This sound is strongly inspired by (but not meant to sound exactly like) a wonderful video by Ed Zuccollo, which you can see below.

Put good reverb and delay on it, carefully use the filter cutoff, and you’re in heaven.

 

Listen: (This is really just an example, and not at all comparable to the performance shown in the video)

 

Download: good-for-improv.syx

 

Original video by Ed Zuccollo: