The technology was developed using an ANN CASE tool on the SGI Irix which was later ported to MacOS. It is a proprietary ANN/DSP toolkit that allows generation of ANSI C (and now C++) code from topologies and learning rules that can be user defined and include an arbitrary number of linear and nonlinear elements and DSP processes. Practically everything developed by Prosoniq comes from this tool (which is (c)1990-2006 myself
User interface etc. for the products is a different story, of course. The generated code doesn't provide a user interface (expect for some rudimentary debug log capabilities).
I used Matlab quite a bit in my "early days" but for my day-to-day work I find it unneccessarily complicated as well as counter-intuitive (1-based array indexing and such). Also, while there's an X11 version which kindof runs on MacOS X it is very unstable and just a p.i.t.a. to use, and I don't want to do my development on a PC if there's no good reason for it. Nothing against the PC as such (I do software development for Windows, too), but Macs are just easier for me to work with if I have the choice.