Learning! (Lighting)

[browna]

Hi, I've enjoyed lighting for a long time, though I am 17! I would like to learn more about the use of lighting! So if there's anything you would be willing to share regarding lighting, I would appreciate it!

 

- Can you control lighting live (via the desk), instead of pre-programmed, (for moving heads and generics) and still get the full enhanced show , lets say for a music gig?

- How do you control a row of moving heads independently, which are connected via daisy-chain?

 

 

Thanks!

[Ken Coker]

http://i47.photobucket.com/albums/f184/kclx1/LEC02_DMX.jpg

 

Can you guess now?

 

 

KC

 

(In the real world this is an animation...)

[twiggy]

- Can you control lighting live (via the desk), instead of pre-programmed, (for moving heads and generics) and still get the full enhanced show , lets say for a music gig?

Yes you can but how much you can do and how easy it is is dependent on what desk you are using to control them

 

- How do you control a row of moving heads independently, which are connected via daisy-chain?

There will be a set of dip switches or a digital display usually near where the DMX cables go in/ out and you need to assign different DMX channels to each mover.

 

I expect further replies will be asking for more information such as make and model of your desk and lights so if u provide this then it will be easier to help you out.

Also I'm sure most of this stuff has been covered before so try searching or the wiki.

[paulears]

Desks designed for busking - which we generally use to describe producing lighting on the fly, with little or no rehearsal is down to the desk, and how you programme it. When you have music events where to a large degree the lighting is a response to the music, it can be as simple as programming the building blocks, and then shoving a fader, or playing with flash/bump buttons. You could programme some chase style effects onto 5 flash buttons and 'play' them in time with the music - individually, or in multiples - look on it like playing the piano - you have the chord under your fingertips and arpegiate through the chord as the song progresses. Some desks let you put moving style effects on a single button/fader and one desk really good for this are the peaerls with the rollacue - you have a load of buttons and faders that work the 'looks'/'cues' - whatever you want to call them. Maybe all or most of them will be used duing the song, at the end of the song, you can advance the rolling cuelist and have a whole new set for the next song. Other desks, like the hogs have similar faders and buttons, but they are arranged in pages, so on mage one, you have the first song, page two has an entire new set for song 2. If you are using a Strand type theatre desk, then the sub-masters cxan do similar things, either running a 'state' directly, or by putting sequences onto a sub, can do similar things to the others.

 

The real skill comes in chosing what to put onto the buttons, selecting how they will work, and then playing the lights in at the proper time. Chases need to be timed properly, and really I guess I'm saying that busking is an artistic skill - pressing a go button isn't. Being able to busk a theatre show is pretty vital stuff, predicting what is about to happen and dealing with it sympathetically. So maybe your left hand is doing a flashy flashy chase, while your right is getting ready to bring in a blue wash under the flashing, then the flashes wash out, and you get ready to go red, with flashing amber and yellow, and a moving head sweep in the audience - most desks can do this kind of thing, others struggle a bit (as in every pc based control with mouse or tocuh pad operation!!! - sorry, had to get that in)

 

Not sure if this helps much?

[tokm]

A little off topic from the original request for help, but thought I'd post this question here as you'll see, it has to do with DMX & ML's!

 

General rule of thumb, no more than 32 DMX fixtures per line/universe, correct? What about if there's more than that, but the scenario includes a opto-isolated DMX splitter? Imagine.. I have my pearl running the show, line out into my DMX splitter and my 16x mac 500s (for example) and 18 LED Cans (cheap showtec 6 channel P64 things), some on one truss, some on another and a few on the floor, all with separate lines from the splitter to each position (i.e. a line for all the fixtures on the FOH truss, a line to all the fixtures on the back truss, etc). There's enough DMX channels on the universe to run all the fixtures.

 

Am I right in assuming I still have too many fixtures and that the rig will be very prone to problems? Or would it be OK as there's not 32 fixtures all in one chain... Well apart from on the cable in the LX foh loom, but surely the reason for the splitter/buffer is to help with this dilemma.

 

Both ways have merit IMO. So just thought I'd get some clarification seeing as I'm designing a festival rig right this moment where this could become an issue as I have only one DMX splitter. And the 2nd universe I'm going to run is going strait to the dimmers and the output of those dimmers is already planned to be sent somewhere else, after which, it'd be a pain (cable wise) to get to one of these positions where currently the fixtures are on universe one.

 

Thanks for the help & sorry if im straying close to something thats been covered before, just couldn't find anything exact to this/my situation.

 

Tom

[JimWebber]

Tom,

 

I'm not sure I follow your wording, but each line from your splitter will count as one "Universe" ie) Each line can then drive a maximum of 32 devices.

 

Don't forget that the splitter will count as one device on the universe it is connected to...

 

HTH

 

Jim

 

EDIT Spelling

[tokm]

Tom,

 

I'm not sure I follow your wording, but each line from your splitter will count as one "Universe" ie) Each line can then drive a maximum of 32 devices.

 

Don't forget that the splitter will count as one device on the universe it is connected to...

 

HTH

 

Jim

 

EDIT Spelling

Sorry if the wordings hard to understand, just trying to avoid getting answers like.. get another splitter or just run another line from your desk. When what I'm after is a clear answer, which Jims provided :D

 

Just to clarify, even with a splitter, you can't drive more than 32 fixtures from one universe from a desk, regardless of how the data is distro'd? If thats the case, its fine, I'll just have to see if I can get another splitter for the 2nd universe or work out an easy way to go from the last fixture on the 2nd universe to on stage fixtures.

 

Thanks again, what you've said is all I needed to know. Just something I've never had to deal with before. Usually never have this many fixtures spread over so many positions!

