Actually, a sound card does more processing than you think and requires quite a bit less CPU power than it does to run something like Popelscan. With a soundcard, you simply feed it a block of data and it handles the timing required to play it back. This is analogous to feeding a DAC an entire frame and then have it worry about proper timing, etc. With Popelscan, the CPU is responsible for timing and that is a big deal because at 30000 pps the timeslice is very small... much less than the resolution of a Windows timer. So, you have to loop and check constantly. That's very CPU intensive. But with the soundcard, you just fill a block and pass it on and then worry about the next one.
I don't know what all the Pangolin cards do but if it handles things like blanking delays and all then that is pretty cool and is definitely advanced. However, it wouldn't be too bad to do that in real time in software.
The only thing I don't like about soundcards is that you have to feed them a block and that results in latency. You also have to make sure that you feed it fast enough. I haven't worked much on my soundcard driver but I think I should change it so that a frame is a block and keep 3 or 4 on cue. That results in less than 1/2 delay for the most part.
Delay itself isn't too bad unless you are performing live. It can run into some problems I guess.
But, what is cool about WAV is that you can create a multichannel wav file with stereo music on channels 1&2 and the laser show on channels 3 through 8 or whatever. XYRGB + other. "Other" could be fed to a ADC to give you several TTL outputs. Or, you could simply dedicate the entire WAV to the lasershow.
You can then take your lasershow hardware and wav file and play it back on any computer using windows media player!!!!