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Thread: Laser growing up

  1. #11
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    I’ve been thinking of how I’d design a console since the golden age of Laserium. As Laserium matured the MARK VI console experienced a number of hacks, controls added here and there until the somewhat clean original design had a lot of exceptions. Learning those exceptions became kind of daunting!

    I wanted to get back to a clean minimum of 4 channel design, and eventually I realized that image rotation (4x4QMM), spirals (2x2QMM), and audio mod (2x2QMM) are image processing steps that can be thought of as separate from the image generation functions. Color mod and chopper maybe a part of image generation, but having different dynamic color mod for 4 different images would probably require presets. Still color mod enables and gain could be played live as could a bit of FM for one or all of the images.

    Joystick is easy, it gets summed in right before the output.

    I finally decided that the way to go was without all the hardwired pots and latching switches because they ultimately make it really hard to go from one setup to another. Still I wanted the core functionality to be dedicated to controls in specific places. (AND I want on the fly overrides.) If I want to turn down the gain on the “red” channel (2x2QMM)… (I know, but sue me.) I wanted that scanner’s gain to always be in the same place. Same for master gain and symmetry. Same for Joystick mode and enables. Same for fixed and variable rotation modes, enables, and sources.

    You may have noticed that this doesn’t really talk about imagery, just the processing of that imagery. Sure you can hook up a bank of quadrature oscillators for old times’ sake, The Radiator could go to another input. The number of multiplexed inputs per output channel is whatever you want. The user interface to configure the core image processing functions will involve illuminated “radio” buttons so the Laserist will know at a glance how it’s configured.

    Still, just a concept…
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  2. #12
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    Yes color control tut would be handy. Same for cloning. Another on assigning lfo to a function like say chop frequency.

  3. #13
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    Quote Originally Posted by swamidog View Post
    snip

    kecked, let me know if you want a color modulation tutorial
    Actually, I'd like a color modulation tutorial. I was playing around last night trying to figure color mod out, and as far as I could see there's no color mod gain control.

    Back in the bad old days before PCAOMs and RGB systems, color mod was done by sending the krypton laser's beam through a prism to fan out the colors that then bounced off a galvo and the diverging wedge of light passed through a second prism to make the beams parallel again. So, we had a ribbon of light made up of discrete red, yellow, green, and blue beams. These beams were picked off and sent to the scan pair for that color. Simple color mod was a sine wave signal that was sent to that galvo between the prisms. The result, as the color mod gain was turned up the beams whipped across the pickoffs at increasing amplitude. Color mod gain was a huge part of performing Laserium. Maybe there could be an "old school" mode?
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  4. #14
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    Thoughts / headings regarding what made the VIb era shows so good:

    Tempo vs. beat is part of a discussion including mimicry and narrative. laserist's previous lesson on missed cues is spot on.
    Mimicry means, for example, the diamond spirals specifically looking exactly how the wah effect on the guitar sounds. Mimicry in laser shows is mimicry of specific musical instruments or phrasing in the audio. Showing a vector picture of the subject of a song is not visual mimicry.

    Consistency of levels, or otherwise stated: how to not flash. A shape can do something interesting and be played live to music without changing it's size, color, position,or brightness. This is where the syncing 555's in the CYGN-B comes in so handy.

    As laserist mentioned, imagery and offsets. In much of the demos I see these days, it seem the importance of offsets used interestingly in choreography is often overlooked.

    Obviously lumia, slowly and quickly turning things, etc.

    Time line based choreography, including 351 as a timeline

    Examples of above principles from Walking On The Moon the KQO version (Not the moon graphic version), Follow Where I Am, Double Life, and Rocky Mountain Way:

    1) Follow Where I Am: a slow fade up of a really good live played lumia effect, after a while from which a dot sneaking amongst the nebulae tickles the viewers periphery of perception, and at an important juncture in the music, emerges as a small cycloid.

    2) Walking On The Moon: the big blue spiral with that gorgeous flyback just sits there, while the small green clothes peg skips and moonwalks slowly around the spiral, teasing the viewer to observe whether it is really staying between the lines the whole way down (it isn't.)

    The clothes peg becomes big and presents itself without the spiral in a way that illustrates the structure of the song.

    Just at the end when the bassy audio warble from actual Space Invaders arcade game preceding The Wait by the Pretenders comes in, the color mod sneaks in on this huge dim blue spiral. The audience comes back to see this again.

    3) Double Life: A big red CYGN-A analog lissajous with symmetries kicked over bursts on with the first note. It's slow and vibrant. The nodes crossing is played by the laserist riding oscillator frequency as an expression of the downbeats of the music.

    A big yellow duplicate comes and goes, and the slow exchange of sizes between red and yellow is played by the laserist.

    At a cue when the music conveys a sense of "getting deeper into", one axis of the third oscillator is brought up along with chop, so the viewer's eye is tricked into seeing an impossibly beautiful waving of straws. Spontaneous Wows and applause appears.

    4) Rocky Mountain Way: The signal strength bar effect (which I would like to know more about, and is one of those things that I'd love to bring back a working specimen of), appears big and red as the song opens. A blue duplicate appears and the interchange of red and blue on static offsets expresses the beat of the shuffle. This play of offsets involves the laserist moving the joystick only between the beats when the beam is off. This is a fun thing to do. As laserists, we should be wanting to do things like this.

    The blue and yellow danube hoops are introduced at a cue tied to a point of progression in the music. The use of the hoops first represents the chorus, then becomes the verse, and the plays on the music between the signal strength bar and the hoops are clever.

    The face sequence during the talk box part is a rare example of abstract laser image comedy, and subtly introduces the small green spiral as the nose.

    The culmination and fade out of the song brings all the previously introduced elements together in a little system where each thing plays it's role: the spiral bounces along the waves of the signal strength bar, and the hoops are like orbitals around the rock atom. Image gain and intensity diminish slowly over many seconds with the fade out of the song. This number was a masterpiece of abstract narrative in laser shows.
    Attached Thumbnails Attached Thumbnails multi_axis_control.jpg  


  5. #15
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    I meant The Farther Away I Am - Daryl Hall, not Follow Where I Am.

  6. #16
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    Quote Originally Posted by Greg View Post
    snip
    4) Rocky Mountain Way: The signal strength bar effect (which I would like to know more about, and is one of those things that I'd love to bring back a working specimen of)
    snip
    I believe you're referring to triangle audio mod. There were three types of audio mod:

    Direct Audio Mod
    Audio Modulated Fixed Cycloids
    Triangle Audio Mod

    The Audio Mod board had an audio compressor fed with the right and left channels and the output summed together. This was the AM signal and could be output to the one output axis and a phase shifted version sent to the other axis. There was a triangle wave oscillator that output to the card edge and was switched into the x axis at the multiplexer multiplier board. The AM signal was also routed through a high pass filter and a full wave rectifier to two 4QMMs to control the gain of the fixed cycloid signal. There was a spdt analog switch that selected between Direct and fixed cycloids.
    Last edited by laserist; 10-29-2020 at 14:11.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  7. #17
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    What's a 4QMM? this message is too short to post

  8. #18
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    Oh, I see it on the hybrid cardcage.

  9. #19
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    Quote Originally Posted by Greg View Post
    What's a 4QMM? this message is too short to post
    Sorry, 4QMM = four quadrant multiplier module. Either AD533 or AD532 chips. The AD532s were laser trimmed and much nicer to play with since there weren't three trim pots to screw with, pardon the pun.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  10. #20
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    Nice I love reading thi# stuff

    yes laser mimicry is a giant part of what I try to achieve. It’s all about relationships and making the connections between what you hear and what you see.

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