[rescue] NeXT DSPs

[Big Endian]

Anybody know what the odd simm slot over the DSP in my NeXT cube is? 
If its the DSP ram, I'm SOL because my slot is empty.  How much work 
can I do with it?  I'd like to make it into *perhaps* an MP3/Ogg 
Vorbis player for the house.  Is this possible with the processor 
power in a non turbo cube (utilizing both the 25/50mhz 68040 and the 
50mhz DSP)?  Am I insane for attempting this?  If not who wants to 
help me?

daniel