 

Tom

[J Pearce]

As far as my understanding goes you will be fine.

Essentially after each active stage you can have 32 devices. I believe its to limit current draw and voltage drop on the transmission line.

 

So you could have

 

desk -> 30 devices -> splitter

active out from splitter -> another 30 devices

another active out from splitter -> another 30 devices

 

etc

[paulears]

Moderation: fascinating as this is, gents, we've strayed a long way from the OPs question - and strayed into DMX territory that has been covered elsewhere. The OP said

How do you control a row of moving heads independently, which are connected via daisy-chain?

 

We seem to have evolved into talk of multiple, split DMX systems?

[tokm]

Moderation: fascinating as this is, gents, we've strayed a long way from the OPs question - and strayed into DMX territory that has been covered elsewhere. The OP said

How do you control a row of moving heads independently, which are connected via daisy-chain?

 

We seem to have evolved into talk of multiple, split DMX systems?

The topics called 'Learning', I've just learnt something. :D

 

The o/p asked about the linking of DMX fixtures, the scenario that I described was about the linking of DMX fixtures and how many you could link together on one line with the aid of a DMX splitting device.

 

Yes I admit its a little in between :D 'ness & being relevant, but just thought it was better to put it on here when all I was after was clarification, rather than start another topic, just to have facts pointed out to me, that I already know (which was all I could really find when I was searching the forum for an answer ,when I was after an opinion/answer on my specific problem and probably closed.

 

Oh and thanks J Pearce, how you put it was how I thought I understood it, but wasn't sure.

 

Tom

[Just Some Bloke]

- Can you control lighting live (via the desk), instead of pre-programmed, (for moving heads and generics) and still get the full enhanced show , lets say for a music gig?

 

Generics can be grouped together into subs or groups (e.g. all the blues together, all the reds together etc.) which make busking much easier. So song 1 may be a blue song, song 2 a red song and song 3 a magenta song (mix blues and reds together) for instance, though by mixing each at different levels you can get many shades of subtlety, especially when you start adding extra colours.

 

With MLs, palettes are your friend. On many desks you can make a build a colour palette where you press different buttons to get the different colours, so button 1 gives you blue, button 2 red, button 3 magenta etc. and this 1 button affects all your movers, if you want it to. Then you make a palette for 'beamshapes' (i.e. gobos and their focus, prism etc.) with button 1 doing dots, button 2 radial lines etc., and a palette for 'focus' (i.e. positions) then when busking you say "I'll have this colour, this beamshape and this position please" and it's all a matter of just pressing 3 buttons. You can do this with the intensity down so when you bring it back again they're already in the right settings. Some desks also let you save "all palettes" where the whole look is saved including the focus, colour and beamshape, so you just press 1 button to get the lot back.

 

All of this, of course, involves pre-programming the subs and palettes, but not the show itself.

 

If you want to programme nothing in advance, then for generics a 2-preset board is the way forward (or rather backwards as it's very old-fashioned technology that still works very well) where you have preset A doing the current look and you set up preset B for your next look then crossfade to it at the right time. For MLs this is harder, as getting positions right in particular can be quite fiddly and not something you'd want to do in real time.

 

Hope that helps.

[Don Allen]

Clarification of Daisy Chaining, because there are two kinds.

 

With DMX devices, they are connected in parallel, which is a balanced distribution system called RS484. RS485 is a two wire system that has the two wires fed from a non inverting amplifier into wire A , marked DMX+ in a lot of equipment manuals, and the second wire is fed through an inverting amplifier into wire B, marked DMX-. The reason for doing this is that as the signal travels down a long lead, electrical signals or noise will be coupled into the DMX signal. This undesired coupling of noise will normally corrupt the signal, especially if cheap mike cable is used as the shielding is not so good. However when the pair of wires get to the receiver, they are fed into a differential receiver that feeds the noise into an inverting and a non inverting input. The noise signal cancels out (almost). The DMX inverted signal is fed into the inverting input which by inverting it brings it back to a non inverted signal. The two DMX signal add together to be fed almost noise free into the receiver.

 

The DMX signal is fed into the receiver and passed onto the next device from the out or loop terminal, without any modifications, so the same signal is being received by every device on the same line.

 

Inside the device is a micro-controller which monitors the DMX signal and waits for data with a device address the same as it has been set to, by dip switches or input switches, usually with a display. The device will ignore the other DMX data on the line and only do what it is told to do. So providing every device of the DMX data line has their own separate address, they can do their own thing.

 

If you want two or more devices to do the same thing, then set them all to the same DMX address.

 

The DMX output devices, or RS485 transceivers, can supply enough current drive for 32 devices or receivers to be connected is parallel, or a daisy chain. Ideally a terminating resistor is at the end of the chain.

 

A DMX splitter or buffer has an input loading of 1 device and can feed 32 loads or devices.

 

The other type of Daisy Chain in used in disco lighting, where a balanced feed is used, but when DMX is fed into a device, the output of that device to others plugged into it's output may be DMX or control signals depending on how the devices are set up. This is a master slave setup. The user manual should explain if this function can occur and the screen printed instructions on the devices usually give a basic idea of how it is set up.

 

Hope this clarifies daisy chaining.

Don

[SilentShaddow]

Many people like to program and operate differently, I find it interesting to see how people like to arrange things and so on even when a desk lends itself to be so similar. I do think the lay out reflects your personality, even to the point where it would be odd if it didnt.

 

Im not sure what you mean by preprogrammed? but if your refering to preprogrammed lighting inculed in fixture for example sound to light etc?

[woody74]

Im not sure what you mean by preprogrammed?

Probably means just that: pre-programmed, as in not busking live. A "go" show.

 

-w