it is sound based? but it is already very "graphically", so it only sent the sound to multiple channels to 4 laser projectors? i use to tried sound card method but my m-audio410 only gives 0~24v, laser projectors requires -24~24V, that's the problem. anyway, do i need to modify the circuit in MOTU? if not then it is very good news! i hope Robert Henke can share some patch, just for the sound control...
It's highly unlikely that your m-audio outputs 0-24V. A standard audio signal oscillates from + to - (AC) and 24V would crazy loud for a line output. Around 5V would be more logical. My MOTU 828mk2 outputs +/-4.5V and my UltraLite mk3 +/-4.1V.
If your laser needs +/-24V then you will need an opamp to get the signal into that range. I recently worked with +/-5V lasers so it didn't need amplification.
Important is that the audio interface has to be able to output DC signals. Most filter out DC as a protection. MOTU is one of the exceptions that allow DC and thus can be used for analog control signals.
About 'sound control', the point that you seem to be missing is that you use audio DSP processes to generate control signals. Is it 'sound'? In a way, but any DSP signal only becomes sound when transduced by a speaker. Before that it's just digital numbers or analog voltages that can just as well be used to control the motion of a laser scanner or the intensity of a beam. That's what's happening here. It's perhaps more helpful to see it as LFO's. If you can draw shapes in an X/Y oscilloscope you can draw them with a laser.