A little scrutiny revealed that installing blackbox was replacing the the symlinks from libpulsecommon-0.9.21.so -> libpulsecommon-0.9.15.so and from libpulse.so.0.12.2 -> libpulse.so.0.8.0 with libpulsecommon-0.9.21.so -> libpulsecommon-0.9.21.so.real and libpulse.so.0.12.2 -> libpulse.so.0.real. No idea why that would happen...