Conventional Fixtures A look at the Altman Spectra Cube.

JChenault

Well-Known Member
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I am evaluating the Altman Spectra Cube for a houselight application. Thought it might be interesting to post my observations.

For my application I am planning to use just the 3000K white. What was provided was a RBGA unit.

The physical unit.
  • The unit is a 50 watt LED package. 24 LEDs in the head . An attractive compact package.
  • No fans at all ( a huge plus in my book)
  • There is an accessory holder that they use to put in various diffusion materials. The test unit came with a directional frost to somewhat emulate a PAR oval beam.
  • The unit has in and out connections for both data ( 5 pin ) and power ( powercon ) so you can daisy chain easily.
  • The yoke is the more or less standard for this class of fixture – IE a split yoke that you can separate if you want to simply place the unit on the floor – or you move them together to put a c-clamp on.
  • The fixture seems sturdy case is either steel or aluminum with what appears to be a powder coat. The hole in the yoke for the yoke bolt looks like it will easily take a 1/2 inch bolt.

There are a couple of problems (IMHO) with the packaging however.
  • Although the accessory slot looks like any old 6.25 inch accessory would work – it does not. You need an accessory sized for 5 5/8 inch to fit.
  • The method for setting modes / personalities and for setting the DMX values is the most arcane and unintuitive that I have ever seen. Read the instructions carefully and don’t lose them.


Dimming modes / personalities.
  • The unit will work in 8 or 16 bit modes.
  • You can choose to have an intensity channel, or just manipulate the colors directly.
  • You can choose to have ‘smoothing’ enabled.
IE there are eight modes.

8 bit mode / with intensity channel / no smoothing.
  • At the low end, the LED’s fire at a DMX level of about 16. When they fire they are at a very low intensity so there is n0 annoying pop on at the beginning.
  • There is a noticeable jitter with any fade slower than 2 or 3 seconds ( for full to off). I would not want to use these on ( say) a cyc with a slow fade or color change where that was all that was happening.
  • The response time from dark to full ( IE 0 to 10 in a 0 count) was immediate. IE you could use this as a strobe replacement if you are willing to program the cue into your console.

8 bit mode / intensity channel / smoothing on.
  • The jitter was slightly better. It was still there from about 10% to 35%, but not as strongly.
  • LEDs switched on at about 16 DMX.
  • The response time from dark to full is very fast – almost immediate. I could not use this as a strobe, but it would be fine for lightning.

In both 8 bit modes, the start of the fade down seemed a bit uneven. IE I would start the fade, and I did not see a change for about a tenth of a second, and then it jumped down and started moving.

16 bit mode – no smoothing.

  • Fade ups were very smooth just as you would expect. There was just a faint hint of a jitter – but I think that was only because I was looking for it.
  • The LED’s started firing earlier, around 54 ( from 0 to 65535 )
  • Fade down was also smooth, but after the fixture faded out, there was a flash. IE just before the LED went out, they flashed at a low, but noticeable level. In my test unit this occurred on a fade from full to our in 3 seconds or more.
  • The fade up on a 0 count seemed instantaneous to my eye. IE fast enough for a strobe.


16 bit mode – smoothing.
( this was the sweet spot for the unit)
  • The fades up and down were flat our smooth. I saw no jitter.
  • There was no flash on a slow fade.
  • A 0 count cue took about .3 seconds to come up. Not fast enough for a strobe effect.


In summary – a very nice unit if you are are willing to run in 16 bit mode with smoothing. I don’t know if the flash on slow fade outs is a defect in my test unit, or a problem with all of them – but for what I am doing it does not matter. The addressing issues, and the accessory size are going to be a real pain the rear end – but for an inexpensive unit (~746 USD street), it is (IMHO) quite good.
 

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  • There is a noticeable jitter with any fade slower than 2 or 3 seconds ( for full to off). I would not want to use these on ( say) a cyc with a slow fade or color change where that was all that was happening.

I've noticed that too with the Spectra cyc with other lights changing. Doesn't hesitate going to black in a zero count, but gets steppy in any sort of fade out.
 
I've noticed that too with the Spectra cyc with other lights changing. Doesn't hesitate going to black in a zero count, but gets steppy in any sort of fade out.

I'm guessing The spectra cyc uses the same electronics as the spectra cube. If so (and the spectra cyc has a 16 bit smooth mode, I would give that a try)
 

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