Get the source tarball there: ssr-0.4.2.tar.gz
If you have a Mac, you can also try the SSR Application Bundle: SoundScapeRenderer-0.4.2.dmg
There is also a Debian package available (thanks to IOhannes m zmoelnig): https://packages.debian.org/soundscaperenderer
If you are interested in older releases, check out all downloads.
You should also have a look at the development pages at Github: http://github.com/SoundScapeRenderer/ssr.