Anyone setup a DMX stage lighting rig?

[mikkydoos]

Need to know the exact in's and out's of setting up a permanent DMX stage lighting rig with all moveable heads.

 

Got a fairly good idea of what to do and have a sparky to fit it all in.

 

Already put in a 1000w PA system.

 

 

Wanted to hear about any of your experiences.

 

 

Cheers,

 

Mikky

[gazlee]

Hi Mikky, I've setup a few, they basically involve creating a daisy-chained network of fixtures.

 

Each fixture (light) will have a DMX in and out on it and will need to be assigned a unique starting channel using DIP switches on the unit, or newer kit usually has a little LCD to set the channels.

 

If the lights have only one function such as a simple dimming flood or fresnel, you'll just need 1 channel per fixture, so flood 1 can be on channel 1 and flood 2 can be on channel 2.

 

If the lights have multiple functions (such as the moving heads you have), you'll need a few channels per fixture, for example moving head 1 may start at channel 1, but will occupy a channel for every controllable feature, so lets say MH1 will have a channel for dimming, a channel for pan and another for tilt, this means the next MH in the chain will need to start at channel 4 to avoid interfering with the first MH.

 

Control desks usually have one fader per channel (unless you're using a computer based control system), so using the moving heads as an example again, fader 1 will control MH1's dimming, 2 will be MH1's pan, 3 will be MH1's tilt and channel 4 will be MH2's dimming and so on...

One DMX universe (think subnets) has 512 channels available to use.

 

Stuff to think about (that's caught me out) includes -

 

DMX polarity - Some manufacturers have adopted a reversed polarity implementation of the DMX connector, you should be able to overcome this with some adapters (i'm pretty sure I've seen them around)

DMX cabling - Usually you can get away with using XLR microphone leads to connect 3 pin fixtures together, however for permanent installations I'd suggest getting proper shielded DMX cable, to prevent electromagnetic interference.

Connectors - There's two types of DMX connectors, one is 5-pin XLR and the other is 3-pin XLR, while the 5-pin version is the supposed to be the standard, lots of kit uses the 3-pin version, again you can easily convert them with pigtails/adapters.

Massive cable runs - I'm not sure what the actual spec states about the length of cable runs, but if you have long cable runs, the network can suffer from signal loss which introduces anomalies like intermittent control and random fixture behaviour.

Termination - At the end of the chain, you should use DMX terminator plugs, they stop the data from bouncing back into the network and making weird things happen, they can be bought or made very cheaply.

 

I hope that makes sense, if theres anything else you need to know I'll try and answer as best I can!

Gary

[Willott]

You can use CAT5E cabling in place of DMX for your long runs, just be careful to ensure you have decent termination (suggested IDC/punchdown). Cable characteristics meet DMX requirements, and it's a heck of a lot cheaper than DMX.

 

Main thing is to plan where you want fixtures, and your DMX boxes so that you can ensure expandability, but also ensure you can easily check for breaks in the chain.

 

Will

[mikkydoos]

Thanks guys for your tips.

 

I'm pretty sussed on the configuration but this is going into a medium sized gym so I reckon the DMX cable runs are a bit over 30m.

 

Also lamp placement.....

 

Ceiling is approx 10m (?) with RSJ's supporting the roof. Stage is centre of the long side of a rectangle. Any suggestions on lamp placement?

 

I'll be buying 3 x moving head spots and 1 x multihead moving spots (4 lamps on one unit) for the centre of the roof.

 

Wheres the best place to put the stage lamps? Above the stage? Back wall? Centre of ceiling?

 

Lamps can't be fitted to the wall because obviously they move!

 

Appreciate the help

 

Cheers.

[Chris_Cook]

The dmx cable runs should be fine, as long as they are well made. You can have up to 30 devices on a correctly run cable. I've used 100m dmx cables before without problems. If you have dodgy cables, or use stuff that isn't up to the dmx specification, then you can get all sorts of problems, even with short runs.

 

You might be best off talking to a local stage lighting company or a theater to look at the positions of the lights. It depends on both the shape of the venue and what you want to use them for.

 

You will want some light from the front (where the audience is), one each side. These need to be high enough up/far enough forward that the light doesn't shine in the acts eyes, but not so far as to cast shadows on their faces from their noses. You will also want some light from behind and from each side. This makes people on stand out on stage, and not just blend into the background. Take a look at some other venues that do similar events, and see what they have. If you can talk to a lighting engineer and get them to show you how all the lights work together, it will help you do a much better job of your own install.

