The connection was:
1) HDSPe MADI Out to Micstasy MADI In
2) Micstasy MADI Out to ADI-642 MADI In
3) ADI-642 MADI Out to HDSPe MADI In
1) is not necessary, but I wanted Logic to be clock master and send remote control commands to the Micstasy. This can easily done with a MADI cable since RME embeds the remote control signals (MIDI commands) into the MADI stream - and extract clock information from the incoming signal. Instead, I could have connected a wordclock cable for the clock and a MIDI cable for the remote control, but my Micstasy is in another room, and of course, one optical line is much simpler ;-)
2) the ADI-642 is a 72*74 Matrix. Input: 64 Ch. MADI, 8 Ch. AES-3 (AES/EBU). Output: 64 Ch. MADI, 8 Ch. AES-3, 2 Ch. Headphone. In this set-up it received a boring MADI signal: Ch. 1 my signal generator plugged into the micstasy microphone input 1, then channel 2-8 some very low noise (from the other 7 AD converters), and no signal on channel 9-64. You wanted me to record 64 channels of audio, so I opened a tool called "RME Midi Remote" (you can download it from the website to test it even if you don't have the devices), selected "ADI-642 Matrix", and with one click I distributed the incoming MADI Channel 1 to all 64 MADI channels on the output. This is why you see 64 same signals recorded in Logic.
3) The Mixer you talk about ("MADI AES-32 Mixer") is in fact the famous Totalmix, a tool that comes with any RME computer interface. This version works for both the MADI cards and the AES-32 cards, that's why it has this long name. Totalmix shows my incoming MADI signal on the first row, then software playback in the middle row (in this case, a 5 channel surround mix that Logic creates) and in the bottom row, it shows the signal that will be on the MADI output of the soundcard. The real power of Totalmix is its ability to mix - independently from Logic, in hardware, with almost no latency - any incoming MADI channel and any Software Playback to any output channel. Take a weekend off and read the Totalmix Manual in combination with the Demo Version from the RME Website. You'll realize that this is a tool you don't want to live without.
Below the mixer you see the remote control of the Micstasy (same RME Midi Remote). This tool gives me access to all functions of the Micstasy, so I don't have to run to the other room to adjust the gain of the Mic preamp... because that is what I do (you see the loudness in- and decreases in the Logic waveform: in fact, these were created by adjusting the gain of the Micstasy). Of course, I also see the state of the Micstasy (SyncCheck, Level Meters and so on - as if the Micstasy was in front of me).
I'm sure it would be easy to write a plugin for Logic to control the gain of the Micstasy within the Logic Mixer, which would be very convenient. But I'm not a programmer, fortunately ;-) Anyway, this doesn't really belong here :-)
Hope this helps,