i have done a bit of analysis on this. It turns out with WASPI there is a different issue coming into play, where for a reason i dont understand yet, the same data is being returned 3 times in a row. So that would explain the slowness that people report if they use WASPI.
DirectSound doesnt have that problem.
For the discrepency between hearing and seeing, according to the bass documentation the data should represent whats being header i guess that means its when the data has been sent by the bass library to the output device.
So can you confirm the delay you see is the visualiser is ahead of what you hear or is behind what you hear?
The waveform is probably a different issue but i havent looked at that yet