I'd like to chime in for a couple of things.
First, to congratulate Paul for the great work done in this 3D Sound System. I checked it some days ago and it's really easy to use, powerful and well-documented. I think this was very needed in the Java world, I was using another audio library but it ceased to be maintained around 2006.
And second, to say that if at some point you implement that non-GPL Linux mixer at some point, I (and some other people I know) would be really, really grateful. I maintain a BSD-licensed system that people can use to create text adventures in a relatively easy way. But I have been getting bug reports for years about simultaneous sounds not working under Linux. Over the years, I have checked several audio libraries in search of the holy grail of simultaneous sounds with Java on Linux, but none solves this. In the light of your posts, I suppose this is because none of them implements a software mixer. Having a library that solved this without having to resort to native code or shipping specific versions of the software for each OS (which sets me back a lot) would be a real godsend. And judging by Google searches, not only for me and my users - there are lots of reports of "Java program X doesn't mix sounds under Linux distro Y".
As I said, thanks for the good work and keep it up!