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    Heather Richards
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Steppy LEDs

I'm sure this has been covered several times already - I'm in a tech heavy day with no time or screen to hunt it down - apologies for the repeat!

I have some house and some rental Rgb LEDs in, and all of them are very steppy looking over longer cues at low intensity.  The designer has seen them behave much more smoothly - Im wondering if my console may be putting out dmx oddly, or if there is a trick besides part cues or discrete timing, or if that's just the way LEDs are.  The house ones are x-focus, rental colour blasts, I'm on an ion with software version 2, and to the best of my knowledge no output/priority settings have been changed since we got it in 2009, and we have net3.  Any advice appreciated!

  • Hi Heather,

    The first question I would ask is whether they are patched as 8bit or 16bit, and secondly whether the drivers for the LEDs can handle 16-bit. If you're using 8-bit drivers then you will always get steppy fades, particularly at low levels. If you have 16-bit capable drivers, then make sure they're patched as 16-bit (basically 2 addresses per colour). That means the fade can be much smoother.

    All the best

    Dan

  • If the Color Blasts are TRXs, putting them in 16b mode should clean that up.  If they're regular old Colorblasts, you're out of luck.  The 8-bit color blasts are always steppy at low levels on any console I've ever used them on.  You can mess around with DMX refresh rates, which might help with the X-focus units (I've never used those), but I've never found anything that helps.

  • If you have the headroom with your fixture's brightness, and no other options work for reducing the "steppiness", you can sometimes reduce the zipper noise by putting a neutral density gel on the fixtures. At the cost of output at the top end, it gets rid of some of the low-end drop down, which is accentuated when you have a lot of the same-type of fixtures dimming at the same time at the same rate...

    If you don't have easy access to ND, you might try fudging it a bit with colour correction, although I've never tried it myself.

  • in reply to JHarpur

    I also found you can play with the profile (curve).  If using the LED strip units with conventional fixtures, the bulb normally can be seen starting at around 7%.  So if you make a profile to start the curve at 7% for the LED I found it matches better.  We did this for our ColorBlaze 72 cyc strips.

  •   Thankyou all for these suggestions.  This time through we managed with parameter delays and part cues, however, it is top of my "spare time" list to try these before the next show requiring cueing comes in.  99.9% of the time I'm busking, so seeing LEDs come up to 10% over 30 seconds was a real shocker!  There also doesn't seem to be a profile for X-Focus blasts, so looking at a 16bit fixture patch looks to be a good experiment starting point.  Thx!

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