Hey Joey,
I have still not located any information on the MIDI Read control, and I am not convinced that we can play a MIDI file through it. Today I wanted to set up an example that simply played a MIDI a file through the board, and I was succussful in doing that. I connected a line from my audio out on my PC to the audio in on the SPEEDY, and hooked up some headphones into the audio out on the SPEEDY. I also made sure to switch the audio input jumper from Mic to Line.
I then created a while loop that simply wired AI0 to AO0, and I was able to listen to the file playing on my computer with no problems. Perhaps you can take this approach to analyze the signal.
Regards,
Kevin H
National Instruments
WSN/Wireless DAQ Product Support Engineer