 

Are these moving lights complementing a set of generic theater spot lights, or are you using them instead of spots? If the movers are complementing, then they are best above the stage, either behind the act, or to the sides. Directly above isn't that much use. Will you have anything other than the 3 movers and the 1 multihead?

[mikkydoos]

I havent actually purchased anything yet. The multihead is really for effects and disco lighting.

 

The singles are to light the stage. Occasionally they change the orientation of the room, so the stage is on one of the shorter walls - hence the moveable heads.

 

Cant do behind as the stage is only stage blocks up against the wall and about 3 feet high at most.

 

I reckon one centre stage two left and right of the stage, but put them fairly far back in the room as to avoid shadowing.

 

????

[jamesreedersmith]

Please watch out for the amount of maintenance moving heads need - i had some in a school hall and then needed de-rigging and cleaning every three months because they are dust magnets - you will be better to but some parcans/fresenls/profiles and dimmer packs and then hire MH when you need them, they are a great expense to buy and maintain.

[mikkydoos]

Heres the setup. Yellow box is the stage.

 

Dimensions are approx:

 

Length - 20m

 

Width - 10m

 

Pics:

 

[Andrew_C]

What James says...

 

It is quite likely that everyone will go "WOW! when they first see it, but this time next year when two lanterns have shutters stuck, there is no money for spare lamps, and the fans need cleaning but no one knows how, your name will be mud.

 

Use CAT5 for fixed wiring only, use proper DMX cable for flying leads. Very few fittings will now have reversed pins 2&3, but lots of cheap kit does have 3 pin XLR on it.

[mikkydoos]

Well I know Im going the LED route for sure

[sdc]

CPC have some great LED par cans - three-channel DMX (R,G,B), at less than £30 each they're fantastic value. Only thing is they're not as powerful as normal par cans, so they probably need to be a little nearer the stage. Sat on the stage edge, pointing upwards at actors or to light a scene, they're great.

[jamesreedersmith]

LED fixtures still have the same problem - what mainly happens with moving heads is the joints become dirty and dusty, this then causes them not to respond as well and eventually jam.

 

The bearings and joints need as much maintenance as the optics.

[jamesreedersmith]

LED fixtures still have the same problem - what mainly happens with moving heads is the joints become dirty and dusty, this then causes them not to respond as well and eventually jam.

 

The bearings and joints need as much maintenance as the optics.

[Chris_Cook]

Good point about the maintenance. Three months is a bit excessive, unless your in a really dusty place. Movers are much more flexible if you are restricted on using a ladder. Movers do take longer to program, but you have a good selection of colours and gobos (Shapes) available. Its all a compromise. All these lamps will need regular lamp changes every couple of years. That will depend on usage obviously. Taking a larger head down can be a bit of a challenge and requires a certain amount of competence to put it back up safely. the 250 watt heads are quite heavy. Bigger ones will be a 2 person job.

 

If you are going to have the stage in different places, then I would go for 4 single heads, forget the multi head and maybe get some cheaper disco lights if you need them. Martin make some nice stuff like the manias. If you run them of a dmx switch pack (not a dimmer!). then you could have quite a good disco rig.

 

I would push the lights out to the sides if you aren't using proper back lighting. If you have 4 of them, then maybe set them up in a square, two close to the stage, and two far away. I think that would give you best coverage of both the stage areas. Having one in the center isn't necessary with this set up, and if anything will just annoy anyone on stage (the light will be more in their eyes).

 

Depending on which heads you are going for, it is worth comparing the cost of traditional lighting. You might be able to get more fixtures that can be left focused in a useful way. 4 movers is still quite limited. If they arn't going to be used with other lights, then you won't be able to do much interesting with them.

 

I think you may also want to factor in some training on this project too. Whilst its not a problem to teach your self the desk, there is an art to using the equipment well and safely. The end result will be much better and much more professional.

 

Edit: I hadn't seen the photos or the posts after that when I wrote that. I think to get a good result you need to get the pros in.

Edited February 28, 2012 by Chris_Cook

[Oaktech]

when i used to look after a big club, with about a hundred moving lights, the maintenance was like painting the forth bridge, honest to god i was there every couple of days. If you only have a a few lights, that you use 2 or 3 times a year I would expect a decent offering from pearl river, martin, robe etc to last at least a year without maintenance.

 

For the love of god, don't buy led moving heads to hang up, the light won't reach the floor. But for use on the floor, LED cans are pretty handy.

[mikkydoos]

I think to get a good result you need to get the pros in.

I did. Best I could get for 5 lamps, a desk, and the install, WITHOUT them doing the electrics, was £6000.

 

Ive seen the PARs on CPC for say £40. God knows how they got it up to £6000.

