Csound is a sound and music synthesis system, providing facilities for composition and performance over a wide range of platforms. It is not restricted to any style of music, having been used for many years in at least classical, pop, techno, ambient.
Csound is now hosted at https://github.com/csound
Binary and source-code releases: http://csound.github.io/download.html
Mailing lists are hosted by HEAnet at https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND and https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND-DEV
mail lists at http://dream.cs.bath.ac.uk/Csound-archive
My sound-oriented Android apps have benefitted a lot from Csound5, and I've found the Android implementation to be robust and relatively straightforward to implement and test. The difficulty I often have is finding appropriate examples or documentation of opcodes and .csd syntax. I find it difficult to go from object-oriented Java (abstract, coherent, with lots of good examples) to Csound (concrete, specific, sometimes inconsistent, with not so many examples). I think the community is great (I'm sure I wouldn't have finished these apps without the help of many here)--but it may be time to have another look at the structure of csd with the goal of making it more accessible to a general-purpose developer.