here a while back about Alembic unearthing an old cache of blue Alembic Supercables, that blue cable was the original high-use version of Beldfoil for unbalanced instrument cables, but I think it just didn't hold up well over time compared to plain old braided cable. I think the Belden that you mentioned was OK for a permanent installation like this. I looked around and I had some Belden 9451 cable which is pretty similar. It has the foil shield, but there's also a drain wire that runs along the inside as well. It's much easier to connect the drain wire up to the termination point than to try to do something with the foil, so this might be a little better (probably also a little more expensive). This is thinner stuff than what you would use for a stage mic, no rubber coating. Belden has options of solid vs. stranded wire in most configurations as well. I think solid is easier to solder/terminate, but you don't want to use it unless the wire is all securely fastened down to prevent it from fracturing. The Canare cable the bkbass is also excellent stuff. It may be different now, but it used to be more expensive than the basic Mogami cable. David Fung | ||
| kmh364
Senior Member Username: kmh364 Post Number: 2245 Registered: 9-2003 |
As an Electrical Inspector (Code Official), I'd offer one caveat: Ck with your local Building Dept. BEFORE you install your cables. If you're doing a permanent install, and area(s) you're running your cables in can be classified as "Plenum Spaces", then you may be required to install listed "plenum-rated" cables in order to be compliant with the local fire Code(s) in effect in that jurisdication. Just a head's up, Kevin | ||
| dfung60
Advanced Member Username: dfung60 Post Number: 324 Registered: 5-2002 |
Kevin's point is really important - the reason for plenum rated cabling is to prevent your cables from spreading fire and toxic gases between areas and levels of your structure. You see this commonly with ethernet cabling in buildings - when it passes from floor to floor, you need to use special cable and special construction. I believe this is particularly important for audio cable as the foamy dielectric in some regular coax (you have shielded twisted pair, not coax, so this is less of an issue for you) is quite flammable. You almost always have to deal with plenum issues when passing between levels of a building. Safety comes first, but the bad part is the plenum-rated cable can cost many times what the regular horizontal run stuff costs (for ethernet cable, it's often 3x). If I got any of the facts wrong here, please correct me! David Fung | ||
| kmh364
Senior Member Username: kmh364 Post Number: 2246 Registered: 9-2003 |
Exactly. It's an issue in Residential construction as well. If a builder does permanent in-wall cabling (like home theatre, etc.), the cables all have to be listed "plenum rated" stuff. In a commercial install, especially, a "place of public gathering" (i.e., like a church), you have to be very careful. Personally, I'd contact the local Building Dept. and speak to one of the Code Officials in charge. What's the worst that could happen: you have to pay for a alteration Permit and be subject to inspection? I'd rather have everything documented in case there's ever an issue (i.e., fire). Loss of life not withstanding, you don't want to have insult added to injury if/when the insurance company denies the claim because of illegal mods. Just my two cents. FWIW, I ALWAYS have to use plenum rated and/or low-smoke/low-toxicity stuff as I do only capital construction at large public facilities (currently at EWR airport) for a public agency. It's in our boiler-plate specification as it's required by Code and required by our Risk Mgt. Division (we're self-insured with a BIG Lloyds of London "umbrella"). | ||
| keith_h
Senior Member Username: keith_h Post Number: 1005 Registered: 2-2005 |
One other item to check is whether the cables have to be in conduit since it is a permanent commercial installation. Even though they are low voltage and current some localities require anything that carries a voltage to be in conduits. Keith | ||
| byoung
Senior Member Username: byoung Post Number: 1017 Registered: 12-2004 |
My father in law is a licensed and bonded electrical contractor, and will be doing the installation. I'm quite certain that everything will be dress-right-dress with regards to plenum rating, etc.; I understand your concern. Bradley |
