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4 replies

Splitting? Wireless? Long Cables? More than 1?

S studio42Member
I'm just trying to figure out some issues, come up with the best solutions. I am working more scenarios with VERY unfavorabe situations, such as no line of sight between my mix position and the stage. But the jobs are fun, I add a camera into my rig and the issueis resolved. I have another issue which involves me mixing FOH at quite literally the front of the house, making getting sepparation from the stage wash impossible, forcing me to mix on in-ear monitors.

Let's address the second scenario, mixing FOH from the front of the house as that situation is presenting me with lighting issues, which is where I am weak, because I am a sound production company who has to do lights.

So, there I am at the front of the house. Got my laptop, got MyDMX running on it with my DMX Operator as a standby(ready to be plugged into at a moment's notice). I have my 200-foot DMX cable that goes from my FOH position to the stage. Yes, I only need about 50 feet, but my links from stage to FOH are all based on 200-feet(my 56-channel audio whip, and two ruggedized Cat5's, as well as some additional Cat5's for baluns for other transports and some BNC 75-ohm cables for video). Getting DMX to the stage is NOT a problem. And other than not having sufficient short DMX cables, everything else is fine in regards to the stage. These cabling issues can be addressed later.

But the lighting is about to get more complicated out of necessity. I'm going to need to run a lot more lights for this event as what I have been doing is not sufficient. We tried, it sort of worked, but both myself and the promoter were in agreement that more is needed. Most of the issue is the stage area, which is easily addressed: more DMX cabling.

The event is a movie festival event, but they have contests, bands and live entertainment, which definately needs lighting. But I have to remain discrete, so no trusses. T-stands only or floor mounting, which I have no problems with.

But, here's my thoughts: I want to do some front lighting, mainly. 8 64 LED Pros(ADJ), plus a tree of 8 ADJ Par38's on a DP-DMX20L dimmer for more wash on each stage side, and for footlights/low wash, a pair of ADJ Color Fusions. For some penetration or accent, perhaps moving my Chauvent Intimidator Clors to either the back outer edges of the stage, or else using for more front spot/wash. Also, on top of my speaker stacks will be my Chauvet Q-Spot 150's.

At this point, I can't run more power for lights on the stage and be safe, but that's fine. What am I gonna run? 2 more trees of 8 par38's(1 per stage side?). So, I need my 2 follow spots, which are going to be located at the back corners of the stage, which MAY or MAY NOT be manned. I have to plan for manned operation being secondary. It's OK, they are DMX capable and they can be over-ridden. And thus the situation starts to get ugly.

Reading another thread here, it appears that restoration of power to a popped breaker can result in transient pulses of power sent down the DMX cable and possibly damaging the dongle, but the use of an Opto Branch 4 seems to rsolve this problem.

Another advantage of using the split is I can do a front of stage DMX run and a rear of stage DMX run, keeping cable mess minimized and on one side of the stage. I'm not seeing an issue there. In fact, this works in my favor.

But, what about the spots? I'm gonna be short on time, but I bet I could get the crew to run cabling from stage to the first spot, then chain to the second spot. Just seems a lot of effort to haul another split from the stage, DOWN the aisle between the outside section and the middle section(taped down of course), then across the rear to the second spot. However, wireless seems to be cost prohibitive and would require 1 transmitter and 2 receivers, which in turn burns that split port anyways. But if I go full wireless, then I need 3 receivers and well, mega ouch. So I think wireless isn't practical. I know I am allowed to run additional cabling while the movies are being shown, which gives me an addtional 100-120 minutes of "silent set-up" during the first segment to get the spots wired up for both power and signal. Are there any 2-way DMX splitters, even if not in a rack-mount format? I could still do my spotlight spit at FOH and avoid having to run yet another run up and down the stage. I can't find one at the moment.

My only limitation is that it needs to be an ADJ or Elation product that I'll consider. I like my Chauvet stuff, but I like my ADJ stuff better.

I bet I could get Accucable for a good price, then make my own cables like I did earlier this year. Making DMX Terminators is NOT an issue, I have 3 and will make more as necessary as I have like 90 properly spec'ed resistors.

My other concern involves a lot of my regular shows, where I can usually try to steal a circuit for the follow-spots, but those would be located close to FOH. I'd want to split those DMX signals right away, then send the main run up to the stage, to split again at the stagefor a front truss run, a front floor run, and a rear truss run. Worse case is I go MyDMX to spot 1, then out to spot 2, then out to the stage.

Any suggestions? Trying to save money, ensure reliability and making figure out any weak points. Money has to be spent. Cables have to be built. It's the nature of the beast. DMX will only be transported on Accucable DMX 3-wire cable, so that's one issue I don't have to worry about.
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S serraavaMember
Welcome to the oh so fun world of figuring out data paths. First, it is a shame that MyDMX doesn't have two universes, because problem solved easily right there. I often use 4 universes or more just to save on cabling to save time. Generally have a universe running every which way, with a splitter or two at the end.

So with that in mind, why not put a splitter back by yourself and then daisy chain another to the stage off of it? You then can have 4 universes of wireless plus all your hard wired stage stuff patched in no problem. If 4 channels isn't enough, add another split at FoH then. Keep in mind, you can daisy chain as many splits as you want/need. You could even come out of your link out in the FoH split, into a wireless DMX, then out into another split at the receiver.

