bs2b is short for "Bauer stereophonic-to- binaural DSP", an audio effect increasing headphone listening pleasure. Check the well-explained algorithm details for more. I helped with making a shared library from bs2b using the Autotools family: Autoconf, Automake, Libtool, autogen.sh. The just-released libbs2b-2.2.1 is featuring that. bs2b plugins for many popular audio players are already available (e.g. XMMS and Winamp) or in the making and to be released soon (i.e. QMMP). Still, some DSP- supporting players lack a bs2b plugin (e.g. Audacious) and that's a great place for you to step in. Please contact me about details if you're interested.