Solved Setting default audio device

I have usb headphones that I want to use with freebsd. The drivers work, and I can get sound the sound working by specifying /dev/dsp7.0. For an example, I can get sound working in mplayer using mplayer -ao oss:/dev/dsp7.0. If I don't do that, there is no sound. So my question is how I can make /dev/dsp7.0 the default audio output.