Taperssection.com
Gear / Technical Help => Cables => Topic started by: Patrick on December 13, 2011, 09:00:20 PM
-
I work for a media company that uses lots of cat-5 runs for video, digital audio, intercom, etc etc for live events. I want to be able to use a snake of bundled cat-5 cable, with a stagebox on one end, and a fanout at the other. With a build quality similar to a tour grade audio snake. My first thought was to use a multipin connector (db25) on the stagebox end, but I am not sure if I can send that many signals down a differently twisted style of cable. Does anyone have experience with this? I am interested in doing DIY as much as possible, but would be interested in pre-fabricated systems from a reputable company.
Also, sadly most of our gear is NOT wired for Neutrik ether-con connectors, so unfortunately we can't buy a system with those connectors installed.
-
Most Cat 5 is solid core wire and not so good for wrap unwrap needs that we require. I think there is also some other rfi issues but maybe someone else knows the score on that?
-
Energy Transformation Systems, Inc. (ETS) out in CA makes a 4 channel snake that uses Cat-5:
http://www.etslan.com/Audio.htm (http://www.etslan.com/Audio.htm)
I have never used their product so I cannot offer any opinion.
-
I had an internship with CAD Audio this past summer, and I had actually inquired about this as some of their podium mic products use CAT-5. The general consensus from the engineers there was CAT-5 worked pretty well for analog audio due to the twisted pair. I know they were sending balanced audio with some other digital signals no problem. Not sure if multiple channels of audio would be an issue though.
I would be careful in finding a good quality cable that was flexible and had good shielding though. That may up the cost...
-
There are a number of vendors that make 25 & 50 pair Cat 5 cables with Amphenol RJ21 connectors on the end. Then you can purchase Rj45 patch panels that will plug in to the amphenol connectors. They get used a lot in datacenters to provide quick and easy modular connections between server racks. Just double check your specs that Cat5 is adequate and that you do not need Cat5e or Cat6
http://www.panduit.com/Products/ProductOverviews/ProductSearch/index.htm?Ns=P_ItemSortOrder&lastNodeId=ss_prod_coppersolutions&N=5000001+3000032&Ne=5000008&recName=&sid=119A15E8F444
http://www.panduit.com/Products/ProductOverviews/ProductSearch/index.htm?Ns=P_ItemSortOrder&Ne=1&R=DP48584TV25Y&sid=119A15E8F444&lastNodeId=ss_prod_coppersolutions&N=5000001%203001560
-
Keep in mind there is a big difference between "will it work?" and "will it work as well as standard audio cables?". Yes, and No. And there is a huge gray area in between.
Cat 5 cable was designed for a different electrical environment with ON/OFF values of whole volts switching very rapidly... millions of times per second. Low Skew rate is more of a concern than noise rejection. As long as the noise isn't so bad that we start misreading ON/OFF values too often, ethernet users are happy.
We are sending mic level signals that are frequently millivolts, and we are much more fussy about picking up noise. In a traditional multichannel audio snake, each mic cable pair has an individual shield around it to prevent cross-talk with other pairs. If you using the Green pair, The Blue Pair, etc, of Cat 5 for individual channels I would expect some cross talk.
If you are able to "obtain" a ton of CAT5 from work and you want to try it, it should flow signal. If you put a ton of DIY work into it and it's noisy, I won't be surprised.
-
Keep in mind there is a big difference between "will it work?" and "will it work as well as standard audio cables?". Yes, and No. And there is a huge gray area in between.
Cat 5 cable was designed for a different electrical environment with ON/OFF values of whole volts switching very rapidly... millions of times per second. Low Skew rate is more of a concern than noise rejection. As long as the noise isn't so bad that we start misreading ON/OFF values too often, ethernet users are happy.
We are sending mic level signals that are frequently millivolts, and we are much more fussy about picking up noise. In a traditional multichannel audio snake, each mic cable pair has an individual shield around it to prevent cross-talk with other pairs. If you using the Green pair, The Blue Pair, etc, of Cat 5 for individual channels I would expect some cross talk.
If you are able to "obtain" a ton of CAT5 from work and you want to try it, it should flow signal. If you put a ton of DIY work into it and it's noisy, I won't be surprised.
Great point. The bottom line is if you are using the Cat 5 as a conduit for signal designed to be carried over Cat 5 you have a lot of options and you can be confident will function. But low level analog signals are very different from higher voltage digital traffic.
-
We aren't shoving analog audio down these snakes. We are using trannsmitter and receivers that are meant to be connected via cat 5 cable. I am just looking to make a high quality snake with stagebox for these cable runs as opposed to 4-5 "home runs" from FOH to Stage/truss.
-
HAVE Inc. can likely help you. They have good quality cable at good prices. I have purchased from them numerous times with good results.
-
Patrick. If you are not running an analog signal but in fact is a digital signal, then why not just skip wire completely and go with wireless?
-
3 quick reasons why I'd run cable.
Not all digital signals over twisted pair are Ethernet/Packet based.
Wifi has issues with RF interference. Without knowing the environment, it's hard to say it's a good idea.
We do corporate shows with large numbers of bored hackers/computer programmers. Not going to trust show-critical data to a wireless link.
-
A ton of the cat 5e cable we have at work is unshielded, so make sure you check that.
I'd say 85% of our stock is unshielded quad twst teflon.
-
Wow, I remember seeing Whirlwind cat-5 snakes years ago. Regarding wireless: definitely wouldn't do that. I wouldn't want to hope RFI bursts weren't getting into the line. Most arenas/stadiums are surrounded by microwave, cellular, UHF & VHF transmitters and repeaters. It's a wonder wireless mics and guitar packs work as well as they do without interference. Remember the scene in Spinal Tap where Nigel's wireless picks up the military plane transmissions? LOL! Stick with hardwired and you won't have to worry.
-
I'm actually just about try this out.
Using shielded data cable should allow for using it as a four-mic snake, and as mentioned above, the ETS guys make a very handy breakout box.
I know there's someone else on here doing this, but forget who..
From a specifications perspective, the theory is that data cable is made for very exact transmission of frequencies way above audio signals so those big fat slow audio freqs should be just fine.
The twisted pair concept has been around since at least the dawn of analog telephones to reject external noise (common mode rejection), and that certainly is well proven. Adding the shield of course helps with running your mic cables along electrical power sources and makes it possible to run four channels of phantom..
I think enough people are doing this in real life now that its gotta work pretty well.
Belden (who I happen to deal with through work) makes many types of cables for all sorts of applications, including industrial stuff made to flex continuously:
http://www.belden.com/techdatas/english/7938A.pdf
Some audio related info from Belden here:
http://www.sbe.org/sections/documents/UsingCat5e_Audio_Applications.pdf
Bottom line it should fun to check it out, and if I like it, it'll be a godsend for cheap, easy to manage, long mic cable runs :)
-
You can run anything you want over cat5, you just need a balun like the ones here:
http://muxlab.com/product?class=baluns
They're kind of pricey but they work fine. I have some for my house for routing audio/video where-ever I want.
Some other handy items are usb over cat5 converters like this:
http://www.iogear.com/product/GUCE51/
-
I made my own sub snakes using CAT6 SSTP cable. Each pair is individually shielded so no crosstalk problems. Be aware that there is solid copper and flexible (stranded) cable which is preferred.
You can use Ethercons or 9-pin DSUB connectors.