🚀 go-pugleaf

You can order creative lab 's SB development kit. It contains
some C library functions for you to manipulate data with a 
sound file.

I have tried using that to do some signal processing stuff. Remember
SB VOC format is only 8 bit and the board itself doesn't have good
shielding for A/D input. So don 't be suprised if your data has a
high noise floor (about 45 - 50 dB). 

If you do it for fun, sound blaster is quite adequate. But you
are serious then I suggests using Turtle Beach or Pro Audio Spectrum 16.
SoundBlaster did come out with their 16 bit ASP board. But again, when
I check out their board, I don 't see they do a good job in shielding the
analog ground plane.
 
If you are doing signal processing stuff just for fun, I think SB is an
inexpensive solution. I have done something like sampling frequency 
conversion, time compression and expansion. It 's really fun.