 

I didnt realise that moving heads were so niggly.

[Chris_Cook]

Did you get a breakdown of the individual costs for that quote? It doesn't sound completely unreasonable for a good job.

 

There are two routes to go with lighting, the cheap way, which will last 3-5 years and be rubbish. bulbs will blow, it won't really every do what you want, and it will look cheap. As someone else said, after a while it won't get used anymore, and will either have to be replaced or written off. Then there is the expensive proper way that gives you a good result.

 

The room looks quite tall relative to its width and length. I think having the lights at the roof height won't give a good result. A parcan at that height will light a good chunk of the hall, which might not be what you want. I suspect they might have included some rigging to drop the lamps down a meter or two.

 

They probably have included a higher end desk, and profiles and fresnels which are much more expensive than parcans (more like £200+ each). Dimmers are expensive too. Given that dimmers will probably be left on, and use lots of current, you don't want a cheap and nasty one. Most of these are designed for small temporary jobs, and only to be used for short periods of time.

 

I would really recommend not buying the very cheap lighting unless you have quite a bit of experience of using this sort of thing. Most of it really isn't worth the time. Cheap desks are horrible to use. Cheap lights tend to be quite dim. Cheap movers will be missing features like remote control of the focus and the beam size, which will effect the end result.

 

When doing lighting, its more important to think about what you are trying to achieve than what equipment your are buying. When you pay for the install, you are also paying for lots of experience that they have working in different venues and for different clients.

[iSteve]

Please don't buy moving heads, particularly on a budget to do your front light. It's likely that the beam angle on them will be too narrow to sufficiently do your front wash. Again, it's unlikely they will have framing shutters so you will have spill on to your proscenium, no focus or frost, and if the colour wheel doesn't have colour correction everyone will look very cold from the discharge lamp (forgive me, I've just read some of this further up, so it's repetition). Cheap low end disco movers will also be loud. Used ETC Source 4 profiles are high quality and reasonably priced and will give you a more natural, controllable light for front light. Of course, if your school is minted and we are talking about using Martin TW1, or VL1000s, go for it!

 

For front light you want some good profiles, or fresnels with barndoors. Have a look here Used Lighting & Ex-Hire Stage Lighting Equipment Sales | usedlighting.co.uk under Conventional Fixtures. Most schools will find the Strand Quartet or CCT Minuette range suitable. I've used this company for work and out of school purchases. There's nothing really to go wrong in a 2nd hand fresnel, so it makes financial sense.

 

Dimming wise, Zero 88 Chillis are good reliable dimmers, available as hard wired. Or on the used route, Strand ACT6 or anything by Pulsar is rock solid.

 

You will need a structural engineer to assess the load bearing of your roof. DO NOT just hang stuff off girders and hope for the best. Your LX bars (which you will also need - else where is your power and data coming from?) will need load testing and certification.

 

If this lighting system is to be of any real use (eg school plays) you need a good basic desk, either memory or 2 preset. Do not buy disco junk for this. If you do go for moving heads, you need a desk capable of LTP/HTP moving light control.

 

CPC LED PARs at £40 will be washed out by an overcast day. These sort of things are designed for eye-candy at discos. They aren't designed for 'proper' lighting. Usually the dimming curve on them is horrendous. The beam angle will be tight, and you won't be able to mix a good enough white for basic work. LED suitable for 'proper' lighting will cost more than several 2nd hand convensionals.

 

Whatever you do, make sure you budget enough for that odd extension cable you might need, replacement lamps, tapes etc.

 

There is a lot to think about here, and a risk of money being wasted if it's not thought about properly by experienced people.

[mikkydoos]

OK. Thanks for great replies guys.

 

Budget is £5000 minus a short throw projector and cage + fitting.

 

Any recommendations on spec / positioning ?? -- Got to be DMX and preferably RGB lamps!

 

Have I got enough ??

[rdk]

I concur with the comments above, but can I add you might need to ensure the lighting and sound systems are wired on completely different circuits. This is obviuosly quite expensive, but if not done you risk a continual hum through the sound system, varying when you adjust the lights through your dimmer.

[mikkydoos]

Youre right RDK. I'm a musician. Earth loop hums are terrible!

[Andrew_C]

But wiring from separate circuits will NOT cure earth loops. Proper wiring of the sound system is the only cure and prevention is always better than cure!

[mikkydoos]

Yep. Balance everything.

 

Big thanks to all you guys for your helpful comments. I think I've got a pretty good idea about what to do.

Managed to get a good price on a pro installation with maintenence ; )

 

Mikky ; )