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Thread: head-on beam shows... How do they do that?

  1. #1
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    Default head-on beam shows... How do they do that?

    We've all seen recorded laser beamshows where the beams fan out in a circle in all directions away from the scan head. Then various forms (walls of light, star-like beam paterns, etc) move back and fourth, up and down, all in time to the driving beat. It looks very cool...

    Now, how the hell are you going to do such a show while still adhering to the CDRH rules that specify all beams must be 3 meters off the floor at the highest point in the audience, and must have a horizontal separation of 2 meters on either side of where the audience can stand (or sit).

    This means that there is a central cone (well, a rectangle actually) where you MUST NOT have any beams. Yet in order to accomplish the effects listed above, the beams *must* swoop through this audience area.

    I thought audience scanning was not permitted? (Or, more correctly, that the calculations required to prove you're under the MPE limit for every point of every frame become so tedious and involved that no one is willing to go to the trouble to try and get an audience scanning show certified, especially with the various interpretations of what, exactly, constitutes the MPE...)

    So what gives? Are all these shows we've seen on video actually outlaw shows? Or maybe just shows that are only open to private groups, where the CDRH has no juristiction? (They have no juristiction if there is no "commerce" involved, either directly or indirectly, with the presentation of the show.)

    This has me confused, because one of the wining shows in an ILDA competition a few years ago seemed to violate the rules for audience scanning. And it seems odd that someone would go to the trouble to create such a detailed show and submit it for the competition knowing that it could not be used commercially.

    So, what is the missing piece of this puzzle?

  2. #2
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    Default

    Most of those videos you are seeing are over around Europe. Lasers are real big there Others are just demos.

    In the US they made the regulations "impossible" to bypass. 5mW max and 250mS to detect a standing beam in the audience and shut down the laser.

    The US is bad about protecting dumb people.

    Anywho: US laserists not used to hearing something is impossible decided something needed to be done. The 5mW max rule can be adhered to by greatly increasing the beam diameter. The 250mS stop time was a bit harder.

    Basically medialas made a system called "cat-safe" which allowed you to connect their microamps up to it and shut down a dpss rail in about 100mS upon detection. (I cant remember if its a dpss rail or some sort of violently quick shutter system, either way: impressive tech.)

    There are a few other requirements i have forgotten but they are equally insane.

    So: its doable in the US, just real real lame. Some lasers need to be expanded to the size of spot lights to pass the regulations.

    I personally think the threat of going blind and lawsuits are adequate punishment, but the US Govt. has taken it upon themselves to protect you from yourself.

  3. #3
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    Default

    To add to what spec mentioned. There's also specialized scanners with
    high inertia mirrors where the driver is more of a "suggestion" specifically
    designed for audience scanning.

    Another note is that most of of the audience scanning laser shows in
    Europe are still actually breaking or at the very least bending the legal limits.
    I've personally run into several clubs in the US which continues to happily nail
    unsuspecting club-kids with Class IV static laser beams!

  4. #4
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    Default

    yeah, lasers are really booming here, mostly seen at large dance aprties. Very cool full color shows etc

    Take a look at the pictures of this party for example: Qlimax

  5. #5
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    Hotlinked from above site:


    Thats absolutely beautiful...

  6. #6
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    no THIS is


  7. #7
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    Quote Originally Posted by liteglow
    no THIS is

    lol!

  8. #8
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    Default

    I am only getting a logo. Or is that the joke? :?

  9. #9
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    Quote Originally Posted by ElGordito
    I am only getting a logo. Or is that the joke? :?
    nope, that is because hot linking isn't allowed. Just copy the address of the picture, past it in a new browser window. Hit enter... then you will see the same logo saying hot linking isnt allowed. Then hit [ctrl] and [F5] both at the same time and you should be able to see the pictures

  10. #10
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    Quote Originally Posted by addictive
    Quote Originally Posted by ElGordito
    I am only getting a logo. Or is that the joke? :?
    nope, that is because hot linking isn't allowed. Just copy the address of the picture, past it in a new browser window. Hit enter... then you will see the same logo saying hot linking isnt allowed. Then hit [ctrl] and [F5] both at the same time and you should be able to see the pictures
    and when you have done that, you can se the pic here

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