garageCube

[LucasLucas]

The way I use madmapper (v3.7.11) with led strips is that I use a projector output to Spout, and the fixtures have that Spout input to sample from.

I have noticed that the opacity is not linear with the outputted DMX (seen in the DMX monitor) and that the Response parameter influences this 'dimmer curve'. Can someone explain me more about how this works? I have found that setting Response = 0 makes it sort of linear.

Is the non-linearity because the human eye doesn't perceive brightness in a linear way, so the Response parameter tries to visually correct for this? But why then (when fading from 100 to 0) is the outputted DMX already 0 before the opacity reaches 0 (or vice versa when fading from 0 to 100)? Shouldn't the two 'origin values' correspond (opacity 0 => DMX 0)?

[mad-matt]

You're correct. Response at 0% => linear, response at 25% => pow(value,2), response at 100% => pow(value,4)
That's because most led strips have a response curve around sqrt(input value), so response at 25% is what you need
But in recent MadMapper version we set response at 0% by default to make it linear.