Seems to me you will want to pick up a couple of splitters and a couple of wireless DMX systems at least. There isn't a show which I don't do anymore that doesn't at least have one splitter, generally 2 or more. For what they cost, how much cable runs they can save, how many problems they can solve, and the time they can save because of resolved issues and less cabling, splitters are worth their weight plus the Pelican 1500 I carry them in in gold.
S studio42Member
That's kind of what I was thinking.

Put an Opto-Branch 4 in my rack above my DMX Operator at FOH, move the DMX Operator down a tiny bit to sneak the cable through(for back-up). Run a split off MyDMX through the FOH splitter BACK to spots, then FRONT to stage. Another Opto-Branch 4 in the stagebox rack and do the stage splits from there.

Kind of pricy, but still less than wireless and makes the most sense. Makes logical sense.

Data paths isn't any big deal to me. Networking is a second language to me. So, I know FAR more about data than I care to admit.

One thing you mention that has me confused is universes. I understand what I universe is, so do correct me if I am wrong here. Do forgive me, I'm just a top end live sound engineer! As I have seen some high end lighting consoles, I've seen multiple DMX Outputs, each associating with its own universe, or so I assume. My possibly flawed understand is "1 cable, 1 universe", or at a minimum, 1 universe is a dedicated 512 DMX channels, which if you throw on another bit into the data stream, you can flag more universes to mux them onto that cable. So, using an Opto-Branch 4 is really simple a 1 universe signal repeater/splitter. I just don't see a "merge" or "additional data stream multiplexing" function capability in those boxes.

Going wireless: Depending on what my ADJ/Elation dealer can do for me, plus discussing with Jingles, it's not a matter of I can't afford it, it's just a matter of "gee, do I really want to spend it?" more than anything else. I hear what you are saying and I agree. I could run MyDMX to the transmitter, then put receivers at the stage and then a splitter, then another receiver at Spot 1 and 2(or just and chain to 2).

I think the two splitters is probably a good way to go. If I need to save money, put the split at FOH for now, then go do the stage normally. After all, my stage box only has one open slot in the rack anyhow! But the wireless in-ears do need to move elsewhere.... I do have the rack real estate at the moment to make this happen.

I've already got my audio figured out. I didn't want to bore you with that. A feed off my local for my in-ear. A set of stage side-fills for "Audience talk-back" mics to the "stage talent", 6 channels of performance monitors, then two sets of matrix feeds to other zones and rooms. Oh, and I forgot the monitor zone for the "MST3K emulation" zone! I can't be done, I still have sends open!

As far as my going with MyDMX over CompuLive, for what I need to do with lighting, for now, MyDMX is definately massive over-kill and I love it. But, should lighting really take off and I get a dedicated lighting guy, then I'll go CompuLive. My primary focus is sound, with lights added. Recording takes priority over lights, but lights takes priority over video.

Thanks for reading. I figured post to the Elation site instead of the ADJ site since I'm looking at Elation bits for addressing my latest puzzle I am trying to resolve. It's nice being able to stay within one larger company. Your idea was kind of how I was drifting. It seemed to make the most logical sense as far as split locations.
S serraavaMember
You are correct in that a splitter simply splits one DMX universe, or 512 channels. Splitter also isolates lines via transformers, so if there is a spike on one line, it won't hurt other fixtures off of other lines out of the split and/or the console. The splitter also acts like a signal amplifier, boosting DMX signal. DMX is generally good for a max of 32 instruments on one line, but splitter boosts this limit, making each line out of the splitter capable of a max of 32 units.

Universes are more or less just additional 512 channels of control. A lot of times however, I will use different universes to shorten cable runs even though I am not using all 512 channels on each. It is a simple matter of patching on the console to fix this. Higher end consoles, you can change the patch a million times, but all programs will remain unchanged. Reason for this is the console recognizes each light as whatever it is plus a number, so Power Spot 575 IE 1, Power Spot 575 IE 2, Design Spot 575 E 1, etc etc instead of just a bunch of channels.

Be careful though, some consoles have multiple outputs, but only one physical universe. The old Hog 500 for example has two DMX outputs on the back, but only 512 channels of addressing between the two. This is very rare now a days, but make sure you read carefully before assuming two outputs or more means more then one universe.
Last edited by serraava
S studio42Member
Well, I've got a show coming up in 10 days, but I don't have the time to come up with new hardware to facilitate this one, but this is more of a straight up concert/talent show(fixed band, multiple/rotating front/feature.)

I think my best option to save money is to get an Opto-Splitter for my FOH rig for now. Splits to front and back. Sufficient for now. Add to that plenty of fresh and new AccuCable 3-wire DMX cable and I'll get through my December 6 event. If I get into a budget crunch, I'll hold off on the opto-Splitter and just cheat and use my DMX Operator to control dimmer and color for the two spots only, while using MyDMX for the stage lighting, but still get plenty of MyDMX cabling. In fact, I may deal with the cabling tonight because I might need that for my next gig next weekend.

I do have a question that maybe ended up on another thread:
Is there really any difference between the opto-Branch 4 and the DMX-Branch 4 other than one is a floor unit and the other is a rack unit?(and cost)

Rack real-estage and what-not. It's not so much a matter of space, which I can do, but in regards to near future upgrades, which includes antenna distros, more in-ears(up to 6 more channels of in ear, 4 more channels if wireless mics, making 10 of each) and where is all this gonna fit in. Some will go in new racks, some won't. I'm also re-deploying racks to save money there, but they are almost all 12-space units.

I'm going to find out if it's cheaper to go with a 300-foot spool of Accucable and get ends or just buy 5 10-footers, 10 5-footers and 8 25-footers. Adventure time!

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