Audiovisual question

[Badly Shaved Monkey]

Boys toys question...

At concerts you see lights that swivel and tilt in response to the music and also can change their beam colour continuously through the spectrum. Some also have masks that make shapes.

I have a hankering to have one of these at home to light up a room where we turn the music up LOUD.

I have no desire to acquire some big controller desk, but I have seen examples of these lights that are stand-alone so must have some sound or wired input to drive their movement and beam changes, but I don't know exactly what it is that I am looking for. In particular, how is the creation of this continuously variable colour output described because that is the feature I particularly want.

Are any of these thing available as amateur 'disco' products or are they only available as big, professional stage lights?

e.g. http://www.martin.com/productsubgroup/productsubgroup.asp?psg=movingheads

 

[GodMark2]

Are any of these thing available as amateur 'disco' products or are they only available as big, professional stage lights?

Ask and ye shall receive. These devices are often refered to as 'disco lightboxes'. Here is a controler yo can make yourself.

http://www.web-ee.com/Electronic-Projects/projects/disco_vu/index.shtml

The lights are just colored bulbs of whatever type you prefer. To make the 'cutout shapes' you'd need to add a lens or two, but if you just want to have lights pulse to the music, this should do it.

 

[kellyb]

Something like this is probably going to be as cheap, yet will arrive working, as you're going to get.
http://cgi.ebay.com/Technobeam-High...tcZphotoQQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I checked American DJ to see if there's any kind of new rip-off moving light out there, but I didn't see one. Technobeams are fairly small little guys that do everything you're talking about.
The shape making things are called "gobos" and you can order them individually. You can get pentagrams, stars...anything you could ever think of.
http://www.lighttrader.com/rosco_gobos.htm
You can even design your own and have it manufactured if you wanted. Don't know how expensive that is, though.


You can get control programs that'll run off your computer. I recommend Whole Hog software. It's really user friendly...it might only take you a day or two to figure out how to use it.
http://www.flyingpig.com/support/hog2/kb/pdfs/hogpc_c.pdf

You'll have to get some sort of DMX or XLR output converter to send signal from your computer to your light, as well.

In particular, how is the creation of this continuously variable colour output described because that is the feature I particularly want.

That'll be in your control program (which is basically an animation of those desks you see the lighting directors at concerts using...sort of like the ProTools of lighting). It's pretty self explanatory once you start messing around with it.

There's one bulb in the light, and a wheel of colored glass lenses that makes the beam of light change colors. There's another wheel that holds gobos, so you cal scroll between, say, stars and trees...make them rotate, etc.
So you program whatever you want into your Hog program, and then the light does what it's told when you press the play button with your curson on your computer screen.

 

[brodski]

in the Uk try maplins http://www.maplin.co.uk/search.aspx...=y&criteria=DISCO LIGHTING&doy=7m11&worldid=6

They're probably the best "home" supplier, but even places like Argos often sell "disco lighting". Just make sure that the model you buy can be powered by a domestic (13A) supply.

Eta- a lot of "disco" robotic lights have audio inputs or preset patterns, so a DMX controller is not absolutely essential. If you want to customize your lighting patterns you can pick up a cheep compact controller for about £80, but it's probably not worth it if you're only using one light.

If you want to "try before you buy" you could always look at hiring some equipment from somewhere like white-light http://www.whitelight.ltd.uk/hire/

 

[Badly Shaved Monkey]

Thanks for the various suggestions.

Can someone explain what is meant by 'dichroic' when refrring to these lights. Clearly the word itself means two colours, but what is the practical meaning.

 

[Serenity]

Thanks for the various suggestions.

Can someone explain what is meant by 'dichroic' when refrring to these lights. Clearly the word itself means two colours, but what is the practical meaning.

BSM, I don't know anything about that stuff, but here's something you might enjoy. I ran across this on YouTube last month and had saved the links.

 

[Topspy]

A dichroic is a piece of glass that has been vacuum coated with a film to pass a certain frequency of light (color,) although some are graduated to vary from one extreme to another - such as clear to deep red, etc. by stacking 3 rotating, graduated dichroic wheels in red, blue, and green (or yellow, magenta, and cyan) you can get any color you like. Another "greyscale" wheel OR an iris can controll intensity. A moving mirror can control direction (Intelibeams use this) and gobos (some lights have rotating gobos) are a cutout shape in a metal disk that project a pattern. Most fixtures are controlled by DMX 512 which lighting consoles understand, but are often able to be programed 'stand alone.'

 

[Topspy]

And some simpler, large fixtures just use "gels" which are colored films. Some have scrolls that roll the gels from side to side to change colors.

 

[Badly Shaved Monkey]

Thanks, Topspy.

Does that mean if the description of the product says "dichroic" then it can produce a continuously variable spectrum?

 

[richardm]

Can someone explain what is meant by 'dichroic' when refrring to these lights...what is the practical meaning.

I think that in this context it's not so much to do with colours as with a reflector design for dissipating heat to increase the life of the bulbs / avoid cooking things that they're pointed at. At any rate my car claims to have dichroic headlights and I hadn't noticed any exciting colours.

 

[brodski]

Thanks, Topspy.

Does that mean if the description of the product says "dichroic" then it can produce a continuously variable spectrum?

Not necessarily, as some lanterns use fixed dichroic filters to give just one colour. Almost all robotic lanterns you will buy these days will give you a pretty much fully variable spectrum. I would recommend dichroic systems over scrolling colour changers as they tend to last longer, especially at lower temperatures (I take it you're not looking at very powerful lanterns).
The best bet with these lights is to get yourself down to your local Maplins and ask for a demo, think about what effect you want to produce, what space you want to light, how you are going to hang the lantern and how you are going to power and control it. Also ask about how much replacement lamps ("bulbs") cost, and how readily available they are.

 

[Topspy]

Thanks, Topspy.

Does that mean if the description of the product says "dichroic" then it can produce a continuously variable spectrum?

As noted by others above, no. They are simply glass that has been coated, either in a variable way or a single color. In my showbiz days we used them to filter the beams of argon/krypton lasers to separate a particular color line for laser light shows.

 

[Topspy]

also, from this websit: http://www.inspirationfarm.com/GG/articles/article9.html

Dichroic glass is a high-tech spin-off of the space industry. "Dichroic" is defined as the property of having more than one color, especially when viewed from different angles or from transmitted to reflected light. Dichroic coated glass is produced by a process called "thin film physics" and is generally referred to as a color separator. It's normally used as an interference filter in scientific measuring or correcting applications. To get this effect, thin layers of metallic oxides, such as titanium, silicon, and magnesium are deposited upon the surface of the glass in a high temperature, vacuum furnace.
The glass to be coated is carefully cleaned, and fastened to a planetary arm in the top of the furnace chamber. The oxides are placed in a crucible on the bottom of the chamber. Air inside of the chamber is removed with a high vacuum-producing cyro-pump, and the chamber is heated to 300 °F. The metallic oxides are vaporized by an electron beam, and the rotating glass target is evenly coated with many thin layers. The resulting color is determined by the individual oxide compositions and the coatings sequence, totaling about 700 angstroms thick, (3 to 5 millionths of an inch). All of this is tightly controlled by a computer. Since the total thickness is so minute, the filter has very little mechanical integrity of its own and must be supported on a mechanically stable substrate. Glass is the ideal candidate for this substrate. It is transparent, has adequate rigidity, is stable, withstands relatively high temperatures, and is not affected by moisture, solvents or most acids.