I'm in the process of making it possible to move completely to FreeBSD for my primary workstation at home. Currently, I'm using Linux for its ability to run IDJC http://idjc.sourceforge.net for its ability to let me be a shoutcast internet DJ for Radio KoL. This has led me down into the FreeBSD Audio System a bit, which I'm exploring.
I normally run FreeBSD Current, so I came up with a couple of adjustments for my onboard microphones at BSDCan this year after I cornered the hdaa(4) audio maintainer and showed him my confusing. So, for now, I can playback and record with audacity just fine. This does not use the Jack audio system that is required by IDJC.
Jack installed from ports needs a .jackdrc --> "/usr/local/bin/jackd -r -T -d oss -p 2048"
You can test playback with the gstreamer jack plugin in ports along with my favorite audio player, Clementine.