The audio device appears to be controlled by Brio. Attempts to open /dev/dsp fail because it’s already open.
The rest of the audio devices, /dev/audio, /dev/dsp0, /dev/dspW, or /dev/dspW0, are not available.
Short of stumbling upon the libAudioMPI header file, it looks like using sound on the Didj is not possible. It might be possible to build it from the shared library, but it would be very difficult.