No signal processing done. I love my trusty old keyboard, and the output quality is decent. In this case the synth is done on the keyboard (not the laptop). Basic stereo line-in to the laptop's Realtek HDA chipset, recorded with Audacity, compressed at VBR2 with Lame.
I have the same keyboard. Great action for the price. It's built-in piano sounds are pretty nice but these days I've been using the MIDI out more and using it with the REASON Piano refill. It has a lot of nice pianos to chose from.
